Risk factors of adverse cardiovascular events in patients with isolated non-compaction cardiomyopathy
Objective. To identify the risk factors of adverse cardiovascular events in patients with isolated non-compaction cardiomyopathy (NCCM). Material and methods. There were 90 patients with isolated NCCM aged 25 - 47 years (median 34 years; 47 men and 43 women) and symptoms of chronic heart failure (CHF) NYHA class I-II. In addition to conventional examination, all patients underwent contrast-enhanced cardiac magnetic resonance. The endpoints of the study included progression of CHF up to NYHA class III requiring in-hospital treatment, ventricular tachyarrhythmias and embolic events. Results. CHF symptoms progressed up to NYHA class III in 22 out of 90 (24.4%) patients with isolated NCCM throughout the follow-up period from 6 to 90 months (median 25 months). Univariate analysis showed that the following variables were independent risk factors of CHF progression: baseline symptoms of CHF NYHA class II (HR 2.2; 95% CI 10.3-4.8, p 0.04), reduced LV EF ≤50% according to CMR (HR 9.1; 95% CI 3.2-26.0, p<0.001), LV ESD ≥44 mm according to TTE (HR 1.1; 95% CI 1.03-1.17, p<0.003). Fourteen (15.6%) patients developed ventricular tachyarrhythmias. Their risk factors were VPB >500 beats/min on 24-hour ECG monitor (HR 5.8; 95% CI 1.9-17.6, p=0.002) and GLS ≤11% (HR 0.79; 95% CI 0.66-0.96, p<0.018). Seven (7.8%) patients developed embolic events. Their predictors were baseline symptoms of CHF class II (HR 12.7; 95% CI 1.6-10.2, p=0.017); left bundle branch block (LBBB) (HR 3.7; 95% CI 0.95-14.5, p=0.058) and myocardial fibrosis according to CMR (HR 5.8; 95% CI 2-29, p=0.032). The 2-year event-free survival rate was 56.8% (95% CI; 46.7-69.2). Conclusion. Risk factors of adverse events are baseline symptoms of CHF NYHA class II, LV EF ≤50%, LV ESD ≥44 mm, GLS ≤11%, and myocardial fibrosis according to CMR, LBBB and VPB >500 beats /min according to 24-hour ECG monitoring. These parameters can be used to identify high-risk patients.