Wearable cardioverter defibrillator offers automatic arrhythmia treatment

An FDA-approved wearable cardioverter defibrillator is available for patients at risk for sudden cardiac arrest.

According to a press release, the LifeVest (Zoll Lifecor Corp.) is the first wearable cardioverter defibrillator. The device consists of an electrode belt attached to a garment worn around the patient’s chest and a monitor that the patient wears around the waist. The entire system weighs 1.8 lb, making it the lightest defibrillator.

The patient’s baseline vector cardiogram is used as the template for arrhythmia detection. Once an arrhythmia has been detected, the LifeVest system begins a 30-second mechanical cycle that consists of a series of audible alarms and warnings to the patient and those in the immediate area. After 20 seconds, the electrodes, which are in contact with the patient’s skin, secrete gel and deliver the appropriate electrical charge to the patient. If the patient responds to the shock at any time, the system will stop. Depending on the patient response, the device will repeat the delivery of the electrical current up to five times.

The LifeVest can detect ventricular tachycardia (95% sensitivity) and ventricular fibrillation (100% sensitivity). Investigators are currently enrolling patients in the Vest Prevention of Early Sudden Death (VEST) trial, to be followed up with the Prediction of ICD Therapies Study (PREDICT) trial. The investigators are planning to enroll an estimated 4,500 patients admitted to hospitals with an acute MI and with left ventricular ejection fraction >35%. The study will consist of an experimental arm in which patients will be assigned to wear the device for two to three months and of a non-intervention arm in which patients receive typical recommended treatment. – by Eric Raible