Noncompaction Cardiomyopathy is Associated With Mechanical Dyssynchrony: A Potential Underlying Mechanism for Favorable Response to Cardiac Resynchronization Therapy

BackgroundThe aim of this study was to assess the presence of evidence of ventricular mechanical dyssynchrony in patients with isolated left ventricular noncompaction cardiomyopathy (IVNC) and the potential usefulness of cardiac resynchronization therapy (CRT) in those patients.Methods and ResultsWe studied 25 patients consecutively diagnosed with IVNC and a control group of 50 patients with dilated cardiomyopathy of different etiologies. Mechanical dyssynchrony was assessed by echocardiography by the presence of a septal flash, the time from peak septal to posterior wall displacement, and the time from septal to lateral wall peak systolic velocity. Among the patients with IVNC, 9 received CRT and were followed at 12 months. Overall, dyssynchrony parameters were significantly more frequent in IVNC, regardless of QRS duration. All 9 IVNC patients treated with CRT showed a septal flash, and a favorable response was observed in 8/9 patients (89%) regardless of QRS width.ConclusionsThe presence of mechanical dyssynchrony, amenable to correction with CRT, is common in patients with IVNC, independently from QRS width. This might be related to altered electrical endocardial activation associated with abnormal myocardium and could be the justification for the high response rate to CRT observed in these patients.