[Right ventricular infarct and atrioventricular blocks]

Right ventricular infarction in inferior left ventricular infarction is very common. We have examined, by means of equilibrium gated radionuclide angiography, the relationship existing between right ventricular infarction and atrioventricular block. Seventy-two patients with inferior wall myocardial infarction were studied. Thirty-nine of them had ventriculographic evidence of right ventricular infarction. Fifteen of them (38%) had a-v block in the acute phase. Only 3 patients without right ventricular involvement (9%) had a-v block. The occurrence of a-v block is usually explained by the fact that the blood supply to the a-v node depends on the right coronary artery. In the patients with right ventricular involvement, the incidence of a-v block is high just because occlusion of the right coronary artery is proximal to the branch to the a-v node. However, the presence of collateral blood supply to the a-v node makes the occurrence of a-v node not so high as expected.