The surgical indications in aortic regurgitation (AR) depend on the functional performances of the left ventricle (LV) and its reactions to the chronic volume overload. The relation between patient symptomatology and the hemodynamic data in isolated chronic AR were studied by correlating parameters obtained at catheterisation and biplane left cineventriculography under basal conditions and post-extrasystolic potentialisation (PEP) with the NYHA functional classification of 51 patients with AR. Fifteen patients were in Class I, 26 in Class II, 10 in Class III and none in Class IV. The mean regurgitant fraction (0,55 +/- 0,15), cardiac index (3,1 +/- 0,7 1/min/m2) and left ventricular end diastolic pressure (LVEDP) (14 +/- 7 mmHg) were comparable in the 3 classes of patients. Three significant differences were observed between Class I and Class III: --The LV ejection fraction was significantly lower (I = 0,53 +/- 0,13; II = 0,50 +/- 0,39; III = 0,42 +/- 0,17, p less than 0,04). --The LV end systolic volume was significantly higher (I = 88 +/- 48; II = 90 +/- 31; III = 138 +/- 68 ml/m2, p less than 0,02). --The myocardial mass was significantly greater (I = 168 +/- 57; II = 204 +/- 94; III = 291 +/- 128 g/m2, p less than 0,003). Under basal conditions, this was the only parameter distinguishing asymptomatic from symptomatic AR. The increase in LV ejection fraction during PEP was similar in all 3 groups, as was the increase in LVEDP (+36 p. 100). The LV systolic pressure of the potentialised complex was the only parameter which distinguished Class I and Class III patients.