The anatomy of the septal perforating arteries in normal and congenitally malformed hearts

Background: Many cardiac operations involve incisions and sutures on or nea r the ventricular septum. These jeopardize the septal perforating arteries. Our aim was to provide guidelines for the surgeon to predict the site of t hese vessels. Methods and results: We dissected 50 hearts. In 16 of these we also conduct ed histologic examination of the area of the septum containing the atrioven tricular node, the penetrating bundle (of His), and the branching atriovent ricular bundle to elucidate the source of the vascular supply to these stru ctures. The major perforating septal arteries arise from the superior inter ventricular artery or, in hearts with a rudimentary right ventricle, from t he superior delimiting artery. The first is usually the largest. The locati on of this artery can be predicted relative to the position of the medial p apillary muscle. In abnormal hearts, holes within the ventricular septum in the presence of a well-developed muscular outlet septum were found to devi ate the path of the septal perforating arteries in a predictable manner. Th e triangular area bordered by the margin of the ventricular septal defect, the muscular outlet septum, and the medial papillary muscle is free of majo r perforating arteries. The histologic studies showed that the conduction t issues at the base of the ventricles tend to receive their blood supply fro m arteries arising from the inferior interventricular artery, except in dou ble-inlet left ventricle, in which the arterial supply is from the right-si ded delimiting artery. Conclusion: The location of the first superior septal perforating artery is predictable in many cases. Its course leaves a triangular area on the musc ular ventricular septum that is free of major arteries.