Morphological characteristics of the myocardial bridges in the level of the anterior interventricular branch of a human fetal heart

Background/Aim. Myocardial bridges (MB) are narrower or wider fascicles of the atrial or ventricular muscle fibres which form a "bridge" either across the main trunks of coronary arteries or their major subepicardial branches. The aim of this research was to determine and present the exact frequency, morphological, morphometric and histological characteristics of the MB in the level of anterior interven-tricular branch (AIB) in human fetal hearts. Methods. The study was performed on 63 human fetal hearts. Images of the analyzed hearts were captured with a digital camera and afterwards morphometrically evaluated with ImageJ. Characteristic cases of the MB were dissected, sampled and further routinely processed for the subsequent histological analysis. Finally, the obtained morphometric data were statistically analyzed. Results. The presence of the MB on the AIB was proven histologically and under the magnifying glass. Myocardial bridges were found in 53.97% of the hearts. The percentage of the hearts with only one MB detected on AIB 88.24% was significantly higher than the percentage of the hearts with two MBs on the AIB (11.76%) (p < 0.001). Conclusion. We suggest that the MBs are just one anatomical variation of the fetal period as well as of adulthood.