To study the effect of operation for left ventricular (LV) aneurysm on right ventricular (RV) performance, we studied 50 patients before operation with right heart catheterization, RV angiography, and radionuclide ventriculography. Forty patients were followed up and underwent the same investigations 10 +/- 4 months after operation. At baseline, regional RV dysfunction was observed in 89% of the patients whereas global RV dysfunction was present in approximately a third. After operation, no changes in RV regional dysfunction or RV pressures were observed. However, a significant increase in RV end-diastolic (p less than 0.03) and end-systolic volume indices (p less than 0.02) along with a significant decrease in resting and exercise RV ejection fractions (p less than 0.05) was found. We were unable to demonstrate any significant relationship between preoperative RV dysfunction and surgical outcome. We conclude that RV dysfunction is common in patients with LV aneurysm. Current techniques of operative intervention for this type of aneurysm seem to be followed by RV dilatation and impairment in RV function.