Objective: To compare the clinical features and long-term outcome of patients with midventricular obstructive hypertrophic cardiomyopathy (MVOHCM) and patients with apical hypertrophic cardiomyopathy (AHCM) in China.
Methods: This retrospective study analyzed clinical data of 66 patients with MVOHCM and 263 patients with AHCM from a consecutive single-center cohort consisting of 2 413 patients with HCM. The clinical features, cardiovascular mortality and morbidity were compared between the two groups.
Results: Compared with the AHCM, patients in the MVOHCM group was younger and more likely to be symptomatic over a mean follow-up of 7 years. The proportion of MVOHCM and AHCM were 2.7% (66/2 413) and 10.9% (263/2 413) (P < 0.001), respectively, in this cohort. Cardiovascular mortality of the two groups were 13.6% (9/66) and 0.8% (2/263) (P < 0.001), and cardiovascular morbidity of the two groups were 53.0% (35/66) and 14.4% (38/263) (P < 0.001).
Conclusion: MVOHCM is rarer, but the clinical manifestations and long-term outcomes are worse compared with AHCM in this patient cohort.