Background: Myocardial bridges represent a hotly debated research topic. Myocardial bridges are considered to be a vascular heart variation due to its intermittent or enduring reducing of the arterial lumen, with a possible ischemic effect.
Methods: 154 hearts were studied, having been extracted as fresh autopsy material. Coronary arteries were injected with synthetic resin and cleaned by extracting the pericardial fat.
Results: 92 myocardial bridges were observed in 62 hearts (40.3%). Average myocardial bridge length was 19.9 mm. Myocardial bridges varied per artery from one myocardial bridge in 42 hearts (27.3%), two myocardial bridges in 11 hearts (7.2%), three myocardial bridges in 8 hearts (5.2%) and four myocardial bridges in 1 heart (0.7%). Most myocardial bridges coincided with the anterior interventricular artery in its proximal and intermediate segments in 61 cases (39.6%) and left diagonal artery in 11 cases (7.2%). Arteries emitted just before myocardial bridges (pre-bridge branch) in 50 cases (54.3%) of the sample, with an average caliber of 1.41 mm. A third coronary artery was present in 46 cases (29.8%) of total sample. A higher frequency of myocardial bridges was found in hearts with a third coronary artery.
Conclusion: It is necessary to consider the clinical importance of the variations considering the arterial distribution and associated clinical implications.