Myocardial bridging of coronary arteries: A risk factor for myocardial fibrosis?

Myocardial bridging of a coronary artery is an anatomic anomaly in which a major epicardial coronary artery extends intramurally into the myocardium for a part of the vessel's course. The left anterior descending coronary artery (LAD) is most frequently involved. Myocardial bridging is often asymptomatic, although myocardial pathology, arrhythmias and sudden cardiac death have been reported. In this study we quantitated the degree of myocardial intersitial fibrosis in histological sections of the anterior wall of the left ventricle obtained from the hearts of 6 individuals with myocardial bridging of the LAD and compared it to age-, weight-, and sex-matched controls without bridging. We found that patients with the bridging of the LAD had 33% increased myocardial interstitial fibrosis as compared to the control group (P=0.0006). Our data suggest that myocardial bridging may be an independent risk factor for development of myocardial ischemia and interstitial fibrosis.