CUSIP No. 450056106 13G Page 1 5 of 19 Pages

EXHIBIT 1

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of shares of Common Stock of iRhythm Technologies, Inc.

Date: February 10, 2017

NEW LEAF VENTURES II, L.P.
By:	NEW LEAF VENTURE ASSOCIATES II, L.P.
	General Partner
	By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
		General Partner
		By:	*
			Craig L. Slutzkin
			Chief Financial Officer
NEW LEAF VENTURE ASSOCIATES II, L.P.
By:	NEW LEAF VENTURE MANAGEMENT II, L.L.C.
	General Partner
	By:	*
		Craig L. Slutzkin
		Chief Financial Officer
NEW LEAF VENTURE MANAGEMENT II, L.L.C.
By:	*
	Craig L. Slutzkin
	Chief Financial Officer
*
Philippe O. Chambon
*
Vijay Lathi
*
Ronald Hunt

CUSIP No. 450056106 13G Page 16 of 19 Pages

        *

Jeani Delagardelle

        *

Liam Ratcliffe

/s/ Craig L. Slutzkin

Craig L. Slutzkin

As attorney-in-fact

* This Schedule 13G was executed by Craig L. Slutzkin on behalf of the individuals listed above pursuant to Powers of Attorney, copies of which are attached as Exhibit 2.