Olgin JE, et al. - Given that implantable cardioverter-defibrillators are contraindicated until 40-90 days following myocardial infarction (MI; despite the high rate of sudden death following MI among patients with a low ejection fraction), researchers examined whether a wearable cardioverter-defibrillator would decrease the incidence of sudden death during this high-risk period. Data indicated that the wearable cardioverter-defibrillator did not reduce the rate of the primary outcome of arrhythmic death than control among patients with a recent MI and an ejection fraction of ≤ 35%.

Methods

• Researchers randomized (in a 2:1 ratio) study participants with acute MI and an ejection fraction of ≤ 35% to receive a wearable cardioverter-defibrillator in combination with guideline-directed therapy (the device group) or to receive only guideline-directed therapy (the control group).
• The composite of sudden death or death from ventricular tachyarrhythmia at 90 days (arrhythmic death) was the primary outcome.
• Death from any cause and nonarrhythmic death were the included secondary outcomes.

Results

• Of 2,302 study participants, 1,524 were randomized to the device group and 778 to the control group.
• In the device group, participants wore the device for a median of 18.0 hours per day (interquartile range, 3.8 to 22.7).
• Researchers reported that arrhythmic death occurred in 1.6% of the participants in the device group and in 2.4% of those in the control group (relative risk, 0.67; 95% confidence interval [CI], 0.37 to 1.21; P=0.18).
• They found that death from any cause occurred in 3.1% of the participants in the device group and in 4.9% of those in the control group (relative risk, 0.64; 95% CI, 0.43 to 0.98; uncorrected P=0.04), and nonarrhythmic death occurred in 1.4% and 2.2%, respectively (relative risk, 0.63; 95% CI, 0.33 to 1.19; uncorrected P=0.15).
• Among the participants in the device group who died (n=48), 12 were wearing the device at the time of death.
• An aggregate of 20 study participants in the device group (1.3%) received an appropriate shock, and 9 (0.6%) received an inappropriate shock.