Right ventricular infarction. The evolution of ST-segment elevation and Q wave in right chest leads.

ST-segment elevation in right chest leads V3R-V7R and Q wave in V3R was measured early (1-4 hours) and late (18-24 hours) after the onset of infarction in six patients. The patients died within 9 days of infarction, and autopsy demonstrated more than 50% necrosis of the right ventricle (inclusion criterion). Abnormal ST elevation was recorded in all patients in the early and late electrocardiograms, but mean ST elevation decreased significantly between these recordings. ST elevation greater than or equal to 1 mm was recorded in all patients in the early electrocardiogram but was present in only three (50%) in the second electrocardiogram. The number of leads exhibiting abnormal ST elevation decreased from 27 (90%) to 24 (80%) (NS), and those exhibiting ST elevation greater than or equal to 1 mm decreased from 24 (80%) to 15 (50%), (p less than 0.05). Q wave in V3R was present in both electrocardiograms in three patients. Evolution of Q wave was seen in only one patient, whereas two patients were without Q wave in both electrocardiograms. These results indicate that ST elevation in V3R-V7R may vanish within the initial 24 hours despite large right ventricular infarction. Furthermore, Q wave in V3R may evolve very early after the onset of right ventricular infarction.