Objective: To describe the clinical characteristics with long-term prognosis in patients with mid-ventricular obstructive hypertrophic cardiomyopathy (MVOHCM).
Methods: A total of 66 MVOHCM patients treated in our hospital were retrospectively studied for their morbidity, clinical characteristics and mortality. The cumulative survival rate was calculated by Kaplan-Meier method; the risk factors for cardiac death and cardiovascular events were analyzed by uni- and multivariate Cox proportional hazard model.
Results: There were 66 (2.74%) patients suffering from MVOHCM among 2413 patients of hypertrophic cardiomyopathy and the average diagnostic age was (40.16 ± 14.64) years. With (7.30 ± 6.25) years of follow-up study, the cardiovascular mortality was 13.6% and unexplained syncope (HR=13.37, 95% CI: 1.65-114.46, P=0.015) was the independent predictor for cardiovascular death. There were 45.45% (30/66) patients experienced at least 1 time of cardiovascular event and the most frequent one was non-sustained ventricular tachycardia (NSVT); 19.70% (13/66) of patients combined with apical aneurysms, and they were more inclined to experience NSVT.
Conclusion: MVOHCM patients usually have unfavorable prognosis with the higher incidence of cardiovascular events, some patients may develop apical aneurysm. The early diagnosis of MVOHCM is important for appropriate treatment.

OBJECTIVETo 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.

METHODSThis 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.

RESULTSCompared 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).

CONCLUSIONMVOHCM is rarer, but the clinical manifestations and long-term outcomes are worse compared with AHCM in this patient cohort.

Cardiomyopathy, Hypertrophic ; Humans ; Retrospective Studies