MAUDE Adverse Event Report: ZOLL MANUFACTURING CORPORATION LIFEVEST WCD 4000 SYSTEM; WEARABLE CARDIOVERTER DEFIBRILLATOR

Model Number	LIFEVEST WCD 4000 SYSTEM
Medical Device Problem Code	Incorrect Interpretation of Signal (1543)
Health Effect - Clinical Code	Arrhythmia (1721)
Date of Event	03/22/2026
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
The monitor and electrode belt have not been returned for evaluation.Based on the data available at this time, there is no indication of a device malfunction causing or contributing to the inappropriate treatment.Inappropriate defibrillations are an anticipated risk associated with the use of the lifevest.Patients are instructed through alarms, voice messages, ifu, and training to press the response buttons to prevent an inappropriate defibrillation.The current commercial inappropriate defibrillation rate is consistent with the observed rate during the pivotal clinical trial (b)(4) (0.69% per patient-month with 90% confidence).A summary of the safety and effectiveness data (ssed), including the inappropriate defibrillation safety objective supporting fda's approval of the lifevest, can be found at http://www.Accessdata.Fda.Gov/cdrh_docs/pdf/p010030b.Pdf.
Event or Problem Description
A patient received an inappropriate shock.Oversensing of cardiac activity contributed to the false detection.The response buttons were pressed after the event.Patient was taken to the hospital, will continue to wear the lifevest until icd scheduled on (b)(6) 2026.

• Brand Name: LIFEVEST WCD 4000 SYSTEM
• Common Device Name: WEARABLE CARDIOVERTER DEFIBRILLATOR
• Manufacturer (Section D): ZOLL MANUFACTURING CORPORATION; 121 gamma drive; pittsburgh PA 15238
• Manufacturer (Section G): ZOLL MANUFACTURING CORPORATION; 121 gamma drive; pittsburgh PA
• Manufacturer Contact: zoll mfg corporation ; 121 gamma drive; pittsburgh, PA 15238
• MDR Report Key: 24741096
• Report Number: 3008642652-2026-03090
• Device Sequence Number: 14764016
• Product Code: MVK
• UDI-Device Identifier: 00855778005005
• UDI-Public: (01)00855778005005(11)250114
• Combination Product (Y/N): N
• Initial Reporter State: PA
• Initial Reporter Country: US
• PMA/510(K) Number: P010030
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Distributor
• Initial Reporter Occupation: Other
• Type of Report: Initial
• Report Date (Section B): 03/31/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Operator of Device: Lay User/Patient
• Device Model Number: LIFEVEST WCD 4000 SYSTEM
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 03/31/2026
• Initial Report FDA Received Date: 03/31/2026
• Is the Device Labeled for Single Use? (Y/N): No
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Reuse
• Patient Sequence Number: 1
• Patient Sex: Unknown