Importance of lead aVR on predicting adverse cardiac events in patients with noncompaction cardiomyopathy

Background Noncompaction cardiomyopathy (NCCM) is a relatively rare cardiac abnormality with high rates of mortality and morbidity. T-wave amplitudes during ventricular repolarization in lead aVR (TaVR) have been reported to be associated with the prognosis of various cardiovascular diseases. This study sought to investigate the prevalence and prognostic role of positive TaVR in patients with NCCM. Methods We evaluated consecutive 161 patients with NCCM (65.8% men, mean age 42.5 +/- 15.2 years old). Presentation electrocardiogram was assessed regarding classical parameters as well as T-wave amplitudes in lead aVR. The primary endpoint was defined as composite lethal arrhythmic events, including sudden cardiac death, ventricular fibrillation, or sustained ventricular tachycardia or appropriate implantable cardioverter-defibrillator shock. Heart failure requiring hospitalization, cardiovascular death, and all-cause mortality were also investigated as secondary endpoints. Results Patients with positive TaVR showed higher rates for arrhythmic events, hospitalization for heart failure, and death compared with patients without it. In multivariate Cox model, after adjusting for other known clinical and electrocardiographic risk factors, the positive TaVR was found to be a strong independent predictor of primary endpoint (HR: 4.8, 95% CI: 1.2-19.3; p = .025) and all-cause death (HR: 3.5, 95% CI: 1.0-12.1; p = .045). Conclusion Our findings revealed that positive TaVR is significantly and independently associated with adverse outcomes in NCCM patients. This unique ECG criterion in the often ignored lead provides incremental information beyond what is available with other traditional risk factors.