Abstract 14996: Effectiveness of Cardiac Resynchronization Therapy in Patients with End-Stage Phase of Hypertrophic Cardiomyopathy: Comparison with Idiopathic Dilated Cardiomyopathy
Background: Evolution into dilated-hypokinetic phase of hypertrophic cardiomyopathy (D-HCM) represents an ominous change. Generally, patients with D-HCM were thought to be refractory to intensive medical therapy. Cardiac resynchronization therapy (CRT) is effective in heart failure patients. However effectiveness of CRT in D-HCM patients remains unclear.
Methods: Among our cohort of 170 CRT patients, we identified consecutive 22 D-HCM patients (age 55±14 years, LVEF 27±10%) and 71 patients with idiopathic dilated cardiomyopathy (DCM) (age 56±16 years, LVEF 23±10%). We compared baseline characteristics, response to CRT and subsequent cardiac events between the two groups during a mean follow-up period of 896±511 days after CRT implantation.
Results: The baseline characteristics of D-HCM patients and DCM patients were similar, except for distribution of intra-ventricular conduction delay on the electrocardiogram (D-HCM: 7/22 (32%) vs. DCM: 9/71 (13%), p=0.04). Both groups were improved symptomatically after CRT implantation. However the magnitude of LV reverse remodeling and the proportion of responders (>10% increase in LVEF or >15% reduction of LV end-systolic volume after CRT) were significantly lower than in DCM patients (D-HCM: 8/22 (36%) vs. DCM: 44/71 (62%), p=0.04). Based on the Kaplan-Meier analysis, the extent of CRT benefit associated with all-cause mortality and heart failure hospitalization was similar in the two groups within around two years, however D-HCM patients continuously progressed their morbidity and mortality compared with DCM patients in the long-term period (p=0.30, Figure). No significant difference was observed in terms of subsequent lethal ventricular arrhythmia after CRT.
Conclusion: CRT was less effective for D-HCM patients associated with LV reverse remodeling compared with DCM patients. D-HCM had been progressive and the efficacy of CRT for improving their prognosis was limited especially in the long-term period.
- © 2011 by American Heart Association, Inc.