Right precordial ST and QRS changes in the diagnosis of right ventricular infarction.

Two groups of patients with anatomically proved acute myocardial infarction were compared in order to study specificity and sensitivity of the ECG criteria previously described in clinical and experimental right ventricular infarction ( RVI ). Group 1 included 21 patients with left inferior infarction and with a variable degree of right ventricular involvement; group 2 included nine patients with myocardial infarction confined to the left inferior wall. In both groups the presence of ST elevation (at least 0.05 mV) and the morphology of the QRS complex in V4R , V3R, and V1 were assessed in ECGs performed at the time of admission. Also, in order to evaluate the morphology of the ST segment and QRS complex in right precordial leads in normal subjects, an ECG with 12 standard and four right precordial leads ( V6R to V3R) was performed in 82 subjects (group 3) without clinical and ECG evidence of heart disease. Our data reveal that in normal subjects an rS pattern is always present in V3R and frequently (91%) in V4R . On the contrary, the presence of QS or QR complexes in both V4R and V3R are specific markers of right ventricular necrosis (specificity 100%; sensitivity 78%). The presence of injury and necrosis waves in V4R or V4R to V3R during inferior infarction is a useful diagnostic criterion in that it insures a highly specific diagnosis of acute RVI in the great majority (76 and 71%, respectively) of the cases with autopsy evidence of right ventricular involvement.