The vascular supply of the left ventricular wall: Anatomic observations, plus a hypothesis regarding acute events in coronary artery disease

Postmortem injection studies of the left ventricular wall in 58 human hearts have revealed a characteristic distribution of vessels: those which divide quickly (Class A), and those which penetrate to the subendocardial layers, forming multiple anastomosing arcades (Class B). This subendocardial plexus appears to play an important role as a collateral channel in coronary disease. These anatomic features suggest an explanation for certain features observed in patients with coronary artery disease. This concept assigns a permissive role to the large occlusive lesions of the coronary arteries. Such lesions make the potentially ischemic focus distal to the occlusion dependent on collateral flow through the subendocardial plexus, thus permitting dynamic factors that modify this collateral circulation to become critically significant.