Long-term comparison of apical versus asymmetric hypertrophic cardiomyopathy

Although apical hypertrophic cardiomyopathy (HCM) has been considered to be more benign than asymmetric HCM, few studies have directly compared their clinical features. We compared the electrocardiographic data and long-term outcomes between patients with apical HCM versus asymmetric HCM. This retrospective study enrolled 796 patients (243 apical HCM and 553 asymmetric HCM). We assessed long-term all-cause and cardiac mortalities using an inverse probability of treatment weighted (IPTW) method and propensity score matched (PSM) analysis. In patients with asymmetric HCM, QT prolongation, QRS widening, PR prolongation, and pathologic Q wave were signifcantly more frequent. The incidences of early repolarization were similar (11% in apical and 12% in asymmetric HCM, P = 0.19). The median follow-up duration was 6.5 years. There was a borderline signifcant difference in overall survival rates between the apical and asymmetric HCM groups (73% versus 69%, log rank P = 0.38, IPTW: P = 0.05, PSM: P = 0.05). Regarding cardiac death, asymmetric HCM was more hazardous than apical HCM (89% versus 77%, log rank P = 0.04, IPTW: P = 0.03, PSM: P = 0.03). There was no electrocardiographic predictor for the long-term outcomes, although be-ta-blocker use was signifcantly associated with lower overall death (HR = 0.58, 95% CI = 0.41-0.81) and slightly lower cardiac death (HR = 0.86, 95% CI = 0.55-1.33). The overall survival rate of apical HCM was as high as that of asymmetric HCM, but the cardiac survival rate was signifcantly lower in patients with asymmetric HCM. Beta-blocker use was associated with better long-term outcomes.