Clinical, electrocardiographic, and ventriculographic consequences of isolated occlusion of the right coronary artery.

The effects of total occlusion of the right coronary artery, a sole lesion, were evaluated in an unselected series of 45 patients. Findings ranged from no detectable consequences to massive post-infarction left ventricular scars. Patients were divided into three groups: Group I, those without clinical or ventriculographic evidence of myocardial infarction (10 patients); Group II, those with clinical or angiographic evidence of nontransmural myocardial infarction (eight patients); Group III, those with electrocardiographic evidence of transmural myocardial infarction (27 patients). The critical compensatory importance of collateral vessels was demonstrated (1) by the difference between the presence of adequate collaterals in Groups I and II (89 percent), versus 44.5 percent in Group III (p less than 0.005), and (2) by the fact that the three patients without demonstrable collaterals showed the most extensive wall motion abnormalities. Four patients in Group I had no clinical evidence of ischemic disease, occlusion being an incidental finding. It is concluded that the natural history of total occlusion of the right coronary artery depends largely upon the function of collateral vessels.