MAUDE Adverse Event Report: IRHYTHM TECHNOLOGIES, INC ZIO AT; DETECTOR AND ALARM, ARRHYTHMIA

Medical Device Problem Code	Failure to Transmit Record (1521)
Health Effect - Clinical Code	Unspecified Heart Problem (4454)
Date of Event	05/26/2026
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
The device was returned to irhythm, and the clinical data was downloaded.A review of the clinical data revealed the device was worn for 13 days of the 14-day prescribed wear period.The hcp account was notified on day 5 that the device was approaching the asymptomatic transmission limit, and a replacement device was shipped.The device reached the asymptomatic maximum transmission limit and stopped transmitting asymptomatic events on day 7.Irhythm became aware of the arrhythmia while preparing final report and notified the hcp on day 20.As described in product labeling, the zio at device has a maximum threshold of transmitting 100 patient triggers and 500 asymptomatic transmissions during wear.When a patient is approaching the limit for either transmission type, irhythm reaches out to the account to determine whether to send another at device to the patient.Patient-triggered symptomatic transmissions are still able to be transmitted beyond this limit by pressing the large central button located on the outer device housing.The transmission limit counter is reflected on daily reports available to the hcp and in the zio suite portal.This event is being reported per 21cfr 803 as a product problem /malfunction.This report does not constitute an admission by irhythm that the product described in this report has any defects or has malfunctioned.These terms are included in form fda 3500a and are fixed terms for selection created by the fda to categorize the type of event solely for the purpose of regulatory reporting.
Event or Problem Description
The patient experienced an arrhythmia that met medical doctor notification (mdn) requirements that was not transmitted during the wear period.The investigation confirmed the zio at reached the asymptomatic maximum transmission limit.The healthcare provider (hcp) account was notified that the device was approaching the asymptomatic transmission limit prior to reaching the limit, according to the standard process, and a replacement device was shipped.No adverse events, such as death or serious injury, are known to have occurred.

• Brand Name: ZIO AT
• Common Device Name: DETECTOR AND ALARM, ARRHYTHMIA
• Manufacturer (Section D): IRHYTHM TECHNOLOGIES, INC; 699 8th st suite 600; san francisco CA 94103
• Manufacturer (Section G): IRHYTHM TECHNOLOGIES, INC; 6550 katella avenue, suite 200; cypress CA 90630
• Manufacturer Contact: tara mackinnon ; 699 8th st suite 600; san francisco, CA 94103 ; 6094600577
• MDR Report Key: 25638965
• Report Number: 3007208829-2026-00200
• Device Sequence Number: 9353223
• Product Code: QYX
• UDI-Device Identifier: 00869770000210
• UDI-Public: (01)00869770000210(17)260930
• Combination Product (Y/N): N
• Initial Reporter State: CA
• Initial Reporter Country: US
• PMA/510(K) Number: K240117
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Company Representative
• Initial Reporter Occupation: Non-Healthcare Professional
• Type of Report: Initial
• Report Date (Section B): 06/26/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Lay User/Patient
• Device Expiration Date: 09/30/2026
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 06/01/2026
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 06/03/2026
• Initial Report FDA Received Date: 06/26/2026
• Was Device Evaluated by Manufacturer? (Y/N): Yes
• Date Device Manufactured: 04/03/2026
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Patient Age: 87 YR
• Patient Sex: Male