Considerations on the left papillary muscles microangioarchitecture

Abstract

The aim of the present study was to bring macroscopic and microscopic evidence on the left papillary muscles blood supply in human hearts. For the study were used human adult hearts from patients without clinically known cardiac ischemic history. Ten hearts were used for injecting China ink in the coronary arteries and other twenty hearts were dissected to evidence the characteristics of the main arteries of the left papillary muscles. Pieces - left papillary muscles - were drawn from the injected hearts and diaphanised. In all dissected hearts the left anterolateral papillary muscles were supplied by the left coronary system: anterior interventricular artery, second diagonal branch and left (obtuse) marginal artery. In 70% the left posteromedial papillary muscles were supplied by the right coronary system (posterior interventricular artery, left retroventricular artery) and in 30% by the left coronary system (circumflex artery). The left papillary muscles were supplied each by one or two main arteries that penetrated the muscles longitudinally. The ventricular wall attaching the papillary muscles was supplied by the subepicardial vessel sending the main arteries of the papillary muscles but also by neighbor subepicardial vessels distributed in that wall. The mural vessels were finer than the papillary muscles main arteries. Injected papillary muscles presented each with two systems of blood perfusion: one represented by segmental centers of arterial branching and distribution of the main arteries of the muscle and other represented by capillary extensions of the mural networks at that level. From the segmental branching centers were perfused the neighbor segments of the papillary muscles and intrasegmental anastomoses were recognized. The microvascular study of the left papillary muscles proves the usual overlapping of sources for segmental supply; this overlapping is reinforced by the high capillary density to ensure the vascularisation of the papillary muscles.