To evaluate the ability of two-dimensional echocardiographic indexes to determine the hemodynamic significance of the right ventricular infarction, 24 patients with electrocardiographic evidence of right ventricular infarction were studied. Hemodynamic significance was defined as a jugular venous pressure greater than 17 cm H2O or a right atrial pressure greater than 13 mm Hg. Patients with hemodynamically significant right ventricular infarctions (group I, n = 9) had a 56% incidence of hypotension (blood pressure less than 90 mm Hg) with a mean systolic blood pressure of 93 +/- 23 mm Hg, whereas patients with nonhemodynamically significant right ventricular infarctions (group II, n = 15) had no hypotension and a mean systolic blood pressure of 121 +/- 18 mm Hg (p less than 0.01). The ratio of right atrial to pulmonary capillary wedge pressure was 1.1 +/- 0.6 in group I and 0.6 +/- 0.2 in group II (p less than 0.05). Echocardiography demonstrated right ventricular free wall motion abnormalities in seven patients in group I and in 10 patients in group II. The descent of the right ventricular base was 0.7 +/- 0.2 cm in group I, 1.3 +/- 0.4 cm in group II, and 2.0 +/- 0.2 cm in a group of 20 normal control patients (p less than 0.001 for all comparisons). The respiratory caval index (percentage of collapse of the inferior vena cava with inspiration) was 22% +/- 11% in group I, 45% +/- 15% in group II, and 64% +/- 17% in the control subjects (p less than 0.05 for all comparisons).(ABSTRACT TRUNCATED AT 250 WORDS)