Using a rapid computerized thermodilution method, we examined the evolution of right ventricular performance in 23 patients with septic shock. Nine survived the episode of septic shock. The other 14 patients died of refractory circulatory shock. Significant right ventricular systolic dysfunction, defined as decreased ejection fraction (-39%) and right ventricular dilation (+38%) was observed in all patients with septic shock. However, in the survivors, increased right ventricular preload may prevent hemodynamic evidence of right ventricular pump failure by utilizing the Frank-Starling mechanism to maintain stroke volume. Conversely, in the nonsurvivors, right ventricular dysfunction was more prononced two days after the onset of septic shock, leading to a fall in stroke. In the last patients, a decrease in contractility appears to be the major factor accounting for decreased right ventricular performance, as evidenced by the marked increase in end-systolic volume (+27%) without significant change in pulmonary artery pressure, during the later stage of septic shock. The observed right ventricular pump failure then appears associated with an alteration in diastolic mechanical properties of this ventricle, as suggested by a leftward displacement of the individual pressure-volume curves.