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ZOLL LifeVest Wearable Defibrillator

The LifeVest wearable defibrillator is the first and only wearable defibrillator for patients at high risk of sudden cardiac arrest (SCA). The authors noted that current guidelines do not address the routine use of WCDs such as the LifeVest® (Zoll Medical Corp., Chelmsford, MA, USA) in patients with syncope.” 1 While this is true, the authors ask us to take a common-sense approach appealing to the Bayes theorem and the pretest probability that the patient's recurrent symptomatic events were driven by a malignant arrhythmia despite a normal echo and no significant obstructive coronary disease at catheterization.
A study last summer showed that use of the vests by patients who had previously had a heart attack reduced all-cause mortality but not mortality Wearable Defibrillator from sudden cardiac death Investigators, however, speculated that misclassification of some deaths could be responsible for the odd result.

We randomly assigned (in a 2:1 ratio) patients with acute myocardial infarction and an ejection fraction of 35% or less to receive a wearable cardioverter-defibrillator plus guideline-directed therapy (the device group) or to receive only guideline-directed therapy (the control group).
For example, patients who have had large myocardial infarctions or undergone coronary revascularization with decreased left ventricular function (LVEF ++<++ 30%) may be candidates for ICD implantation if their ventricular function does not improve after 1 or 3 months, respectively (MADIT-2 criteria).

The Vest Prevention of Early Sudden Death Trial and VEST Registry (VEST) study was negative for the reduction of sudden cardiac death (SCD) in the postmyocardial-infarction waiting” period, but was likely underpowered and had a protracted enrollment period, during which time, the enrollment target was reduced.
When focusing only on studies that involved patients with ischaemic cardiomyopathy, they found the incidence of appropriate WCD therapy to be much lower in the VEST trial at only 1 per 100 people over 3 months (95% CI: 1.0 to 2.0) than in the observational studies, which had an incidence of 11 per 100 people over 3 months (95% CI: 11.0 to 20.0; I2=93%).

The FDA believes that the new, more prominent and persistent patient alert for Message Code 102” will help increase awareness of the potential hazard and increase the likelihood of a patient contacting Zoll immediately for a replacement device after the alert appears on the device screen.
Patients have sometimes reported that they find the device symbolic of their own vulnerability 33 Of course, such adverse emotions may occur in all patients facing the sudden news that they have a serious cardiovascular condition regardless of whether they are prescribed a WCD or some other therapy.

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