Clinical Features of the Dilated Phase of Hypertrophic Cardiomyopathy in Comparison With Those of Dilated Cardiomyopathy

Background Although the dilated phase of hypertrophic cardiomyopathy (D-HCM) characterized by left ventricular (LV) systolic dysfunction and cavity dilatation has been reported to be a poor prognosis, this is now in contrast to the improved prognosis of dilated cardiomyopathy (DCM) in the era of advancements in heart failure management. There has been no investigation of the clinical features of D-HCM compared with those of DCM from the point of management of systolic dysfunction. Hypothesis The aim of this study was to investigate the clinical features of D-HCM in comparison with those of DCM in a single institute. Methods We studied 20 consecutive patients with D-HCM (global ejection fraction < 50%) and 115 consecutive patients with DCM. Results At diagnosis of D-HCM, 8 (40%) of the D-HCM patients already experienced dyspnea (New York Heart Association [NYHA] class ≥ III). Left atrial diameter was larger and prevalence of atrial fibrillation was higher in the D-HCM group, although LV size was larger and LV ejection fraction was lower in the DCM group. During the follow-up period (4.0 years), 11 (55%) of the patients with D-HCM died. The 5-year survival rate from all-cause mortality including cardiac transplantation was 45.6% in patients with D-HCM vs 81.6% in patients with DCM (log-rank P = .0001). Conclusions Patients with D-HCM were more symptomatic at diagnosis, although LV dilatation and impaired fractional shortening seemed more severe in patients with DCM. The prognosis for D-HCM patients was worse than that for patients with DCM despite similar or even more intensive treatment for heart failure. Copyright © 2010 Wiley Periodicals, Inc.