Early Arrhythmic Events in Idiopathic Dilated Cardiomyopathy

Objectives The study sought to provide an insight into the prevalence, characterization and possible reliable indicators of early sudden cardiac death/malignant ventricular arrhythmias (SCD/MVAs) in a large cohort of dilated cardiomyopathy (DCM). Background DCM generally affects young individuals and is characterized by an unpredictable prognosis with a non-negligible risk of SCD/MVAs, particularly in early stages of disease. Methods From 1988 to 2014, 952 patients with DCM were consecutively included in the Heart Muscle Disease Registry of Trieste. Results Globally, 20 patients (2.1% of the overall population) experienced SCD/MVAs within the first 6 months after enrollment (primary endpoint). At baseline they showed a worse functional class (New York Heart Association functional class III to IV 42% vs. 22%, p = 0.038), a longer QRS complex duration (127 ± 41 ms vs. 108 ± 33 ms; p = 0.013) and a larger indexed left ventricular end-systolic volume (LVESVI) (82 ± 49 ml/m 2 vs. 67 ± 34 ml/m 2 ; p = 0.049), as compared to patients without early SCD/MVAs. Beta-blockers were less tolerated (59% vs. 83% in patients with no early SCD/MVAs; p = 0.008), mostly due to hemodynamic intolerance. At multivariate analysis, LVESVI (odds ratio [OR]: 1.012; 95% confidence interval [CI]: 1.000 to 1.024; p = 0.043) and QRS complex duration (OR: 1.017; 95% CI: 1.003 to 1.030; p = 0.015) were independently associated with the primary endpoint, whereas beta-blockers demonstrated a protective effect (OR: 0.169, CI: 0.048 to 0.593; p = 0.006). Conclusions Patients with DCM present a significant risk of major arrhythmic events in the first phase of the disease. Baseline LVESVI, QRS duration, and intolerance to beta-blocker therapy might be useful tools in the arrhythmic early risk assessment.