Incidence and predictors of major arrhythmic events after myocarditis: a systematic review and meta-analysis.

aimsLong-term arrhythmic risk after myocarditis remains uncertain, and optimal management is debated. We aimed to assess the incidence and predictors of major arrhythmic events (MAEs) after myocarditis. METHODS AND

resultsWe conducted a systematic literature review and meta-analysis including 19 observational studies on myocarditis and MAEs during follow-up. Major arrhythmic events were defined as a composite of sudden cardiac death (SCD), ventricular fibrillation (VF), aborted cardiac arrest (ACA), sustained ventricular tachycardia (sVT), and appropriate implantable cardioverter defibrillator (ICD) or wearable-cardioverter defibrillator (WCD) intervention. The primary outcome was the incidence of MAEs after discharge; secondary outcomes included occurrence of each component of MAEs and the composite of all-cause mortality or heart transplantation (HTx). Three thousand nine hundred and fifty-four patients (71% male, 67% acute, 88% complicated myocarditis) were included. At presentation, 15% had high-grade atrioventricular block (AVB), 31% heart failure, 38% MAEs. At a median follow-up of 24 months (interquartile range 19-57), 28% suffered MAEs, with a median time of presentation of 12 months. The incidence of sVT, ACA/VF, appropriate ICD/WCD intervention, and SCD were 22%, 6%, 20%, and 1%, respectively. The combined rate of all-cause mortality/HTx was 11%. At meta-regression analysis, high-grade AVB, MAEs at presentation, and fulminant myocarditis were associated with higher risk of MAEs during follow-up, while male gender resulted as a protective factor.

conclusionThe incidence of MAEs after a complicated acute myocarditis can be high over time. Further prospective studies are needed to better stratify high-risk patients, identify those with an underlying arrhythmogenic cardiomyopathy, and guide antiarrhythmic strategies.