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Background Despite therapeutic advancements, ventricular arrhythmias (VA) and sudden cardiac death (SCD) remain leading contributors to mortality in patients with dilated cardiomyopathy (DCM). Understanding the incidence of these events and identifying high-risk subgroups is critical for optimising risk stratification and treatment strategies. The current burden of VA and SCD in the era of modern guideline-directed medical therapy (GDMT) remains uncertain and topical. This study evaluates the incidence and predictors of major arrhythmic adverse cardiovascular events (MAACE) in a DCM cohort receiving optimal GDMT.Methods We analysed a cohort of 187 patients enrolled in the prospective Go-DCM study which started recruitment in 2018. Baseline clinical and imaging data were collected at recruitment and again annually at follow up extending up to 5 years. The primary endpoint was the first occurrence of MAACE, defined as any of sustained ventricular tachycardia (VT), ventricular fibrillation (VF), SCD, or aborted SCD. Secondary analysis observed the incidence of non-sustained ventricular tachycardia (NSVT) and its relationship with MAACE.Results The median follow-up was 2 years, mean age 50.5 ± 16.0 years, 65% of patients were male. Median LVEF was 50% [IQR 41 – 56]. β-blockers were prescribed in 88.8% of patients, ARNI in 78.1%, MRAs in 45.5% and SGLT2i in 18.4%. Over the follow up period, 13 patients (7.0%) experienced MAACE, with VT being the most prevalent (5.3%). SCD incidence was low at 0.5%. NSVT events occurred in 28.8% of patients with available Holter data (n=132). On multivariable analysis, LVEF ≤35% emerged as the only significant predictor of MAACE (HR 6.06, 95% CI 1.70–21.6; p=0.005). No significant associations were observed for LV end-diastolic volume >200 mL, myocardial fibrosis or NSVT.Conclusion In this contemporary cohort of patients with DCM, lower incidences of SCD and MAACE were observed as compared to historical studies, suggesting a decline in these events associated with the optimized use of GDMT. Further studies are underway to ascertain replicability of these results in a large independent external cohort.