Clinical Outcomes of Myocardial Bridging versus No Myocardial Bridging in Patients with Apical Hypertrophic Cardiomyopathy

Objective: To determine the prevalence and clinical effects of myocardial bridging (MB) in patients with apical hypertrophic cardiomyopathy (AHCM). Methods: Angiograms from 212 AHCM patients were reviewed to identify MB. The patients were classified into 2 groups: AHCM with and AHCM without MB. We reviewed patient records on cardiovascular (CV) risk factors, symptoms, CV events, and CV mortality. Results: In all, 60 patients with MB and 100 without MB were included. Rates of angina (61.7 vs. 40%; p = 0.008), mimicking non-ST-segment elevation myocardial infarction (15 vs. 3%, p = 0.013), and Canadian Cardiovascular Society class III/IV angina (18.3 vs. 4%; p = 0.003) were higher in patients with MB than in those without. Mean follow-up periods (65.5 ± 50.5 vs. 64.4 ± 43.6 months, p = 0.378) and CV mortality (3.3 vs. 1%; p = 0.652) were similar in the 2 groups. Kaplan-Meier estimates demonstrated that CV event-free survival rates were lower in patients with MB than in those without (71.7 vs. 88%; p = 0.022). MB, late gadolinium enhancement, and female sex were independent risk factors for CV events in a multivariate Cox regression analysis adjusted for other risk factors. Conclusion: More serious symptoms and a higher risk of CV events were observed in AHCM patients with MB than in those without MB. CV mortality was similar in these 2 groups.