Morphological features in myocardial bridging

Abstract

Myocardial bridging is a common coronary anomaly characterized by the presence of a muscle bridge above an epicardial artery. Although its involvement in the development of severe cardiovascular pathologies is disputed there are many proofs that it may possibly be associated, in particular circumstances, with sudden cardiac death, the development of malignant arrhythmias, atherosclerosis, myocardial infarction, hibernation or stunning, etc. The development of cardiovascular complications is mainly dependent upon the presence of a significant hemodynamic obstruction. In order for a myocardial bridging to determine such an obstruction it must present some specific morphological characteristics which we will present in this article.

Myocardial Bridging: A Meta‐Analysis of Prevalence

“…Various studies suggested that, to have hemodynamic significance, a MB has to have some particular morphological characteristics (especially length and thickness) . Our study showed that a “typical” myocardial bridge has around 19 mm in length and 2.5 mm in thickness, values that can be considered hemodynamically significant .…”

Myocardial bridge and coronary arteries: morphological study and clinical significance

“…Marked reduction of the intimal thickness and changes in the endothelial cell morphology of the intima were observed in the tunnelled segment of the coronary branch. These changes might be due to the exposure of intima to a high shear stress [10]. Histologically, the intima of the bridged segment was formed only of contractile--type smooth muscle cells and an abundance of interstitial spiralled collagen, with the absence of the synthetic-type of smooth muscle cells that proliferate and produce the collagen and elastic fibres in the intima as atherosclerosis progresses [2].…”

“…Depending on the course of AIA and the direction of the overlying myocardial fibres, MB were classified into superficial and deep [10]. The authors added that in superficial MB the AIA passed within the interventricular sulcus and was crossed by the myocardial fibres perpendicular or in acute angle, while in deep form the AIA deviated towards the right ventricle.…”

“…Moreover, a third type of MB was described into which the tunnelled artery was covered partially by myocardial fibres and partly by fatty, fibrous, or nervous tissue [5]. In addition, 4 types of MB were described: superficial, deep, incomplete and subendocardial [10,18].…”

A study to find out the incidence of myocardial bridges in the formalin fixed hearts and its co relates

“…According to Dan Dermengiu et.al. (2010) (16) the length of typical myocardial bridge is usually within the 10-30 mm range, only rarely exceeding 40mm. A longer Myocardial Bridges seem to be associated with more significant hemodynamic effect and more sever clinical symptoms Some report attribute the clinical symptoms of myocardial bridges to their extensive length (Kramer et al,1982 (17) , Angelini et al,1983 (14) , Juilliere et al 1995 (18) ).…”