Variations in the blood supply of the left ventricular apex.

Contraction or perfusion abnormalities of the left ventricular apex are generally assumed to result from left anterior descending (LAD) artery disease since this vessel is the usual source of blood supply to this area of myocardium. Such an assumption may be erroneous since the left ventricular apex may be supplied by the LAD alone, both the LAD and posterior descending (PD) branch of the right coronary artery, or the PD alone. Blood supply of the left ventricular apex was prospectively studied angiographically in 431 adult patients. In 77.7%, the apex was totally supplied by the LAD. In 12.1%, the apex received dual blood supply from both the LAD and PD. In 10.2%, the LAD terminated well before the apex, which was totally supplied by the PD. With the latter two anatomic variations, the LAD tended to be shorter and smaller in caliber than usual, while the PD was longer and larger than usual. A short, narrow LAD therefore does not necessarily indicate coronary disease if the left ventricular apex is partially or completely supplied by the PD. Dysfunction or perfusion abnormalities of the apex do not necessarily indicate LAD disease.