Myocardial bridging, a frequent component of the hypertrophic cardiomyopathy phenotype, lacks systematic association with sudden cardiac death.

AIMS: The clinical significance attributable to myocardial bridging of left anterior descending coronary artery in hypertrophic cardiomyopathy (HCM) remains controversial. METHODS AND
RESULTS: Prevalence and depth of coronary artery bridges (CBs) were assessed in 255 hearts, including 115 with HCM (median age 29, range 5-90; 75% male), and 140 controls. Coronary artery bridges were more common in HCM (47/115; 41%) than in patients who died of a variety of non-HCM-related causes (21/100; 21%; P = 0.002), or in patients with congenital aortic stenosis and left ventricular (LV) hypertrophy (5/40; 12%; P = 0.001). Among the HCM hearts, CBs were present in 33 of 77 patients (43%) with sudden death, in 10 of 27 (37%) with heart failure death (or heart transplantation), and in 4 of 11 (36%) with other modes of death (P = 0.826). Deeply embedded CBs (> or =2 mm) occurred with similar frequency in HCM patients with sudden (21 of 77; 27%) or heart failure death (5 of 27; 13%; P = 0.191). In sudden death patients, the presence of CB was unrelated to gender (33% in women and 45% in men, P = 0.406) and age (41% <18 years vs. 44% > or =18 years; P = 0.827).
CONCLUSION: In this morphological analysis of more than 250 hearts, CBs are a frequent component of phenotypically expressed HCM, and more common than in other disorders with or without LV hypertrophy. Although no systematic association with HCM-related sudden death is evident, our findings do not exclude the possibility that CB could contribute to increased risk in some individual patients, potentially impacting management decision-making on a case-by-case basis.