Use of the Wearable Cardioverter-Defibrillator Among Patients With Myocarditis and Reduced Ejection Fraction or Ventricular Tachyarrhythmia: Data From a Multicenter Registry

Abstract

Background Data on the use of the wearable cardioverter-defibrillator (WCD) among patients with myocarditis remain sparse. Consequently, evidence for guideline recommendations in this patient population is lacking. Methods and Results In total, 1596 consecutive patients were included in a multicenter registry from 8 European centers, with 124 patients (8%) having received the WCD due to myocarditis and reduced left ventricular ejection fraction or prior ventricular tachyarrhythmia. The mean age was 51.6±16.3 years, with 74% being male. Patients were discharged after index hospitalization on heart failure medication: Angiotensin-converting enzyme inhibitors (62.5%), angiotensin-receptor-neprilysin inhibitor (22.9%), aldosterone-antagonists (51%), or beta blockers (91.4%). The initial median left ventricular ejection fraction was 30% (22%-45%) and increased to 48% (39%-55%) over long-term follow-up (P<0.001). The median BNP (brain natriuretic peptide) level at baseline was 1702 pg/mL (565-3748) and decreased to 188 pg/mL (26-348) over long-term follow-up (P=0.022). The mean wear time was 79.7±52.1 days and 21.0±4.9 hours per day. Arrhythmic event rates documented by the WCD were 9.7% for nonsustained ventricular tachycardia, 6.5% for sustained ventricular tachycardia, and 0% for ventricular fibrillation. Subsequently, 2.4% of patients experienced an appropriate WCD shock. The rate of inappropriate WCD shocks was 0.8%. All 3 patients with appropriate WCD shock had experienced ventricular tachycardia/ventricular fibrillation before WCD prescription, with only 1 patient showing a left ventricular ejection fraction <35%. Conclusions Patients with myocarditis and risk for occurrence of ventricular tachyarrhythmia may benefit from WCD use. Prior ventricular arrhythmia might appear as a better risk predictor than a reduced left ventricular ejection fraction <35% in this population.

Keywords: myocarditis; sudden cardiac death; ventricular tachycardia; wearable cardioverter‐defibrillator.

Figure 1. WCD indication.

Distribution of individual indications for use of the WCD. CIED indicates cardiac implantable electronic device; ICM, ischemic cardiomyopathy; NICM, nonischemic cardiomyopathy; and WCD, wearable cardioverter‐defibrillator.

Figure 2. Changes in LVEF and BNP.

A, Box‐whisker plot of LVEF at baseline (n=124), short‐ (n=105) and long‐term (n=67) follow‐up. B, Box‐whisker plot of BNP levels at baseline (n=58), short‐ (n=35), and long‐term (n=15) follow‐up. Boxes represent median and 25th–75th percentiles. Whiskers show minimum and maximum values. For statistical comparison a linear mixed effect model was used. A 2‐sided P value <0.05 was considered statistically significant. *P<0.05; **P<0.01; ***P<0.001. BNP indicates brain natriuretic peptide; LVEF, left ventricular ejection fraction; and n.s., not significant.