Comparison of Long-Term Outcome between Apical and Asymmetric Septal Hypertrophic Cardiomyopathy.

OBJECTIVES

As reported, diagnostic age, gender and presence of outflow tract obstruction have an impact on prognosis in patients with hypertrophic cardiomyopathy. The aim of this study was to compare the long-term outcome between apical hypertrophic cardiomyopathy (ApHCM) and asymmetric septal hypertrophic cardiomyopathy (ASHCM) after the exclusion of these factors.

METHODS

A total of 540 patients (270 with ApHCM and 270 with ASHCM) identified in a consecutive single-center cohort were retrospectively studied. The two groups were matched by diagnostic age, gender and the presence of outflow tract obstruction. Clinical characteristics and long-term outcomes were compared.

RESULTS

The mean follow-up duration in ASHCM and ApHCM were 6.6 ± 5.5 and 7.6 ± 4.1 years, respectively. During follow-up, 16 patients experienced cardiovascular death in the ASHCM group, while 2 patients experienced cardiovascular death in the ApHCM group (6.3 vs. 0.7%, p < 0.01). Cardiovascular morbidity in the ASHCM and ApHCM groups were 39.9 and 18.5% (p < 0.01). In the multivariate Cox regression analysis late gadolinium enhancement (LGE; HR 4.81, 95% CI 1.28-78.0, p = 0.03) and unexplained syncope (HR 9.68, 95% CI 1.9-17.2, p < 0.01) were independent predictors for cardiovascular mortality. Unexplained syncope was independently associated with a higher risk for sudden cardiac death (HR 4.3, 95% CI 1.2-15.3, p = 0.02).

CONCLUSIONS

After eliminating the interference of diagnostic age, gender and outflow tract obstruction, ASHCM represented a worse prognosis with a higher incidence of cardiovascular mortality and morbidity than ApHCM. LGE was a strong predictor for cardiovascular death.