Radionuclide angiographic exercise left ventricular performance in chronic aortic regurgitation: Relationship to resting echographic ventricular dimensions and systolic wall stress index

Forty-five patients with chronic aortic regurgitation (AR) underwent first-pass radionuclide angiocardiography (RNA) at rest and during upright bicycle exercise, as well as M-mode echocardiography at rest. Abnormal left ventricular (LV) exercise reserve, defined by the absolute change in ejection fraction (EF), was present in 16 of 45 patients (36%). Seven of ten patients with abnormal resting EF (< 50%) and three of seven symptomatic patients had normal LV exercise responses. Patients with normal LV exercise reserve by RNA had LV dimensions by echo at end diastole (5.9 ± 0.2 vs 6.5 ± 0.3 cm, p = NS) and end systole (3.9 ± 0.2 vs 4.4 ± 0.3 cm, p = NS) comparable to those in patients with abnormal LV exercise reserve. However, the mean corrected LV end-diastolic (LVED) radius/wall thickness ratio was significantly greater in AR patients with abnormal LV exercise reserve than in those with normal LV exercise reserve (395 ± 15 vs 315 ± 16, p < 0.01). These data suggest that resting echocardiographic LV dimensions as well as the corrected echo LVED radius/wall thickness ratio have a variable relationship to RNA LV exercise performance in patients with chronic AR.