FDA alert raises concerns over safety of wearable cardioverter defibrillator

zoll lifevest 4000
LifeVest 4000 (Zoll) wearable cardioverter defibrillator

The US Food and Drug Administration (FDA) is providing information and recommendations regarding the Zoll LifeVest 4000 due to concerns that the device may fail to deliver treatment to the patient if the device is not replaced soon after displaying an onscreen alert. When functioning as intended, patients with ventricular tachycardia or fibrillation showed a 92% survival rate in a 2016 prospective registry study.

The alert reads, “Call for service: Device has a problem that may require service. Call ZOLL for service, Message Code 102.” Failure to contact Zoll and immediately replace the device after Message Code 102 appears on the device screen may result in serious patient harm or death of the patient, the FDA say in a safety communication, because the device may fail to deliver therapy appropriately when needed.

Ideally, the LifeVest monitors the patient’s heart, delivering automatic emergency defibrillation as needed to restore sinus rhythm. However, the FDA is aware that in certain cases the LifeVest 4000 may not be able to deliver the treatment shock to a patient due to a fault that prevents the device from charging its high-energy capacitors. During normal operation, this fault prompts the LifeVest to display the alert to call Zoll for service. The “Message Code 102” alert does not however indicate explicitly to the patient that the device cannot be used and that the patient should call the company immediately.

To date, the FDA reports it is aware of one patient death due to the LifeVest’s failure to deliver treatment as expected after Message Code 102 was displayed. According to Zoll,  as of 14 November 2017, there were a total of 33,670 devices distributed, with 24,975 devices distributed in the U.S. About 0.1% of the total devices distributed have displayed Message Code 102, which should only be remedied by immediate replacement of the device.

The FDA will continue to work with Zoll to monitor LifeVest 4000 devices for any adverse events related to Message Code 102 or a failure to deliver treatment. The FDA states it will also continue to work with Zoll to identify a permanent solution to the Message Code 102 issue, keeping the public informed as new information becomes available.


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