Electrocardiogram of posterior wall infarction

The purpose of the study was to assess the frequency of infarction of the posterior wall of the left ventricle which shows a high R wave in leads V1-2 on electrocardiogram. Serial electrocardiograms of 1 452 patients with myocardial infarction were analyzed. Features of posterior wall infarction were found in 106 cases (7.3%). In 13 cases, the area of infarction was limited to the posterior wall; in 12 cases, concomitant features of lateral wall infarction were found; in 38 cases, the changes involved the inferior wall as well, and in 43 cases, the inferior and lateral walls were involved concomitantly. A high R wave in V1-2 was observed already in the first ECG obtained on the day of the onset of the disease in 32 out of 106 cases, while in 74 cases it appeared only in the subsequent days. High voltage of R wave was found in V1 exclusively in 20 cases, in V2 exclusively in 36 cases, and simultaneously in V1 and V2 in 50 cases. The analysis suggests that posterior wall infarction is fairly frequent (7.3%) but occurs in only 1% of cases as an isolated process. Knowledge of the features of posterior wall infarction is of practical importance; simultaneous detection of features of infarction of the posterior and the inferior or lateral walls is proof of a widespread myocardial necrosis and may be of prognostic significance.