Effect of Cardiac Resynchronization Therapy in Isolated Ventricular Noncompaction in Adults: Follow-Up of Four Cases

Background: An isolated ventricular noncompaction (IVNC) is an unclassified cardiomyopathy and, despite the increasing awareness of and interest in this disorder, the role of cardiac resynchronization therapy (CRT) remains obscure. Objective: The purpose of this study was to clarify the long‐term effect of CRT on IVNC in adult patients. Methods: Four cases of IVNC were included in this study. Before the CRT device was implanted, all four patients (54 ± 16‐year‐old, 4 males) presented with symptomatic congestive heart failure. Echocardiography revealed their systolic dysfunction and their left ventricular ejection fraction (LVEF) was 21 ± 8%. There was also mechanical dyssynchrony observed between the LV septum and free wall area. The QRS duration was “narrow” (112 and 120 ms) in two patients. One patient had been resuscitated from ventricular fibrillation (VF) and two had nonsustained ventricular tachycardia (VT). A CRT defibrillator (CRT‐D) was implanted in three patients with VT/VF and a CRT pacemaker (CRT‐P) in a patient without VT/VF. The LV lead was positioned in a lateral branch of the coronary sinus where a thickened noncompacted wall existed. Results: During the follow‐up period (28 ± 23 months), their congestive heart failure had improved in terms of the cardiothoracic ratio on the chest X‐ray, B‐type natriuretic peptide level, LV systolic dimension, and LVEF. No episodes of defibrillation shocks were observed. Conclusion: CRT may improve the prognosis and quality‐of‐life in patients with an IVNC with mechanical dyssynchrony.