Isolated right ventricular infarction resulting from thrombotic occlusion of a hypoplastic right coronary artery.

Three cases of isolated right ventricular infarction resulting from thrombotic occlusion of a hypoplastic right coronary artery were found in 4,000 consecutive autopsies performed at Tokyo Metropolitan Geriatric Hospital. The incidence of isolated right ventricular infarction was 0.08%. The clinical profile of the first case was characterized by shock, pulmonary congestion, pleural effusion, decreased V1R and V2R on ECG, a small elevation of CPK and transaminase, elevation of fibrin degenerative products and decreased platelet count. The patient responded to volume expansion, heparin and catecholamines. One year later she died from cerebral bleeding. In the second case, mild aortic regurgitation and atrial fibrillation were present. He died suddenly during an episode of pneumonia. In the third case, there was chronic obstructive lung disease, atrial fibrillation and lung cancer. He died of respiratory failure. On autopsy, the coronary arteries revealed a marked left dominant and right hypoplastic pattern in all cases. The right coronary artery perfused only the free wall of the right ventricle. Complete occlusion of the hypoplastic right coronary artery resulted in isolated right ventricular infarction. In addition, chronic pulmonary disease and arrhythmia may be contributory.