Comparison of Benefits from Cardiac Resynchronization Therapy between Patients with Ischemic Cardiomyopathy and Patients with Idiopathic Dilated Cardiomyopathy

Background: Cardiac resynchronization therapy (CRT) is an effective treatment for patients with moderate to severe heart failure. However, 20-30% of patients remain non-responders to CRT. We sought to identify which patients benefit the most from CRT in regard to the etiology of heart failure. Methods: Eighty-three consecutive patients (62 men) who had a biventricular pacemaker inserted at Tehran Heart Center between May 2004 and March 2007 were evaluated retrospectively. The inclusion criteria were comprised of New York Heart Association (NYHA) class III or IV, left ventricular ejection fraction < 35%, and QRS > 120ms. After 6 months, response was defined as being alive, no hospitalization for cardiac decompensation, and an improvement in NYHA class > 1 grade. Results: After 6 months, 60 patients out of the 83 patients were responders. Amongst the 83 patients, 48 had ischemic cardiomyopathy and 35 had non-ischemic cardiomyopathy. A cross-tabulation of response versus etiology showed no significant difference between ischemic versus non-ischemic cardiomyopathy with regard to response to CRT (P=0.322). Conclusion: According to our study, there was no difference in response to CRT between ischemic versus non-ischemic cardiomyopathy at six months’ follow-up.