A Morphological Study of Myocardial Bridges in the Fetal Heart.

Myocardial bridges (MB) are congenital anomalies of hearts observed as muscle fibers covering epicardial branches of the coronary artery. The left anterior descending artery (LAD) was found to be commonly showing myocardial bridges (MBs). Clinically, MBs were claimed to cause varied symptomatology. The data on the morphology and prevalence of MBs in fetuses was limited, despite the commonly accepted congenital origin. Fetal hearts obtained from 37 fetuses from the donation program were used. The hearts were dissected out from the thorax by standard dissection procedure. The pericardium and epicardium were dissected. The coronary arteries were delineated, and MBs were observed and noted. The coronary artery segment having MBs, its distance from the ostium as well as the direction and length of the MBs were studied. The MBs were observed in 20 out of 37 fetal hearts studied over the left anterior descending, right coronary, posterior interventricular and circumflex arteries. The mid or distal part of the coronary arteries frequently exhibited MBs. The mean length of the MB was 4.2 mm, with MBs being situated about 1.5 cm away from the coronary ostium. The oblique pattern of MB was more frequently noted. The morphology and prevalence of fetal MBs showed common occurrence in the LAD artery, with a predominant oblique morphological pattern.