Shock talk: Heart experts debate benefits of ‘LifeVest’

The best laid plans of mice, men – and biotech engineering companies – sometimes go awry.

Take, for example, the Zoll LifeVest, a wearable defibrillator designed and engineered to be worn by heart patients at risk for sudden cardiac arrest.

Dr. Daniel Wubneh, a personable and erudite cardiologist with the Indian River Medical Center, says “I think it’s a great tool for the right patient,” but he freely admits it’s not for everyone and is also quick to point out there seem to be at least some flaws in the product.

Zoll Medical Group, located in Pittsburgh, Pa., is a subsidiary of the Asahi Kasei Group. Its LifeVest first garnered FDA approval in 2001 and has been continuously updated since.

According to the Cleveland Clinic, “there are two main components to the LifeVest: a garment and a monitor. The lightweight garment is worn under clothing and contains electrodes to pick up the patient’s electrocardiogram or ECG. The monitor, about the size of a paperback book, is worn around the waist like a fanny pack or from a shoulder strap.

“The monitor reads the patient’s ECG continuously. If the patient has ventricular tachycardia (rapid heartbeat) or ventricular fibrillation (rapid, uncontrolled, ineffective heartbeat), the device sounds an alarm to verify that the patient is non-responsive. If the patient is conscious, the patient has time to respond to the alarms by pressing two buttons to stop the treatment sequence. If the patient does not respond, the device warns bystanders that a shock is about to be delivered. If the arrhythmia continues and the patient still does not respond, a treatment shock is delivered through the garment electrodes.”

That shock, according to Wubneh, is “between 150 and 200 joules.”

Zoll says “the LifeVest is used for a wide range of patient conditions or situations, including following a heart attack, before or after bypass surgery or stent placement, as well as for those with cardiomyopathy or congestive heart failure that places them at particular risk,” and Wubneh can vouch for at least one case in which it performed flawlessly.

“I recently had a patient a few weeks ago,” Wubneh explains, “who was visiting from out of town. A lovely woman who was on vacation here and she had just been fitted in a vest about a month or maybe two months prior to her coming here. She had what she thought [was] a single episode [in which] she had just passed out. But she actually had ventricular fibrillation arrest. Cardiac arrest. And it took about 45 seconds [for her LifeVest] to deliver the appropriate shocks. She was defibrillated twice. And she regained spontaneous circulation and became coherent and came to the hospital and we were able to treat her and she walked out of here.”

That said, other news in 2018 has been less kind to Zoll’s LifeVest.

In a January article, MedCityNews reported “a patient who died when a Zoll LifeVest failed to work has led the manufacturer Zoll Medical and the FDA to issue a safety alert for physicians and patients using the wearable heart monitor and external defibrillator.”

The FDA said “ideally, the LifeVest monitors the patient’s heart, delivering a treatment shock as needed to restore the patient’s heartbeat to a normal rhythm.”

However, it went on to say, “it is aware that in certain cases the LifeVest 4000 may not be able to deliver a life-saving treatment shock to a patient due to a fault that prevents the device from charging its high-energy capacitors.”

The news was worse in March.

An article on FierceBioTech, a website endorsed by the Massachusetts Institute of Technology Department of Biological Engineering, stated “a phase-three trial of Zoll Medical’s LifeVest has missed its primary endpoint.

“The study found that people who started using the wearable defibrillator the week after they had a heart attack were just as likely to suffer sudden cardiac death in the next three months as patients who received conventional therapy.”

While Wubneh sees the potential benefits of this high-tech device, he insists “I think the decision on who should wear [these vests] should be a shared patient-physician decision,” adding “it needs to be on the right patient.”

Is there an easy answer to what constitutes “the right patient”?

No. But Wubneh contends that patients should work with their cardiologist and then decide for themselves. After all, they are the ones who have a “vested” interest in the outcome.

“I will say,” Wubneh concludes, “speaking as a physician, there are [doctors] who are on both sides of this argument.

“I think it seems that those who have experienced a patient being saved by [these vests] seem to be a little bit more in the camp of support for it,” but ultimately, it’s the patients’ decision to make.


Dr. Daniel Wubneh is with the Indian River Medical Center. His office is at 3450 11th Court, Suite 102. The phone number is 772-778-8687.  

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