S. D. Nalinakumari1, N. Vinay Kumar2, S. Sasi Kumar3, T. S. Gugapriya4

INTRODUCTION: A band overlying the intramural segment of coronary artery-a place where the artery goes through myocardium instead of epicardium is called myocardial bridging (MB). A wide variation of 0.5%-90.4% occurs in the incidence of MB by the cadaveric and angiographic study. More over the occurrence of atherosclerosis in coronary artery segments under myocardial bridges still remains controversial. And so, the incidence of myocardial bridges and their association to atherosclerosis formation in cadaveric hearts was done morphologically and histological in this study.

METHODS: 30 cadaveric hearts from department of Anatomy were examined. After cleaning the fat from epicardium, course of all three coronary arteries were delineated and observed for presence of MB. In the hearts that exhibited MB, the location, length of MB, its distance from the coronary ostium was measured. Sections were made proximal to MB, under MB and distal to MB in the vessels. The perimeter of the vessels were measured. The section was processed for histological study of intimal–media thickness ratio.

RESULT: 24 hearts showed MB in the left anterior interventricular artery. One showed MB in right coronary artery. Multiple MB in single artery was seen rarely. The length of the MB segment was around 4 cm on an average. Mostly the MB is seen in the mid to distal part of the artery. The intima was found to be thinned out in the section of the vessel underneath the MB.

CONCLUSION: This study concludes that Left coronary artery is the commonest to have myocardial bridges. But the occurrence of this MB in the distal part of the vessel in contrast to previous studies is an important finding to be noted. The presence of intimal thinning underlying the myocardial bridges questions the previous studies that claimed MBâ??s protection of vessels from atherosclerosis.