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

Model Number WCD 4000

Device Problems Defibrillation/Stimulation Problem (1573); Inappropriate/Inadequate Shock/Stimulation (1574)

Patient Problem Shock from Patient Lead(s) (3162)

Event Date 11/20/2020

Event Type  Injury  

Manufacturer Narrative

Explanation: there was no death or serious injury associated with the inappropriate defibrillation event.Device evaluation summary: monitor sn (b)(4) and electrode belt sn (b)(4) were returned and evaluated at the distributor, in accordance with procedures recommended by zoll manufacturing corporation.The evaluation included review of downloaded software flag files and ecg strips on the day of the event and incoming functional testing.The software flag files revealed a shock occurred during the time in question and the response button was not depressed.Review of the ecg strip showed that at the time of the shock there was motion artifact and af over the patient's physician prescribed treatment threshold.Additionally, incoming functional testing was conducted on the suspect device.During functional testing, a 1hz simulated normal sinus rhythm signal was applied to the ecg electrodes, followed by a 5hz simulated treatable arrhythmia signal which verified proper performance of the detection algorithm.During the transition to the 5hz signal, the device was confirmed to properly enter into a treatment sequence which includes a verification of the tactile vibration alarm, audio messaging, and siren alarms, as well as a test of the pulse delivery circuitry.The pulse delivery circuitry test verified proper charging of the high voltage capacitors and proper delivery of five full energy 150j biphasic pulses.The functional testing confirmed proper response button functionality, ecg acquisition, detection algorithm performance, and pulse delivery functionality.The investigation into the event concludes that there was no device malfunction.A cause and effect analysis was conducted using all of the available information which includes the incident report, device evaluation, software flag files, and ecg strips (attached).The primary cause of the inappropriate shock was lack of response button use prior to shock delivery.The response buttons were not pressed during the event.The ecg analysis, conducted by trained ecg technicians, identified the primary cause of the false detection was af with rvr and motion artifact.The source of the artifact could not be positively identified through cause and effect analysis (90e0012_a09_revfi).The following could not be ruled out as contributing factors: body motion, poor ecg contact with skin, rate exceeds programmed threshold, ecg morphology change, patient error - did not follow training or respond to ifus, alarms, voice prompts.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.The lifevest detection algorithm complies with iec 60601-2-4 performance requirements for sensitivity and specificity.

Event Description

A us distributor contacted zoll to report that a patient experienced an inappropriate defibrillation event consisting of two shocks.The patient was reportedly conscious and using a chainsaw at the time of the event.Atrial fibrillation (af) with a rapid ventricular response (rvr) and motion artifact contributed to the false detection.The response buttons were not pressed during the event.The patient did not seek medical attention after the event and the patient continues wearing the lifevest.There was no death or device malfunction associated with the inappropriate defibrillation event.

• Brand Name: LIFEVEST WCD 4000 SYSTEM
• Type of Device: WEARABLE CARDIOVERTER DEFIBRILLATOR
• Manufacturer (Section D): ZOLL MANUFACTURING CORPORATION; 121 gamma drive; pittsburgh PA 15238 3495
• Manufacturer (Section G): ZOLL MANUFACTURING CORPORATION; 121 gamma drive; pittsburgh PA 15238 3495
• Manufacturer Contact: mary ward ; 121 gamma drive; pittsburgh, PA 15238-3495 ; 4129683333
• MDR Report Key: 11125597
• MDR Text Key: 225524170
• Report Number: 3008642652-2021-00068
• Device Sequence Number: 1
• Product Code: MVK
• UDI-Device Identifier: 00855778005005
• UDI-Public: 00855778005005
• Combination Product (y/n): N
• Reporter Country Code: US
• PMA/PMN Number: P010030
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: distributor
• Reporter Occupation: Other
• Type of Report: Initial
• Report Date: 01/06/2021

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 01/06/2021
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Lay User/Patient
• Device Model Number: WCD 4000
• Device Catalogue Number: 10A0988
• Was Device Available for Evaluation?: Yes
• Date Manufacturer Received: 12/07/2020
• Was Device Evaluated by Manufacturer?: Device Not Returned to Manufacturer
• Date Device Manufactured: 10/02/2018
• Is the Device Single Use?: No
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Reuse
• Patient Sequence Number: 1
• Patient Outcome(s): Other