Predominant right ventricular infarction. Clinical and electrocardiographic features.

Based on two-dimensional echocardiographic wall motion abnormalities, 82 patients with acute inferior wall myocardial infarction were divided into 3 groups: group 1. predominant right ventricular infarction-20 patients; group 2. combined right and left ventricular infarction-33 patients; and group 3. predominant left ventricular infarction-29 patients. There were no significant statistical differences between the three groups regarding age, sex, Killip class on admission and jugular venous engorgement. Group 2 patients had higher peak creatine kinase levels and a lower rate of life threatening ventricular arrhythmia than the other groups. On M-mode echo, patients in group 1 had higher RV/LV ratios and lower left ventricular systolic and diastolic dimensions than group 3 patients. On 2-D echo and radionuclear studies, group 1 patients had more right ventricular wall motion abnormalities and minimal left ventricular wall motion disturbances. The left ventricular ejection fraction was higher and the right ventricular ejection fraction lower in group 1 patients than in those groups 2 and 3. The electrocardiogram showed small Q and relatively tall R waves in II, III, AVF in group 1 patients, and deep Q with loss of R waves in patients with combined or exclusive left ventricular infarction (groups 2 and 3). We conclude that predominant right ventricular infarction, which occurs in 24% of inferior wall infarction patients cannot be characterized clinically; however, an electrocardiographic pattern was found to detect this form of infarction with a sensitivity of 80% and a specificity of 70%. Combined left and right ventricular infarction and exclusive left ventricular infarction could be detected electrocardiographically with a sensitivity of 70% and a specificity of only 30%.