Ventricular performance was evaluated sequentially in 31 patients with uncomplicated acute transmural myocardial infarction (13 anterior and 18 inferior). Left ventricular ejection fraction, ejection rate, regional wall motion, and right ventricular ejection fraction were ascertained using first-pass radionuclide angiocardiography on four occasions during hospitalization. Inferior infarction resulted in a greater reduction in right ventricular ejection fraction than anterior infarction (mean +/- SEM; 48 +/- 2 versus 56 +/- 2%, P less than 0.01). In contrast, in anterior infarction there was greater depression of left ventricular ejection fraction than in inferior infarction (34 +/- 3 versus 50 +/- 3%, P less than 0.01). From initial to discharge studies, there was no significant change in global performance or regional wall motion in either group. These data show that the location of transmural infarction has a profound effect upon the magnitude of right and left ventricular dysfunction. In addition, ventricular systolic performance remains relatively stable during the hospital phase of uncomplicated transmural myocardial infarction.