Incidence, Clinical Characteristics and Prognosis of Left Bundle Branch Block Induced Cardiomyopathy in Patients with Idiopathic Dilated Cardiomyopathy after Cardiac Resynchronization Therapy

概要

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Background: Cardiac resynchronization therapy (CRT) showed complete recovery of cardiac function in some patients with idiopathic dilated cardiomyopathy (DCM). Objective: To clarify the incidence, clinical characteristics and prognosis of these patients. Methods: Consecutive 44 patients (67±10 years, 29 males) with severe heart failure diagnosed as DCM, left ventricular ejection fraction (LVEF)<35%, NYHA class III or IV and QRS interval>120 ms who underwent CRT excluding previously device implanted cases were studied. We compared clinical characteristics and long term (37±10 months) prognosis among patients with hyperresponders (LVEF>50%), responders (>5% improvement of LVEF but <LVEF 50%) and nonresponders. Results: Eight patients (18%) were hyperresponders, 27 patients (61%) were responders and Nine patients (20%) were nonresponders. In all hyperresponder patients, QRS morphology had been typical complete left bundle branch block (LBBB) before CRT and LV leads had been implanted in lateral or posterolateral veins. QRS interval after CRT was significantly shorter in hyperresponders than that in responders and nonresponders (128±15 ms vs. 143±20 ms vs. 160±36 ms). Re-hospitalization caused by heart failure was much less in hyperresponders (0%) and responders (19%) than in nonresponders (78%). Conclusion: LBBB induced cardiomyopathy might be included in DCM and hyperresponders after CRT expects the extremely good prognosis.