Item 4.01. Changes in Registrant's Certifying Accountant (a) Dismissal of Independent Registered Public Accounting Firm On March 30, 2026, the Audit Committee of the Board of Directors (the “ Audit Committee”) of iRhythm Holdings, Inc. (the “ Company”) dismissed PricewaterhouseCoopers LLP (“ PwC”) as the Company’s independent registered public accounting firm. PwC’s audit reports on the Company’s consolidated financial statements for the fiscal years ended December 31, 2025 and December 31, 2024 did not contain an adverse opinion or a disclaimer of opinion and were not qualified or modified as to uncertainty, audit scope, or accounting principles. During the Company’s two most recent fiscal years ended December 31, 2025 and December 31, 2024, and the subsequent interim period through March 30, 2026, (i) there were no “disagreements” (within the meaning set forth in Item 304(a)(1)(iv) of Regulation S-K) between the Company and PwC on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which disagreements, if not resolved to PwC’s satisfaction, would have caused PwC to make reference to the subject matter of the disagreements in connection with their reports; and (ii) there were no “reportable events” (within the meaning set forth in Item 304(a)(1)(v) of Regulation S-K). In accordance with Item 304(a)(3) of Regulation S-K, the Company provided PwC with a copy of this Current Report on Form 8-K and requested that PwC furnish it with a letter addressed to the U. S. Securities and Exchange Commission stating whether PwC agrees with the statements of the Company herein and, if not, stating the respects in which it does not agree. PwC furnished the requested letter, stating its agreement with such statements, and a copy is filed as Exhibit 16.1 to this Current Report on Form 8-K. (b) Engagement of New Independent Registered Public Accounting Firm On March 30, 2026, the Audit Committee approved the engagement of KPMG LLP (“ KPMG”) as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026. During the Company’s two most recent fiscal years and the subsequent interim period through March 30, 2026, neither the Company, nor anyone on its behalf, consulted KPMG regarding (i) the application of accounting principles to a specific transaction, either completed or proposed, or the type of audit opinion that might be rendered on the Company’s financial statements, and neither a written report nor oral advice was provided to the Company that KPMG concluded was an important factor considered by the Company in reaching a decision as to any accounting, auditing, or financial reporting issue, or (ii) any matter that was either the subject of a "disagreement" (within the meaning set forth in Item 304(a)(1)(iv) of Regulation S-K and the related instructions to Item 304 of Regulation S-K) or a "reportable event" (within the meaning set forth in Item 304(a)(1)(v) of Regulation S-K).

Item 9.01 Financial Statements and Exhibits (d) Exhibits Exhibit No. Description 16.1 Letter from PricewaterhouseCoopers LLP dated March 31, 2026. ───────────────────────────────────────────────────────────────────────────────── 104 Cover Page Interactive Data File (formatted as Inline XBRL) SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. IRHYTHM HOLDINGS, INC. Date: March 31, 2026 By: /s/ Daniel Wilson Daniel Wilson Chief Financial Officer