Wearable Cardioverter-Defibrillator Use in Patients Perceived to Be at High Risk Early Post Myocardial Infarction

Study Questions:

What are the outcomes of post-infarction patients who receive a wearable cardioverter-defibrillator (WCD) while waiting the mandated 40 days (or 3 months if revascularization has been performed) for an implantable cardioverter-defibrillator (ICD)?

Methods:

This was a retrospective analysis of patients with recent myocardial infarction (MI) and an ejection fraction (EF) ≤35% who received a WCD. The data were obtained from the WCD manufacturer’s database.

Results:

A WCD was used by 8,453 post-infarction patients (mean age 62.7 years) for a mean of 69 days (median daily use 21.8 hours). Appropriate WCD shocks were delivered in 133 patients (1.6%). Post-shock mortality was 9%. Inappropriate shocks occurred in 99 patients (1.2%). The median time from WCD prescription to first appropriate shock was 9 days. Twelve-month survival was 65% in patients who received an appropriate shock, compared to 93% for all patients who used the WCD.

Conclusions:

A small percentage of post-infarction patients benefit from the use of a WCD while waiting the mandated 40 days (or 3 months if revascularization has been performed) for an ICD.

Perspective:

The 1.6% incidence of appropriate WCD shocks in this study is consistent with the results of the VALIANT trial, in which there was a 1.4% incidence of sudden death/cardiac arrest in the first 30 days after MI complicated by a low EF or heart failure. However, two randomized trials (DINAMIT and IRIS) demonstrated no survival benefit of the ICD for high-risk patients when implanted early (5-40 days) post-infarction. An ongoing clinical trial (VEST Prevention of Early Sudden Death) should be helpful in clarifying whether early post-infarction use of the WCD improves survival.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: Risk, Myocardial Infarction, Ventricular Function, Left, Shock, Electric Countershock, Ventricular Fibrillation, Valine, Tetrazoles, Incidence, Nephrotic Syndrome, Myocardial Revascularization, Cardiovascular Diseases, Stroke Volume, Defibrillators, Implantable, Death, Sudden, Cardiac


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