This study was planned to document the right ventricular function immediately after cardiomyoplasty. Right ventricular volumes were calculated with the use of fast response thermistor. Right ventricular end-diastolic volume was reduced from 91 +/- 8 mL/M2 to 75 +/- 7 mL/M2 (p < 0.05) and right ventricular end-systolic volumes increased from 51 +/- 5 mL/M2 to 59 +/- 4 mL/M2 24 hours after the operation. Central venous pressure was raised from 2 +/- 1 to 9 +/- 3 mm H2O. These changes were interpreted as impairment of the right ventricular diastolic function. Cardiac index raised from 1.8 +/- 0.5 L/M2 per minute to 2.7 +/- 0.3 L/m2 per minute within a period of 7 days (p < 0.05). As a result of this study, we concluded that preoperatively normal right ventricular function deteriorates after the cardiomyoplasty. In the intensive care unit volume balance must be carefully monitored to avoid creating right ventricular dysfunction.