UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Name of Issuer)

(Title of Class of Securities)

(CUSIP Number)

With a copy to:

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because § 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g) check the following box .  ¨

Note: Schedules filed in paper format shall include a signed original and five copies of the schedule, including all exhibits. See § 240.13d-7(b) for other parties to whom copies are to be sent.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

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SCHEDULE 13D

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This statement on Schedule 13D (this “Schedule 13D”) relates to the common stock, par value $.001 per share (the “Shares”), of World Heart Corporation, a Delaware corporation (the “Issuer”). The Issuer’s principal executive offices are located at 4750 Wiley Post Way, Suite 120, Salt Lake City, Utah 84116.

(a) – (c). This Schedule 13D is being filed jointly by HeartWare International, Inc., a Delaware corporation (“HeartWare”) and Ocean Acquisition Holding Inc., a Delaware corporation and an indirect wholly owned subsidiary of HeartWare (“Ocean”). Each of the foregoing is referred to herein as a “Reporting Person” and together as the “Reporting Persons”.

The address of the principal office of each of the Reporting Persons is 205 Newbury Street, Suite 101, Framingham, Massachusetts 01701. The principal business of HeartWare is to develop and manufacture miniaturized implantable heart pumps, or ventricular assist devices, to treat Class IIIB / IV patients suffering from advanced heart failure. Ocean Acquisition Holding Inc. was formed to effect the transactions described in Item 4 below and has not engaged in any activities other than those incident to its formation and such transactions.

The name and principal occupation of the directors and executive officers of the Reporting Persons as of the date hereof are as set forth below. Unless otherwise indicated, each occupation set forth opposite an individual’s name refers to a position with the applicable Reporting Person. The business address of each of the below individuals is 205 Newbury Street, Suite 101, Framingham, Massachusetts 01701.

1. HeartWare International, Inc.

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2. Ocean Acquisition Holding Inc.

(d) – (e). During the past five years, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any of the directors and executive officers identified above has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).

During the last five years, none of the Reporting Persons or, to the best knowledge of the Reporting Persons, any of the directors and executive officers identified above has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

(f). The Reporting Persons are Delaware corporations. All of the directors and executive officers of HeartWare and Ocean set forth above are United States citizens, except for Robert Thomas, Christine Bennett and Denis Wade, who are citizens of Australia.

As an inducement to HeartWare and Ocean to enter into the Merger Agreement (as defined and described in Item 4 below), HeartWare and Ocean entered into Voting Agreements, dated as of March 29, 2012, described in Item 4 of this Schedule 13D (the terms of which are hereby incorporated by reference) with each of the following stockholders of Issuer: (i) New Leaf Ventures II, L.P. (“New Leaf”); (ii) Austin W. Marxe (“Marxe”); and (iii) Venrock Associates V, L.P. (“Venrock Associates”), Venrock Partners V, L.P. (“Venrock Partners”) and Venrock Entrepreneurs Fund V, L.P. (“Venrock Entrepreneurs”) (each agreement, a “Voting Agreement”, and together, the “Voting Agreements”). HeartWare and Ocean did not pay, or agree to pay, additional consideration in connection with the execution and delivery of the Voting Agreements.

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(a) – (b). On March 29, 2012, HeartWare, Ocean and the Issuer entered into an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”) providing for the merger (the “Merger”) of Ocean with and into the Issuer, which will result in the Issuer becoming an indirect wholly owned subsidiary of HeartWare. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger, each of the Shares issued and outstanding immediately prior to the effective time will either be converted into the right to receive the number of shares of HeartWare common stock equal to the quotient determined by dividing the per share merger consideration by the average of the per share closing prices of HeartWare common stock on NASDAQ during the ten consecutive trading days ending on (and including) the trading day that is one calendar day prior to the date of the closing of the transaction or cash equal to the per share merger consideration, at HeartWare’s election. The per share merger consideration will be determined by dividing $8 million by the number of Shares outstanding on a fully diluted basis (including out of the money options and warrants and warrants subject to a put right). The closing of the Merger is subject to the approval of World Heart’s stockholders and the satisfaction of other customary closing conditions.

In connection with the Merger Agreement, New Leaf entered into a Voting Agreement with HeartWare and Ocean with respect to 4,488,264 Shares owned by New Leaf, Marxe entered into a Voting Agreement with HeartWare and Ocean with respect to 1,015,286 Shares owned by Marxe, and Venrock Associates, Venrock Partners and Venrock Entrepreneurs entered into a Voting Agreement with HeartWare and Ocean with respect to 5,560,644 Shares, 130,650 Shares and 471,450 Shares owned by Venrock Associates, Venrock Partners and Venrock Entrepreneurs, respectively. Subject to the terms and conditions of the Voting Agreements, each of New Leaf, Marxe, Venrock Associates, Venrock Partners and Venrock Entrepreneurs has agreed to vote (or cause to be voted) the aforementioned number of Shares beneficially owned by New Leaf, Marxe, Venrock Associates, Venrock Partners and Venrock Entrepreneurs, resulting in an aggregate amount of 11,666,294 Shares (the “Covered Shares”), (a) in favor of the Merger, the adoption of the Merger Agreement and approval of the terms thereof and each of the other transactions contemplated by the Voting Agreements and the Merger Agreement and (b) against any action, proposal, transaction or agreement which would reasonably be expected to impede, interfere with, delay, discourage, adversely affect or inhibit the timely consummation of the Merger or the fulfillment of HeartWare’s, the Issuer’s or Ocean’s conditions under the Merger Agreement or change in any manner the voting rights of any security of the Issuer (including by any amendments to the Issuer’s charter or bylaws). New Leaf, Marxe, Venrock Associates, Venrock Partners and Venrock Entrepreneurs irrevocably granted to and appointed HeartWare and any designee of HeartWare, alone or together, proxy, attorney-in-fact and agent to vote the Covered Shares as described above. New Leaf, Marxe, Venrock Associates, Venrock Partners and Venrock Entrepreneurs each also agreed to refrain from selling, transferring (including by operation of law), pledging, assigning or otherwise encumbering or disposing of, or entering into any agreement, option or other arrangement (including any profit sharing arrangement) or understanding with respect to any of the Shares to any person other than HeartWare or HeartWare’s designee. The Voting Agreements terminate upon the first to occur of the consummation of the Merger, the termination of the Merger Agreement in accordance with its terms or the mutual written agreement of the parties to each Voting Agreement to terminate the Voting Agreement.

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(c). Not applicable.

(d). If the Merger is completed as planned, the board of directors of the Issuer will consist of the directors of Ocean immediately prior to the consummation of the Merger and the officers of the Issuer will consist of the officers of Ocean immediately prior to the consummation of the Merger, in each case until their respective successors are duly elected and qualified or until the earlier of their death, resignation or removal.

(e). The Issuer has never paid cash dividends on the Shares. Under the terms of the Merger Agreement, the Issuer may not, without HeartWare’s prior written consent, among other things, declare, set aside, make or pay any dividend or other distribution, payable in cash, stock, property or otherwise, with respect to any of its capital stock, except for dividends by any of the Issuer’s direct or indirect wholly owned subsidiaries to the Issuer or any of its other wholly owned subsidiaries.

(f). Upon the consummation of the Merger, the Issuer, as the surviving corporation in the Merger, will become an indirect, wholly owned subsidiary of HeartWare.

(g). At the time of the consummation of the Merger, the certificate of incorporation of the Issuer shall be amended in its entirety to read the same as the certificate of incorporation of Ocean as in effect immediately prior to the consummation of the Merger; provided, however, that Article I thereof shall be amended to read as follows: “The name of the corporation is World Heart Corporation.” Unless otherwise determined by HeartWare prior to the consummation of the Merger, at the time of consummation of the Merger, the bylaws of the Issuer shall be amended and restated in their entirety to read the same as the bylaws of Ocean as in effect immediately prior to the consummation of the Merger.

(h). Upon consummation, the Merger will result in the Shares no longer being listed on NASDAQ.

(i). Upon the consummation of the Merger, the Shares will become eligible for termination of registration pursuant to Section 12(g)(4) of the Securities Exchange Act of 1934, as amended.

(j). Other than as described above, none of the Reporting Persons has any plans or proposals that relate to or would result in any of the actions described in subparagraphs (a) through (i) of Item 4 of Schedule 13D (although the Reporting Persons reserve the right to develop such plans).

The preceding summary of certain provisions of the Merger Agreement and the Voting Agreements is not intended to be complete and is qualified in its entirety by reference to the full text of such agreements, copies of which are filed as Exhibits 1, 2, 3 and 4 hereto, and which are incorporated herein by reference.

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(a) – (b). As of the date hereof, HeartWare and Ocean own no Shares. HeartWare and Ocean may, however, be deemed to have shared voting power with respect to 11,666,294 Shares, which are subject to the Voting Agreements described above in Item 4 and which represent 42.4% of the outstanding Shares. The percentages used herein are calculated based upon 27,517,749 Shares outstanding at March 30, 2012, as disclosed in the Issuer’s Annual Report filed on Form 10-K on March 30, 2012.

The number of outstanding Shares that may be deemed to be beneficially owned by HeartWare and Ocean with respect to which there is (i) sole voting power is none, (ii) shared voting power is 11,666,294 Shares, with respect to those matters described in Item 4 of this Schedule 13D, (iii) sole dispositive power is none, and (iv) shared dispositive power is none.

The filing of this Schedule 13D by the Reporting Persons shall not be considered an admission that the Reporting Persons, for any or all purposes, are the beneficial owners of any of the Shares covered by this Schedule 13D.

(c). Except as set forth in this Schedule 13D with reference to the Merger Agreement and the Voting Agreements, neither the Reporting Persons nor, to the knowledge of the Reporting Persons, any director or officer of the Reporting Persons listed in Item 2(a) – (c), has effected any transaction in the Shares during the past 60 days.

(d). To the knowledge of the Reporting Persons, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Covered Shares.

(e). Not applicable.

Other than as described in Items 3, 4 and 5, which are incorporated herein by reference, and in the agreements and documents attached as exhibits hereto or incorporated herein by reference, to the knowledge of the Reporting Persons, there are no contracts, arrangements, understandings or relationships (legal or otherwise) among the persons named in Item 2 or between such persons and any other person with respect to any securities of the Issuer, including but not limited to transfer or voting of any of the securities, finder’s fees, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving or withholding of proxies, the existence of which would give another person voting or investment power over the securities of the Issuer.

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SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: April 5, 2012

Exhibit Index

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Exhibit 1.2

FINAL VERSION

VOTING AGREEMENT

This Voting Agreement (this “Agreement”) is entered into as of March 29, 2012 among HeartWare International, Inc., a Delaware corporation (“Parent”), Ocean Acquisition Holding Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (“Merger Sub”), and the person listed as a stockholder of World Heart Corporation, a Delaware corporation (the “Company”) on the signature page hereto (the “Stockholder”).

RECITALS

A. Concurrently with the execution and delivery of this Agreement, the Company, Merger Sub and Parent are entering into an Agreement and Plan of Merger (as the same may be amended or supplemented, the “Merger Agreement”), which provides, among other things, for the acquisition of the Company by Parent by means of a merger of Merger Sub with and into the Company (the “Merger”), all on the terms and subject to the conditions set forth in the Merger Agreement. Capitalized terms used herein that are not defined shall have the meanings set forth in the Merger Agreement.

B. The Stockholder is the record and beneficial owner of the number of shares of Company Common Stock set forth on Part I of Exhibit A hereto (such securities, as they may be adjusted by stock dividend, stock split, recapitalization, combination or exchange of shares, merger, consolidation, reorganization or other change or transaction of or by the Company, together with securities of the Company that may be acquired after the date hereof by the Stockholder are collectively referred to herein as the “Securities”).

C. As an inducement and a condition to the willingness of Parent and Merger Sub to enter into the Merger Agreement, and in consideration of the substantial expenses incurred and to be incurred by them in connection therewith, the Stockholder has agreed to enter into, be legally bound by and perform this Agreement.

AGREEMENTS

In consideration of the recitals and the representations, warranties, covenants and agreements contained herein, and intending to be legally bound hereby, the parties hereto agree as follows:

1. Covenants of the Stockholder. The Stockholder agrees as follows:

(a) The Stockholder shall not, directly or indirectly, (i) sell, transfer (including by operation of law), pledge, assign or otherwise encumber or dispose of, or enter into any agreement, option or other arrangement (including any profit sharing arrangement) or understanding with respect to any of the Securities to any person other than Parent or Parent’s designee, (ii) deposit any Securities into a voting trust or enter into any voting arrangement, whether by proxy, voting agreement, voting trust, power-of-attorney, attorney-in-fact, agent or otherwise, with respect to the Securities, except as contemplated by this Agreement, or (iii) take any other action that would in any way make any representation or warranty of the Stockholder herein untrue or incorrect in any material respect or otherwise restrict, limit or interfere in any material respect with the performance of the Stockholder’s obligations hereunder or the transactions contemplated hereby.

(b) At any meeting of stockholders of the Company called to vote upon the Merger and the Merger Agreement or at any adjournment thereof or in any other circumstances upon which a vote, consent or other approval (including by written consent) is sought with respect to the Merger and the Merger Agreement, the Stockholder shall vote (or cause to be voted) the number of its Securities set forth in Part II of Exhibit A hereto in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement.

(c) The Stockholder shall take, or cause to be taken, all reasonable actions, and to do, or cause to be done, and to assist and cooperate with the Company and Parent in doing, all things reasonably necessary to consummate and make effective, in the most expeditious manner practicable, the Merger and the other transactions contemplated by the Merger Agreement, including, without limitation, (i) causing the Company to call the Company Stockholders’ Meeting for the purpose of considering, acting upon and voting upon the approval and adoption of the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement (or executing valid and effective written consents in lieu of a meeting of the holders of the minimum number of shares of Company Common Stock required to approve the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement), (ii) attending, if applicable, the Company Stockholders’ Meeting or any adjournment thereof (or executing valid and effective proxies to any other attending participant of a Company Stockholders’ Meeting in lieu of attending such Company Stockholders’ Meeting or any adjournment thereof), and (iii) causing the Company to postpone or adjourn, at Parent’s request, the Company Stockholders’ Meeting on one occasion for up to fifteen (15) Business Days (but in any event no later than the Outside Date) (x) in order to solicit additional proxies for the purpose of obtaining the Company Stockholder Approval (unless prior to such adjournment the Company shall have received an aggregate number of proxies voting for the adoption of the Merger Agreement, which have not been withdrawn, such that the condition in Section 8.01(b) of the Merger Agreement will be satisfied at such meeting), (y) if a quorum is not present or (z) in order to allow reasonable additional time for (A) the filing and mailing of, at the reasonable request of Parent, any supplemental or amended disclosure and (B) such supplemental or amended disclosure to be disseminated to, and reviewed by, the stockholders of the Company prior to the Company Stockholders’ Meeting.

(d) The Stockholder shall not, directly or indirectly, through any officer, director, agent or other representative, (i) solicit, initiate or encourage (including by way of furnishing nonpublic information), or take any other action to facilitate, any inquiries or the making of any proposal or offer (including any proposal or offer to the Company’s stockholders) with respect to any Competing Transaction (a “Competing Proposal”) or (ii) enter into, maintain, continue or otherwise engage or participate in any discussions or negotiations with any Person or entity in furtherance of such inquiries or to obtain a proposal or offer with respect to a Competing Transaction. The Stockholder shall, and shall direct or cause its representatives and agents to, immediately cease and cause to be terminated any discussions or negotiations with any parties that may be ongoing with respect to (or that could be reasonably expected to lead to) a Competing Proposal. The Stockholder shall promptly notify Parent, orally and in writing, after the receipt by the Stockholder of any proposal, inquiry, offer or request (or any amendment thereto) with respect to a Competing Transaction including any request for discussions or negotiations. Such notice shall indicate the identity of the Person making such proposal, inquiry, offer or request and a description of such proposal, inquiry, offer or request, including the terms and conditions (if any) of such proposed Competing Transaction.

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(e) The Stockholder shall vote (or cause to be voted) its Securities against (i) any Competing Proposal and (ii) any action, proposal, transaction or agreement which would reasonably be expected to impede, interfere with, delay, discourage, adversely affect or inhibit the timely consummation of the Merger or the fulfillment of Parent’s, the Company’s or Merger Sub’s conditions under the Merger Agreement or change in any manner the voting rights of any security of the Company (including by any amendments to the Company’s charter or bylaws).

2. Grant of Irrevocable Proxy Coupled with an Interest; Appointment of Proxy.

(a) The Stockholder hereby irrevocably (i) grants to Parent and any designee of Parent, alone or together, the Stockholder’s proxy, and (ii) appoints Parent and any designee of Parent as the Stockholder’s proxy, attorney-in-fact and agent (with full power of substitution and resubstitution), alone or together, for and in the name, place and stead of the Stockholder, to vote the Securities, or grant a consent or approval in respect of the Securities, in accordance with Section 1 above at any meeting of the stockholders of the Company or at any adjournment thereof or in any other circumstances upon which their vote, consent or other approval is sought in favor of the Merger, the adoption by the Company of the Merger Agreement and the approval of the other transactions contemplated by the Merger Agreement. The Stockholder agrees to execute such documents or certificates evidencing such proxy as Parent may reasonably request. The Stockholder acknowledges receipt and review of a copy of the Merger Agreement.

(b) The Stockholder represents that any proxies heretofore given in respect of the Securities are not irrevocable, and that any such proxies are hereby revoked.

(c) THE STOCKHOLDER HEREBY AFFIRMS THAT THE PROXY SET FORTH IN THIS SECTION 2 IS COUPLED WITH AN INTEREST AND IS IRREVOCABLE UNTIL SUCH TIME AS THIS AGREEMENT TERMINATES IN ACCORDANCE WITH ITS TERMS. The Stockholder hereby further affirms that the irrevocable proxy is given in connection with the execution of the Merger Agreement, and that such irrevocable proxy is given to secure the performance of the duties of the Stockholder under this Agreement. The Stockholder hereby ratifies and confirms all that such irrevocable proxy may lawfully do or cause to be done by virtue hereof. Such irrevocable proxy shall be valid until the termination of this Agreement in accordance with its terms. The power of attorney granted by the Stockholder is a durable power of attorney and shall survive the bankruptcy, dissolution, death or incapacity of the Stockholder.

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3. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to Parent and Merger Sub as follows:

(a) The Stockholder has all requisite power and authority to execute and deliver this Agreement and to perform the Stockholder’s obligations under this Agreement. The execution, delivery and performance of this Agreement have been duly authorized by the Stockholder. This Agreement has been duly executed and delivered by the Stockholder and, assuming this Agreement constitutes a valid and binding obligation of Parent and Merger Sub, constitutes a valid and binding obligation of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies.

(b) The Securities and the certificates (or any book-entry notations used to represented any uncertificated shares of Company Common Stock) representing the Securities are now, and at all times during the term hereof will be, held by the Stockholder, or by a nominee or custodian for the benefit of the Stockholder, and the Stockholder has title to the Securities, free and clear of any Encumbrances (including voting trusts and voting commitments), except as provided by this Agreement. As of the date of this Agreement, the Stockholder owns of record or beneficially no securities of the Company, or any options, warrants or rights exercisable for securities of the Company, other than the Securities set forth on Part I of Exhibit A hereto. The Stockholder has full power to vote the Securities as provided herein. Neither the Stockholder nor any of the Securities is subject to any voting trust, proxy or other agreement, arrangement or restriction with respect to the voting or disposition of the Securities, except as otherwise contemplated by this Agreement or the Merger Agreement.

(c)(i) No filing with, and no permit, authorization, consent or approval of any state, federal or foreign governmental authority is necessary on the part of the Stockholder for the execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the Stockholder’s obligations under this Agreement and (ii) neither the execution and delivery of this Agreement by the Stockholder nor the performance by the Stockholder of the Stockholder’s obligations under this Agreement nor compliance by the Stockholder with any of the provisions hereof shall (x) result in the creation of an encumbrance on any of the Securities or (y) violate any order, writ, injunction, decree, statute, rule or regulation applicable to the Stockholder or any of the Securities, except in the case of (x) or (y) for violations, breaches or defaults that would not in the aggregate materially impair the ability of the Stockholder to perform its obligations hereunder.

(d) The Stockholder understands and acknowledges that Parent and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution and delivery of this Agreement.

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(e) The Stockholder represents and warrants to Parent and Merger Sub that none of the information relating to the Stockholder and its affiliates provided by or on behalf of the Stockholder or its affiliates for inclusion in the Proxy Statement will, at the respective times that the Proxy Statement is filed with the SEC or is first mailed to the holders of the Company Common Stock, contain any untrue statement of material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The Stockholder authorizes and agrees to permit Parent and Merger Sub to publish and disclose in the Proxy Statement and any related filings under the securities laws of the United States or any state thereof the Stockholder’s identity and ownership of Securities and the nature of its commitments, arrangements and understandings under this Agreement and any other information required by applicable Law.

4. Representations and Warranties of Parent and Merger Sub. Parent and Merger Sub hereby jointly and severally represent and warrant to the Stockholder as follows: Parent and Merger Sub have the requisite corporate power and authority to execute and deliver this Agreement and to consummate the transactions contemplated hereby; the execution, delivery and performance of this Agreement by Parent and Merger Sub and the consummation of the transactions contemplated hereby have been duly authorized by all necessary corporate action on the part of Parent and Merger Sub; and this Agreement has been duly executed and delivered by Parent and Merger Sub and, assuming this Agreement constitutes a valid and binding obligation of the Stockholder, constitutes a valid and binding obligation of Parent and Merger Sub enforceable against each of them in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies.

5. Further Assurances. The Stockholder will, from time to time, execute and deliver, or cause to be executed and delivered, in each case without further consideration, such additional or further transfers, assignments, endorsements, consents and other instruments as Parent may reasonably request for the purpose of effectively carrying out the Stockholder’s obligations under this Agreement and to vest the power to vote the Securities as contemplated by Section 2. Parent agrees to take, or cause to be taken, (i) all actions reasonably necessary to comply promptly with all legal requirements that may be imposed with respect to the transactions contemplated by this Agreement and (ii) all actions reasonably necessary or desirable to consummate the transactions contemplated by this Agreement.

6. Assignment; Binding Effect. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any of the parties hereto (whether by operation of law or otherwise) without the prior written consent of the other parties, except that Parent may assign all or any of its rights and obligations hereunder to any affiliate of Parent; provided, however, that no such assignment shall relieve the assigning party of its obligations hereunder if such assignee does not perform such obligations. Subject to the preceding sentence, this Agreement shall be binding upon, inure solely to the benefit of, and be enforceable by, the parties hereto and their respective permitted successors and assigns. Notwithstanding anything contained in this Agreement to the contrary, nothing in this Agreement, expressed or implied, is intended to or shall confer on any person other than the parties hereto or their respective heirs, successors, executors, administrators and assigns any rights, benefits, remedies, obligations or liabilities of any nature whatsoever under or by reason of this Agreement.

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7. Termination. This Agreement, and all rights and obligations of the parties hereunder, shall terminate upon the first to occur of (i) the Effective Time, (ii) the date on which the Merger Agreement is terminated in accordance with its terms or (iii) the mutual written agreement of the parties to terminate this Agreement. In the event of termination of this Agreement pursuant to this Section 7, this Agreement will become null and void and of no effect with no liability on the part of any party hereto; provided, however, that no such termination will relieve any party hereto from any liability for any willful breach of this Agreement occurring prior to such termination.

8. Stockholder Capacity. Notwithstanding anything to the contrary in this Agreement, the parties acknowledge that (a) the Stockholder is entering into this Agreement solely in the Stockholder’s capacity as a record and/or beneficial owner of the Company Common Stock and not in such Stockholder’s capacity as a director, officer or employee of the Company (if applicable) or in such Stockholder’s capacity as a trustee or fiduciary of any Plans and (b) nothing in this Agreement is intended to restrict or affect any action or inaction of the Stockholder or any representative of the Stockholder, as applicable, serving on the Company Board or on the board of directors of any Subsidiary of the Company or as an officer or fiduciary of the Company or any Subsidiary of the Company, acting in such Person’s capacity as a director, officer, employee or fiduciary of the Company or any Subsidiary of the Company.

9. General Provisions.

(a) Except as otherwise set forth in the Merger Agreement, all costs and expenses incurred in connection with this Agreement and the transactions contemplated hereby shall be paid by the party incurring such expense, whether or not the transactions contemplated hereby are consummated.

(b) Any provision of this Agreement may be amended or waived if, and only if, such amendment or waiver is in a writing that refers to this Agreement and signed, in the case of an amendment, by each of the parties hereto, or in the case of a waiver, by the party against whom the waiver is to be effective. No failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies provided by applicable law.

(c) Any notice, demand, or communication required or permitted to be given by any provision of this Agreement shall be deemed to have been sufficiently given or served for all purposes if (i) personally delivered, (ii) mailed by registered or certified first-class mail, prepaid with return receipt requested, (iii) sent by a nationally recognized overnight courier service, to the recipient at the address below indicated or (iv) delivered by facsimile or email which is confirmed in writing by sending a copy of such facsimile or email to the recipient thereof pursuant to clause (i) or (iii) above:

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If to Parent or Merger Sub:

HeartWare International, Inc.

205 Newbury Street, Suite 101

Framingham, MA 01701

With a required copy to (which shall not constitute notice):

Shearman & Sterling LLP

599 Lexington Avenue

New York, NY 10022

If to the Stockholder:

At the address and facsimile number and email address set forth set forth in Part I of Exhibit A hereto;

or to such other address as any party hereto may, from time to time, designate in a written notice given in like manner.

(d) When a reference is made in this Agreement to a Section, such reference shall be to a Section of this Agreement unless otherwise indicated. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Wherever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

(e) This Agreement may be executed in one or more counterparts, all of which shall be considered one and the same agreement and shall become effective when two or more counterparts have been signed by each of the parties and delivered to the other parties, it being understood that all parties need not sign the same counterpart. Signatures delivered by facsimile or electronic transmission shall be binding for all purposes hereof.

(f) This Agreement and the Merger Agreement constitute the entire agreement and supersede all prior agreements and understandings, both written and oral, among the parties, or any of them, with respect to the subject matter hereof.

(g) This Agreement shall be governed and construed in accordance with the laws of the State of Delaware without regard to any applicable conflicts of law.

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(h) Each party hereto hereby irrevocably and unconditionally submits, for itself and its property, to the exclusive jurisdiction and proper venue of the Court of Chancery of the State of Delaware, and each party consents to personal and subject matter jurisdiction and venue in such courts and waives and relinquishes all right to attack the suitability or convenience of such venue or forum by reason of their present or future domiciles, or by any other reason. The parties acknowledge that all directions issued by the forum court, including all injunctions and other decrees, will be binding and enforceable in all jurisdictions and countries. Each of the parties hereto hereby waives to the fullest extent permitted by applicable Law any right it may have to a trial by jury with respect to any litigation directly or indirectly arising out of, under or in connection with this Agreement or the transactions contemplated hereby.

(i) If any provision of this Agreement or the application thereof to any party or set of circumstances shall, in any jurisdiction and to any extent, be finally held invalid or unenforceable by any rule of law or public policy, such term or provision shall only be ineffective as to such jurisdiction, and only to the extent of such invalidity or unenforceability, without invalidating or rendering unenforceable any other terms or provisions of this Agreement or under any other circumstances, and the parties shall negotiate in good faith a substitute provision which comes as close as possible to the invalidated or unenforceable term or provision, and which puts each party in a position as nearly comparable as possible to the position it would have been in but for the finding of invalidity or unenforceability, while remaining valid and enforceable.

(j) Each of the parties acknowledges that irreparable damage would occur in the event any provision of this Agreement was not performed in accordance with the terms hereof and agrees that the parties’ respective remedies at law for a breach or threatened breach of any of the provisions of this Agreement would be inadequate and, in recognition of that fact, each agrees that, in the event of a breach or threatened breach by any party of the provisions of this Agreement, in addition to any remedies at law, each party, respectively, without posting any bond, shall be entitled to seek equitable relief in the form of specific performance, a temporary restraining order, a temporary or permanent injunction or any other equitable remedy which may then be available.

[Signature pages follow]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

[Voting Agreement]

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Exhibit A

Stockholder Security Ownership and Voting Information

Part I

Part II

Number and Class of Securities held by Stockholder to be voted, pursuant to Section 1(b), in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement, or necessary to the consummation of such transactions, as to which the Company stockholders are called upon to vote, consent or approve:

Exhibit 1.3

FINAL VERSION

VOTING AGREEMENT

This Voting Agreement (this “Agreement”) is entered into as of March 29, 2012 among HeartWare International, Inc., a Delaware corporation (“Parent”), Ocean Acquisition Holding Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (“Merger Sub”), and the person listed as a stockholder of World Heart Corporation, a Delaware corporation (the “Company”) on the signature page hereto (the “Stockholder”).

RECITALS

A. Concurrently with the execution and delivery of this Agreement, the Company, Merger Sub and Parent are entering into an Agreement and Plan of Merger (as the same may be amended or supplemented, the “Merger Agreement”), which provides, among other things, for the acquisition of the Company by Parent by means of a merger of Merger Sub with and into the Company (the “Merger”), all on the terms and subject to the conditions set forth in the Merger Agreement. Capitalized terms used herein that are not defined shall have the meanings set forth in the Merger Agreement.

B. The Stockholder is the record and beneficial owner of the number of shares of Company Common Stock set forth on Part I of Exhibit A hereto (such securities, as they may be adjusted by stock dividend, stock split, recapitalization, combination or exchange of shares, merger, consolidation, reorganization or other change or transaction of or by the Company, together with securities of the Company that may be acquired after the date hereof by the Stockholder are collectively referred to herein as the “Securities”).

C. As an inducement and a condition to the willingness of Parent and Merger Sub to enter into the Merger Agreement, and in consideration of the substantial expenses incurred and to be incurred by them in connection therewith, the Stockholder has agreed to enter into, be legally bound by and perform this Agreement.

AGREEMENTS

In consideration of the recitals and the representations, warranties, covenants and agreements contained herein, and intending to be legally bound hereby, the parties hereto agree as follows:

1. Covenants of the Stockholder. The Stockholder agrees as follows:

(a) The Stockholder shall not, directly or indirectly, (i) sell, transfer (including by operation of law), pledge, assign or otherwise encumber or dispose of, or enter into any agreement, option or other arrangement (including any profit sharing arrangement) or understanding with respect to any of the Securities to any person other than Parent or Parent’s designee, (ii) deposit any Securities into a voting trust or enter into any voting arrangement, whether by proxy, voting agreement, voting trust, power-of-attorney, attorney-in-fact, agent or otherwise, with respect to the Securities, except as contemplated by this Agreement, or (iii) take any other action that would in any way make any representation or warranty of the Stockholder herein untrue or incorrect in any material respect or otherwise restrict, limit or interfere in any material respect with the performance of the Stockholder’s obligations hereunder or the transactions contemplated hereby.

(b) At any meeting of stockholders of the Company called to vote upon the Merger and the Merger Agreement or at any adjournment thereof or in any other circumstances upon which a vote, consent or other approval (including by written consent) is sought with respect to the Merger and the Merger Agreement, the Stockholder shall vote (or cause to be voted) the number of its Securities set forth in Part II of Exhibit A hereto in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement.

(c) The Stockholder shall take, or cause to be taken, all reasonable actions, and to do, or cause to be done, and to assist and cooperate with the Company and Parent in doing, all things reasonably necessary to consummate and make effective, in the most expeditious manner practicable, the Merger and the other transactions contemplated by the Merger Agreement, including, without limitation, (i) causing the Company to call the Company Stockholders’ Meeting for the purpose of considering, acting upon and voting upon the approval and adoption of the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement (or executing valid and effective written consents in lieu of a meeting of the holders of the minimum number of shares of Company Common Stock required to approve the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement), (ii) attending, if applicable, the Company Stockholders’ Meeting or any adjournment thereof (or executing valid and effective proxies to any other attending participant of a Company Stockholders’ Meeting in lieu of attending such Company Stockholders’ Meeting or any adjournment thereof), and (iii) causing the Company to postpone or adjourn, at Parent’s request, the Company Stockholders’ Meeting on one occasion for up to fifteen (15) Business Days (but in any event no later than the Outside Date) (x) in order to solicit additional proxies for the purpose of obtaining the Company Stockholder Approval (unless prior to such adjournment the Company shall have received an aggregate number of proxies voting for the adoption of the Merger Agreement, which have not been withdrawn, such that the condition in Section 8.01(b) of the Merger Agreement will be satisfied at such meeting), (y) if a quorum is not present or (z) in order to allow reasonable additional time for (A) the filing and mailing of, at the reasonable request of Parent, any supplemental or amended disclosure and (B) such supplemental or amended disclosure to be disseminated to, and reviewed by, the stockholders of the Company prior to the Company Stockholders’ Meeting.

(d) The Stockholder shall not, directly or indirectly, through any officer, director, agent or other representative, (i) solicit, initiate or encourage (including by way of furnishing nonpublic information), or take any other action to facilitate, any inquiries or the making of any proposal or offer (including any proposal or offer to the Company’s stockholders) with respect to any Competing Transaction (a “Competing Proposal”) or (ii) enter into, maintain, continue or otherwise engage or participate in any discussions or negotiations with any Person or entity in furtherance of such inquiries or to obtain a proposal or offer with respect to a Competing Transaction. The Stockholder shall, and shall direct or cause its representatives and agents to, immediately cease and cause to be terminated any discussions or negotiations with any parties that may be ongoing with respect to (or that could be reasonably expected to lead to) a Competing Proposal. The Stockholder shall promptly notify Parent, orally and in writing, after the receipt by the Stockholder of any proposal, inquiry, offer or request (or any amendment thereto) with respect to a Competing Transaction including any request for discussions or negotiations. Such notice shall indicate the identity of the Person making such proposal, inquiry, offer or request and a description of such proposal, inquiry, offer or request, including the terms and conditions (if any) of such proposed Competing Transaction.

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(e) The Stockholder shall vote (or cause to be voted) its Securities against (i) any Competing Proposal and (ii) any action, proposal, transaction or agreement which would reasonably be expected to impede, interfere with, delay, discourage, adversely affect or inhibit the timely consummation of the Merger or the fulfillment of Parent’s, the Company’s or Merger Sub’s conditions under the Merger Agreement or change in any manner the voting rights of any security of the Company (including by any amendments to the Company’s charter or bylaws).

2. Grant of Irrevocable Proxy Coupled with an Interest; Appointment of Proxy.

(a) The Stockholder hereby irrevocably (i) grants to Parent and any designee of Parent, alone or together, the Stockholder’s proxy, and (ii) appoints Parent and any designee of Parent as the Stockholder’s proxy, attorney-in-fact and agent (with full power of substitution and resubstitution), alone or together, for and in the name, place and stead of the Stockholder, to vote the Securities, or grant a consent or approval in respect of the Securities, in accordance with Section 1 above at any meeting of the stockholders of the Company or at any adjournment thereof or in any other circumstances upon which their vote, consent or other approval is sought in favor of the Merger, the adoption by the Company of the Merger Agreement and the approval of the other transactions contemplated by the Merger Agreement. The Stockholder agrees to execute such documents or certificates evidencing such proxy as Parent may reasonably request. The Stockholder acknowledges receipt and review of a copy of the Merger Agreement.

(b) The Stockholder represents that any proxies heretofore given in respect of the Securities are not irrevocable, and that any such proxies are hereby revoked.

(c) THE STOCKHOLDER HEREBY AFFIRMS THAT THE PROXY SET FORTH IN THIS SECTION 2 IS COUPLED WITH AN INTEREST AND IS IRREVOCABLE UNTIL SUCH TIME AS THIS AGREEMENT TERMINATES IN ACCORDANCE WITH ITS TERMS. The Stockholder hereby further affirms that the irrevocable proxy is given in connection with the execution of the Merger Agreement, and that such irrevocable proxy is given to secure the performance of the duties of the Stockholder under this Agreement. The Stockholder hereby ratifies and confirms all that such irrevocable proxy may lawfully do or cause to be done by virtue hereof. Such irrevocable proxy shall be valid until the termination of this Agreement in accordance with its terms. The power of attorney granted by the Stockholder is a durable power of attorney and shall survive the bankruptcy, dissolution, death or incapacity of the Stockholder.

3. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to Parent and Merger Sub as follows:

(a) The Stockholder has all requisite power and authority to execute and deliver this Agreement and to perform the Stockholder’s obligations under this Agreement. The execution, delivery and performance of this Agreement have been duly authorized by the Stockholder. This Agreement has been duly executed and delivered by the Stockholder and, assuming this Agreement constitutes a valid and binding obligation of Parent and Merger Sub, constitutes a valid and binding obligation of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies. The failure of the spouse, if any, of the Stockholder to be a party or signatory to this Agreement shall not (x) prevent the Stockholder from performing the Stockholder’s obligations contemplated hereunder or (y) prevent this Agreement from constituting the legal, valid and binding obligation of the Stockholder in accordance with its terms.

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(b) The Securities and the certificates (or any book-entry notations used to represented any uncertificated shares of Company Common Stock) representing the Securities are now, and at all times during the term hereof will be, held by the Stockholder, or by a nominee or custodian for the benefit of the Stockholder, and the Stockholder has title to the Securities, free and clear of any Encumbrances (including voting trusts and voting commitments), except as provided by this Agreement. As of the date of this Agreement, the Stockholder owns of record or beneficially no securities of the Company, or any options, warrants or rights exercisable for securities of the Company, other than the Securities set forth on Part I of Exhibit A hereto. The Stockholder has full power to vote the Securities as provided herein. Neither the Stockholder nor any of the Securities is subject to any voting trust, proxy or other agreement, arrangement or restriction with respect to the voting or disposition of the Securities, except as otherwise contemplated by this Agreement or the Merger Agreement.

(c)(i) No filing with, and no permit, authorization, consent or approval of any state, federal or foreign governmental authority is necessary on the part of the Stockholder for the execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the Stockholder’s obligations under this Agreement and (ii) neither the execution and delivery of this Agreement by the Stockholder nor the performance by the Stockholder of the Stockholder’s obligations under this Agreement nor compliance by the Stockholder with any of the provisions hereof shall (x) result in the creation of an encumbrance on any of the Securities or (y) violate any order, writ, injunction, decree, statute, rule or regulation applicable to the Stockholder or any of the Securities, except in the case of (x) or (y) for violations, breaches or defaults that would not in the aggregate materially impair the ability of the Stockholder to perform its obligations hereunder.

(d) The Stockholder understands and acknowledges that Parent and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution and delivery of this Agreement.

(e) The Stockholder represents and warrants to Parent and Merger Sub that none of the information relating to the Stockholder and its affiliates provided by or on behalf of the Stockholder or its affiliates for inclusion in the Proxy Statement will, at the respective times that the Proxy Statement is filed with the SEC or is first mailed to the holders of the Company Common Stock, contain any untrue statement of material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The Stockholder authorizes and agrees to permit Parent and Merger Sub to publish and disclose in the Proxy Statement and any related filings under the securities laws of the United States or any state thereof the Stockholder’s identity and ownership of Securities and the nature of its commitments, arrangements and understandings under this Agreement and any other information required by applicable Law.

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4. Representations and Warranties of Parent and Merger Sub. Parent and Merger Sub hereby jointly and severally represent and warrant to the Stockholder as follows: Parent and Merger Sub have the requisite corporate power and authority to execute and deliver this Agreement and to consummate the transactions contemplated hereby; the execution, delivery and performance of this Agreement by Parent and Merger Sub and the consummation of the transactions contemplated hereby have been duly authorized by all necessary corporate action on the part of Parent and Merger Sub; and this Agreement has been duly executed and delivered by Parent and Merger Sub and, assuming this Agreement constitutes a valid and binding obligation of the Stockholder, constitutes a valid and binding obligation of Parent and Merger Sub enforceable against each of them in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies.

5. Further Assurances. The Stockholder will, from time to time, execute and deliver, or cause to be executed and delivered, in each case without further consideration, such additional or further transfers, assignments, endorsements, consents and other instruments as Parent may reasonably request for the purpose of effectively carrying out the Stockholder’s obligations under this Agreement and to vest the power to vote the Securities as contemplated by Section 2. Parent agrees to take, or cause to be taken, (i) all actions reasonably necessary to comply promptly with all legal requirements that may be imposed with respect to the transactions contemplated by this Agreement and (ii) all actions reasonably necessary or desirable to consummate the transactions contemplated by this Agreement.

6. Assignment; Binding Effect. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any of the parties hereto (whether by operation of law or otherwise) without the prior written consent of the other parties, except that Parent may assign all or any of its rights and obligations hereunder to any affiliate of Parent; provided, however, that no such assignment shall relieve the assigning party of its obligations hereunder if such assignee does not perform such obligations. Subject to the preceding sentence, this Agreement shall be binding upon, inure solely to the benefit of, and be enforceable by, the parties hereto and their respective permitted successors and assigns. Notwithstanding anything contained in this Agreement to the contrary, nothing in this Agreement, expressed or implied, is intended to or shall confer on any person other than the parties hereto or their respective heirs, successors, executors, administrators and assigns any rights, benefits, remedies, obligations or liabilities of any nature whatsoever under or by reason of this Agreement.

7. Termination. This Agreement, and all rights and obligations of the parties hereunder, shall terminate upon the first to occur of (i) the Effective Time, (ii) the date on which the Merger Agreement is terminated in accordance with its terms or (iii) the mutual written agreement of the parties to terminate this Agreement. In the event of termination of this Agreement pursuant to this Section 7, this Agreement will become null and void and of no effect with no liability on the part of any party hereto; provided, however, that no such termination will relieve any party hereto from any liability for any willful breach of this Agreement occurring prior to such termination.

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8. Stockholder Capacity. Notwithstanding anything to the contrary in this Agreement, the parties acknowledge that (a) the Stockholder is entering into this Agreement solely in the Stockholder’s capacity as a record and/or beneficial owner of the Company Common Stock and not in such Stockholder’s capacity as a director, officer or employee of the Company (if applicable) or in such Stockholder’s capacity as a trustee or fiduciary of any Plans and (b) nothing in this Agreement is intended to restrict or affect any action or inaction of the Stockholder or any representative of the Stockholder, as applicable, serving on the Company Board or on the board of directors of any Subsidiary of the Company or as an officer or fiduciary of the Company or any Subsidiary of the Company, acting in such Person’s capacity as a director, officer, employee or fiduciary of the Company or any Subsidiary of the Company.

9. General Provisions.

(a) Except as otherwise set forth in the Merger Agreement, all costs and expenses incurred in connection with this Agreement and the transactions contemplated hereby shall be paid by the party incurring such expense, whether or not the transactions contemplated hereby are consummated.

(b) Any provision of this Agreement may be amended or waived if, and only if, such amendment or waiver is in a writing that refers to this Agreement and signed, in the case of an amendment, by each of the parties hereto, or in the case of a waiver, by the party against whom the waiver is to be effective. No failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies provided by applicable law.

(c) Any notice, demand, or communication required or permitted to be given by any provision of this Agreement shall be deemed to have been sufficiently given or served for all purposes if (i) personally delivered, (ii) mailed by registered or certified first-class mail, prepaid with return receipt requested, (iii) sent by a nationally recognized overnight courier service, to the recipient at the address below indicated or (iv) delivered by facsimile or email which is confirmed in writing by sending a copy of such facsimile or email to the recipient thereof pursuant to clause (i) or (iii) above:

If to Parent or Merger Sub:

HeartWare International, Inc.

205 Newbury Street, Suite 101

Framingham, MA 01701

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With a required copy to (which shall not constitute notice):

Shearman & Sterling LLP

599 Lexington Avenue

New York, NY 10022

If to the Stockholder:

At the address and facsimile number and email address set forth set forth in Part I of Exhibit A hereto;

or to such other address as any party hereto may, from time to time, designate in a written notice given in like manner.

(d) When a reference is made in this Agreement to a Section, such reference shall be to a Section of this Agreement unless otherwise indicated. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Wherever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

(e) This Agreement may be executed in one or more counterparts, all of which shall be considered one and the same agreement and shall become effective when two or more counterparts have been signed by each of the parties and delivered to the other parties, it being understood that all parties need not sign the same counterpart. Signatures delivered by facsimile or electronic transmission shall be binding for all purposes hereof.

(f) This Agreement and the Merger Agreement constitute the entire agreement and supersede all prior agreements and understandings, both written and oral, among the parties, or any of them, with respect to the subject matter hereof.

(g) This Agreement shall be governed and construed in accordance with the laws of the State of Delaware without regard to any applicable conflicts of law.

(h) Each party hereto hereby irrevocably and unconditionally submits, for itself and its property, to the exclusive jurisdiction and proper venue of the Court of Chancery of the State of Delaware, and each party consents to personal and subject matter jurisdiction and venue in such courts and waives and relinquishes all right to attack the suitability or convenience of such venue or forum by reason of their present or future domiciles, or by any other reason. The parties acknowledge that all directions issued by the forum court, including all injunctions and other decrees, will be binding and enforceable in all jurisdictions and countries. Each of the parties hereto hereby waives to the fullest extent permitted by applicable Law any right it may have to a trial by jury with respect to any litigation directly or indirectly arising out of, under or in connection with this Agreement or the transactions contemplated hereby.

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(i) If any provision of this Agreement or the application thereof to any party or set of circumstances shall, in any jurisdiction and to any extent, be finally held invalid or unenforceable by any rule of law or public policy, such term or provision shall only be ineffective as to such jurisdiction, and only to the extent of such invalidity or unenforceability, without invalidating or rendering unenforceable any other terms or provisions of this Agreement or under any other circumstances, and the parties shall negotiate in good faith a substitute provision which comes as close as possible to the invalidated or unenforceable term or provision, and which puts each party in a position as nearly comparable as possible to the position it would have been in but for the finding of invalidity or unenforceability, while remaining valid and enforceable.

(j) Each of the parties acknowledges that irreparable damage would occur in the event any provision of this Agreement was not performed in accordance with the terms hereof and agrees that the parties’ respective remedies at law for a breach or threatened breach of any of the provisions of this Agreement would be inadequate and, in recognition of that fact, each agrees that, in the event of a breach or threatened breach by any party of the provisions of this Agreement, in addition to any remedies at law, each party, respectively, without posting any bond, shall be entitled to seek equitable relief in the form of specific performance, a temporary restraining order, a temporary or permanent injunction or any other equitable remedy which may then be available.

[Signature pages follow]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

[Voting Agreement]

Exhibit A

Stockholder Security Ownership and Voting Information

Part I

Part II

Number and Class of Securities held by Stockholder to be voted, pursuant to Section 1(b), in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement, or necessary to the consummation of such transactions, as to which the Company stockholders are called upon to vote, consent or approve:

1,015,286 shares of Company Common Stock

Exhibit 1.4

FINAL VERSION

VOTING AGREEMENT

This Voting Agreement (this “Agreement”) is entered into as of March 29, 2012 among HeartWare International, Inc., a Delaware corporation (“Parent”), Ocean Acquisition Holding Inc., a Delaware corporation and an indirect wholly owned subsidiary of Parent (“Merger Sub”), and the person listed as a stockholder of World Heart Corporation, a Delaware corporation (the “Company”) on the signature page hereto (the “Stockholder”).

RECITALS

A. Concurrently with the execution and delivery of this Agreement, the Company, Merger Sub and Parent are entering into an Agreement and Plan of Merger (as the same may be amended or supplemented, the “Merger Agreement”), which provides, among other things, for the acquisition of the Company by Parent by means of a merger of Merger Sub with and into the Company (the “Merger”), all on the terms and subject to the conditions set forth in the Merger Agreement. Capitalized terms used herein that are not defined shall have the meanings set forth in the Merger Agreement.

B. The Stockholder is the record and beneficial owner of the number of shares of Company Common Stock set forth on Part I of Exhibit A hereto (such securities, as they may be adjusted by stock dividend, stock split, recapitalization, combination or exchange of shares, merger, consolidation, reorganization or other change or transaction of or by the Company, together with securities of the Company that may be acquired after the date hereof by the Stockholder are collectively referred to herein as the “Securities”).

C. As an inducement and a condition to the willingness of Parent and Merger Sub to enter into the Merger Agreement, and in consideration of the substantial expenses incurred and to be incurred by them in connection therewith, the Stockholder has agreed to enter into, be legally bound by and perform this Agreement.

AGREEMENTS

In consideration of the recitals and the representations, warranties, covenants and agreements contained herein, and intending to be legally bound hereby, the parties hereto agree as follows:

1. Covenants of the Stockholder. The Stockholder agrees as follows:

(a) The Stockholder shall not, directly or indirectly, (i) sell, transfer (including by operation of law), pledge, assign or otherwise encumber or dispose of, or enter into any agreement, option or other arrangement (including any profit sharing arrangement) or understanding with respect to any of the Securities to any person other than Parent or Parent’s designee, (ii) deposit any Securities into a voting trust or enter into any voting arrangement, whether by proxy, voting agreement, voting trust, power-of-attorney, attorney-in-fact, agent or otherwise, with respect to the Securities, except as contemplated by this Agreement, or (iii) take any other action that would in any way make any representation or warranty of the Stockholder herein untrue or incorrect in any material respect or otherwise restrict, limit or interfere in any material respect with the performance of the Stockholder’s obligations hereunder or the transactions contemplated hereby.

(b) At any meeting of stockholders of the Company called to vote upon the Merger and the Merger Agreement or at any adjournment thereof or in any other circumstances upon which a vote, consent or other approval (including by written consent) is sought with respect to the Merger and the Merger Agreement, the Stockholder shall vote (or cause to be voted) the number of its Securities set forth in Part II of Exhibit A hereto in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement.

(c) The Stockholder shall take, or cause to be taken, all reasonable actions, and to do, or cause to be done, and to assist and cooperate with the Company and Parent in doing, all things reasonably necessary to consummate and make effective, in the most expeditious manner practicable, the Merger and the other transactions contemplated by the Merger Agreement, including, without limitation, (i) causing the Company to call the Company Stockholders’ Meeting for the purpose of considering, acting upon and voting upon the approval and adoption of the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement (or executing valid and effective written consents in lieu of a meeting of the holders of the minimum number of shares of Company Common Stock required to approve the Merger Agreement, the Merger and all other transactions contemplated by the Merger Agreement), (ii) attending, if applicable, the Company Stockholders’ Meeting or any adjournment thereof (or executing valid and effective proxies to any other attending participant of a Company Stockholders’ Meeting in lieu of attending such Company Stockholders’ Meeting or any adjournment thereof), and (iii) causing the Company to postpone or adjourn, at Parent’s request, the Company Stockholders’ Meeting on one occasion for up to fifteen (15) Business Days (but in any event no later than the Outside Date) (x) in order to solicit additional proxies for the purpose of obtaining the Company Stockholder Approval (unless prior to such adjournment the Company shall have received an aggregate number of proxies voting for the adoption of the Merger Agreement, which have not been withdrawn, such that the condition in Section 8.01(b) of the Merger Agreement will be satisfied at such meeting), (y) if a quorum is not present or (z) in order to allow reasonable additional time for (A) the filing and mailing of, at the reasonable request of Parent, any supplemental or amended disclosure and (B) such supplemental or amended disclosure to be disseminated to, and reviewed by, the stockholders of the Company prior to the Company Stockholders’ Meeting.

(d) The Stockholder shall not, directly or indirectly, through any officer, director, agent or other representative, (i) solicit, initiate or encourage (including by way of furnishing nonpublic information), or take any other action to facilitate, any inquiries or the making of any proposal or offer (including any proposal or offer to the Company’s stockholders) with respect to any Competing Transaction (a “Competing Proposal”) or (ii) enter into, maintain, continue or otherwise engage or participate in any discussions or negotiations with any Person or entity in furtherance of such inquiries or to obtain a proposal or offer with respect to a Competing Transaction. The Stockholder shall, and shall direct or cause its representatives and agents to, immediately cease and cause to be terminated any discussions or negotiations with any parties that may be ongoing with respect to (or that could be reasonably expected to lead to) a Competing Proposal. The Stockholder shall promptly notify Parent, orally and in writing, after the receipt by the Stockholder of any proposal, inquiry, offer or request (or any amendment thereto) with respect to a Competing Transaction including any request for discussions or negotiations. Such notice shall indicate the identity of the Person making such proposal, inquiry, offer or request and a description of such proposal, inquiry, offer or request, including the terms and conditions (if any) of such proposed Competing Transaction.

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(e) The Stockholder shall vote (or cause to be voted) its Securities against (i) any Competing Proposal and (ii) any action, proposal, transaction or agreement which would reasonably be expected to impede, interfere with, delay, discourage, adversely affect or inhibit the timely consummation of the Merger or the fulfillment of Parent’s, the Company’s or Merger Sub’s conditions under the Merger Agreement or change in any manner the voting rights of any security of the Company (including by any amendments to the Company’s charter or bylaws).

2. Grant of Irrevocable Proxy Coupled with an Interest; Appointment of Proxy.

(a) The Stockholder hereby irrevocably (i) grants to Parent and any designee of Parent, alone or together, the Stockholder’s proxy, and (ii) appoints Parent and any designee of Parent as the Stockholder’s proxy, attorney-in-fact and agent (with full power of substitution and resubstitution), alone or together, for and in the name, place and stead of the Stockholder, to vote the Securities, or grant a consent or approval in respect of the Securities, in accordance with Section 1 above at any meeting of the stockholders of the Company or at any adjournment thereof or in any other circumstances upon which their vote, consent or other approval is sought in favor of the Merger, the adoption by the Company of the Merger Agreement and the approval of the other transactions contemplated by the Merger Agreement. The Stockholder agrees to execute such documents or certificates evidencing such proxy as Parent may reasonably request. The Stockholder acknowledges receipt and review of a copy of the Merger Agreement.

(b) The Stockholder represents that any proxies heretofore given in respect of the Securities are not irrevocable, and that any such proxies are hereby revoked.

(c) THE STOCKHOLDER HEREBY AFFIRMS THAT THE PROXY SET FORTH IN THIS SECTION 2 IS COUPLED WITH AN INTEREST AND IS IRREVOCABLE UNTIL SUCH TIME AS THIS AGREEMENT TERMINATES IN ACCORDANCE WITH ITS TERMS. The Stockholder hereby further affirms that the irrevocable proxy is given in connection with the execution of the Merger Agreement, and that such irrevocable proxy is given to secure the performance of the duties of the Stockholder under this Agreement. The Stockholder hereby ratifies and confirms all that such irrevocable proxy may lawfully do or cause to be done by virtue hereof. Such irrevocable proxy shall be valid until the termination of this Agreement in accordance with its terms. The power of attorney granted by the Stockholder is a durable power of attorney and shall survive the bankruptcy, dissolution, death or incapacity of the Stockholder.

3. Representations and Warranties of the Stockholder. The Stockholder hereby represents and warrants to Parent and Merger Sub as follows:

(a) The Stockholder has all requisite power and authority to execute and deliver this Agreement and to perform the Stockholder’s obligations under this Agreement. The execution, delivery and performance of this Agreement have been duly authorized by the Stockholder. This Agreement has been duly executed and delivered by the Stockholder and, assuming this Agreement constitutes a valid and binding obligation of Parent and Merger Sub, constitutes a valid and binding obligation of the Stockholder enforceable against the Stockholder in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies.

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(b) The Securities and the certificates (or any book-entry notations used to represented any uncertificated shares of Company Common Stock) representing the Securities are now, and at all times during the term hereof will be, held by the Stockholder, or by a nominee or custodian for the benefit of the Stockholder, and the Stockholder has title to the Securities, free and clear of any Encumbrances (including voting trusts and voting commitments), except as provided by this Agreement. As of the date of this Agreement, the Stockholder owns of record or beneficially no securities of the Company, or any options, warrants or rights exercisable for securities of the Company, other than the Securities set forth on Part I of Exhibit A hereto. The Stockholder has full power to vote the Securities as provided herein. Neither the Stockholder nor any of the Securities is subject to any voting trust, proxy or other agreement, arrangement or restriction with respect to the voting or disposition of the Securities, except as otherwise contemplated by this Agreement or the Merger Agreement.

(c)(i) No filing with, and no permit, authorization, consent or approval of any state, federal or foreign governmental authority is necessary on the part of the Stockholder for the execution and delivery of this Agreement by the Stockholder and the performance by the Stockholder of the Stockholder’s obligations under this Agreement and (ii) neither the execution and delivery of this Agreement by the Stockholder nor the performance by the Stockholder of the Stockholder’s obligations under this Agreement nor compliance by the Stockholder with any of the provisions hereof shall (x) result in the creation of an encumbrance on any of the Securities or (y) violate any order, writ, injunction, decree, statute, rule or regulation applicable to the Stockholder or any of the Securities, except in the case of (x) or (y) for violations, breaches or defaults that would not in the aggregate materially impair the ability of the Stockholder to perform its obligations hereunder.

(d) The Stockholder understands and acknowledges that Parent and Merger Sub are entering into the Merger Agreement in reliance upon the Stockholder’s execution and delivery of this Agreement.

(e) The Stockholder represents and warrants to Parent and Merger Sub that none of the information relating to the Stockholder and its affiliates provided by or on behalf of the Stockholder or its affiliates for inclusion in the Proxy Statement will, at the respective times that the Proxy Statement is filed with the SEC or is first mailed to the holders of the Company Common Stock, contain any untrue statement of material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. The Stockholder authorizes and agrees to permit Parent and Merger Sub to publish and disclose in the Proxy Statement and any related filings under the securities laws of the United States or any state thereof the Stockholder’s identity and ownership of Securities and the nature of its commitments, arrangements and understandings under this Agreement and any other information required by applicable Law.

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4. Representations and Warranties of Parent and Merger Sub. Parent and Merger Sub hereby jointly and severally represent and warrant to the Stockholder as follows: Parent and Merger Sub have the requisite corporate power and authority to execute and deliver this Agreement and to consummate the transactions contemplated hereby; the execution, delivery and performance of this Agreement by Parent and Merger Sub and the consummation of the transactions contemplated hereby have been duly authorized by all necessary corporate action on the part of Parent and Merger Sub; and this Agreement has been duly executed and delivered by Parent and Merger Sub and, assuming this Agreement constitutes a valid and binding obligation of the Stockholder, constitutes a valid and binding obligation of Parent and Merger Sub enforceable against each of them in accordance with its terms, subject to (i) laws of general application relating to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law governing specific performance, injunctive relief and other equitable remedies.

5. Further Assurances. The Stockholder will, from time to time, execute and deliver, or cause to be executed and delivered, in each case without further consideration, such additional or further transfers, assignments, endorsements, consents and other instruments as Parent may reasonably request for the purpose of effectively carrying out the Stockholder’s obligations under this Agreement and to vest the power to vote the Securities as contemplated by Section 2. Parent agrees to take, or cause to be taken, (i) all actions reasonably necessary to comply promptly with all legal requirements that may be imposed with respect to the transactions contemplated by this Agreement and (ii) all actions reasonably necessary or desirable to consummate the transactions contemplated by this Agreement.

6. Assignment; Binding Effect. Neither this Agreement nor any of the rights, interests or obligations hereunder shall be assigned by any of the parties hereto (whether by operation of law or otherwise) without the prior written consent of the other parties, except that Parent may assign all or any of its rights and obligations hereunder to any affiliate of Parent; provided, however, that no such assignment shall relieve the assigning party of its obligations hereunder if such assignee does not perform such obligations. Subject to the preceding sentence, this Agreement shall be binding upon, inure solely to the benefit of, and be enforceable by, the parties hereto and their respective permitted successors and assigns. Notwithstanding anything contained in this Agreement to the contrary, nothing in this Agreement, expressed or implied, is intended to or shall confer on any person other than the parties hereto or their respective heirs, successors, executors, administrators and assigns any rights, benefits, remedies, obligations or liabilities of any nature whatsoever under or by reason of this Agreement.

7. Termination. This Agreement, and all rights and obligations of the parties hereunder, shall terminate upon the first to occur of (i) the Effective Time, (ii) the date on which the Merger Agreement is terminated in accordance with its terms or (iii) the mutual written agreement of the parties to terminate this Agreement. In the event of termination of this Agreement pursuant to this Section 7, this Agreement will become null and void and of no effect with no liability on the part of any party hereto; provided, however, that no such termination will relieve any party hereto from any liability for any willful breach of this Agreement occurring prior to such termination.

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8. Stockholder Capacity. Notwithstanding anything to the contrary in this Agreement, the parties acknowledge that (a) the Stockholder is entering into this Agreement solely in the Stockholder’s capacity as a record and/or beneficial owner of the Company Common Stock and not in such Stockholder’s capacity as a director, officer or employee of the Company (if applicable) or in such Stockholder’s capacity as a trustee or fiduciary of any Plans and (b) nothing in this Agreement is intended to restrict or affect any action or inaction of the Stockholder or any representative of the Stockholder, as applicable, serving on the Company Board or on the board of directors of any Subsidiary of the Company or as an officer or fiduciary of the Company or any Subsidiary of the Company, acting in such Person’s capacity as a director, officer, employee or fiduciary of the Company or any Subsidiary of the Company.

9. General Provisions.

(a) Except as otherwise set forth in the Merger Agreement, all costs and expenses incurred in connection with this Agreement and the transactions contemplated hereby shall be paid by the party incurring such expense, whether or not the transactions contemplated hereby are consummated.

(b) Any provision of this Agreement may be amended or waived if, and only if, such amendment or waiver is in a writing that refers to this Agreement and signed, in the case of an amendment, by each of the parties hereto, or in the case of a waiver, by the party against whom the waiver is to be effective. No failure or delay by any party in exercising any right, power or privilege hereunder shall operate as a waiver thereof nor shall any single or partial exercise thereof preclude any other or further exercise thereof or the exercise of any other right, power or privilege. The rights and remedies herein provided shall be cumulative and not exclusive of any rights or remedies provided by applicable law.

(c) Any notice, demand, or communication required or permitted to be given by any provision of this Agreement shall be deemed to have been sufficiently given or served for all purposes if (i) personally delivered, (ii) mailed by registered or certified first-class mail, prepaid with return receipt requested, (iii) sent by a nationally recognized overnight courier service, to the recipient at the address below indicated or (iv) delivered by facsimile or email which is confirmed in writing by sending a copy of such facsimile or email to the recipient thereof pursuant to clause (i) or (iii) above:

If to Parent or Merger Sub:

HeartWare International, Inc.

205 Newbury Street, Suite 101

Framingham, MA 01701

With a required copy to (which shall not constitute notice):

Shearman & Sterling LLP

599 Lexington Avenue

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If to the Stockholder:

At the address and facsimile number and email address set forth set forth in Part I of Exhibit A hereto;

or to such other address as any party hereto may, from time to time, designate in a written notice given in like manner.

(d) When a reference is made in this Agreement to a Section, such reference shall be to a Section of this Agreement unless otherwise indicated. The headings contained in this Agreement are for reference purposes only and shall not affect in any way the meaning or interpretation of this Agreement. Wherever the words “include,” “includes” or “including” are used in this Agreement, they shall be deemed to be followed by the words “without limitation.”

(e) This Agreement may be executed in one or more counterparts, all of which shall be considered one and the same agreement and shall become effective when two or more counterparts have been signed by each of the parties and delivered to the other parties, it being understood that all parties need not sign the same counterpart. Signatures delivered by facsimile or electronic transmission shall be binding for all purposes hereof.

(f) This Agreement and the Merger Agreement constitute the entire agreement and supersede all prior agreements and understandings, both written and oral, among the parties, or any of them, with respect to the subject matter hereof.

(g) This Agreement shall be governed and construed in accordance with the laws of the State of Delaware without regard to any applicable conflicts of law.

(h) Each party hereto hereby irrevocably and unconditionally submits, for itself and its property, to the exclusive jurisdiction and proper venue of the Court of Chancery of the State of Delaware, and each party consents to personal and subject matter jurisdiction and venue in such courts and waives and relinquishes all right to attack the suitability or convenience of such venue or forum by reason of their present or future domiciles, or by any other reason. The parties acknowledge that all directions issued by the forum court, including all injunctions and other decrees, will be binding and enforceable in all jurisdictions and countries. Each of the parties hereto hereby waives to the fullest extent permitted by applicable Law any right it may have to a trial by jury with respect to any litigation directly or indirectly arising out of, under or in connection with this Agreement or the transactions contemplated hereby.

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(i) If any provision of this Agreement or the application thereof to any party or set of circumstances shall, in any jurisdiction and to any extent, be finally held invalid or unenforceable by any rule of law or public policy, such term or provision shall only be ineffective as to such jurisdiction, and only to the extent of such invalidity or unenforceability, without invalidating or rendering unenforceable any other terms or provisions of this Agreement or under any other circumstances, and the parties shall negotiate in good faith a substitute provision which comes as close as possible to the invalidated or unenforceable term or provision, and which puts each party in a position as nearly comparable as possible to the position it would have been in but for the finding of invalidity or unenforceability, while remaining valid and enforceable.

(j) Each of the parties acknowledges that irreparable damage would occur in the event any provision of this Agreement was not performed in accordance with the terms hereof and agrees that the parties’ respective remedies at law for a breach or threatened breach of any of the provisions of this Agreement would be inadequate and, in recognition of that fact, each agrees that, in the event of a breach or threatened breach by any party of the provisions of this Agreement, in addition to any remedies at law, each party, respectively, without posting any bond, shall be entitled to seek equitable relief in the form of specific performance, a temporary restraining order, a temporary or permanent injunction or any other equitable remedy which may then be available.

[Signature pages follow]

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement as of the date first written above.

[Voting Agreement]

Exhibit A

Stockholder Security Ownership and Voting Information

Part I

Part II

Number and Class of Securities held by Stockholder to be voted, pursuant to Section 1(b), in favor of the Merger, the adoption of the Merger Agreement and the approval of the terms thereof and each of the other transactions contemplated by this Agreement or the Merger Agreement, or necessary to the consummation of such transactions, as to which the Company stockholders are called upon to vote, consent or approve:

Exhibit 1.5

JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13D, dated April 5, 2012 (the “Schedule 13D”), with respect to the common stock, par value $.001 per share, of World Heart Corporation is, and any amendments thereto executed by each of us shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities and Exchange Act of 1934, as amended, and that this Agreement shall be included as an exhibit to the Schedule 13D and each such amendment. Each of the undersigned agrees to be responsible for the timely filing of the Schedule 13D and any amendments thereto, and for the completeness and accuracy of the information concerning itself contained therein. This Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.