Changes in the circulating volume associated with haemodialysis result in modification of left ventricular loading conditions. To determine the influence of haemodialysis on Doppler indices of left ventricular filling, 12 patients (mean age 40.8 +/- 2.7 (SEM) years) with renal insufficiency but without overt heart disease were studied by Doppler-echocardiography immediately before and after haemodialysis. Haemodialysis resulted in a decrease in body weight from 68.0 +/- 3.8 kg to 65.0 +/- 3.7 kg (P < 0.01). Heart rate and blood pressure did not change significantly during haemodialysis. Left ventricular diastolic dimension (M-mode) decreased from 53.5 +/- 1.1 mm to 49.5 +/- 1.9 mm (P < 0.05), whereas the shortening fraction did not change. Haemodialysis elicited marked changes in the early diastolic rapid filling wave (E wave) recorded by pulsed Doppler at the level of the mitral annulus. Peak velocity of the early rapid filling phase (peak E) decreased significantly from 95.3 +/- 8.2 cm.s-1 to 63.0 +/- 5.7 cm.s-1 (P < 0.001) and mid-diastolic deceleration of transmitral velocity decreased from 437.3 +/- 54.2 cm.s-2 to 239.7 +/- 54.4 cm.s-2 (P < 0.01). The peak filling velocity during atrial contraction (peak A) did not change (79.7 +/- 6.3 cm.s-1 vs 74.1 +/- 4.7 cm.s-1; P = NS). The ratio peak E/peak A decreased from 1.19 +/- 0.06 to 0.85 +/- 0.04 (P < 0.01) during haemodialysis. The results provide further evidence for the pronounced preload-dependence of Doppler indices of left ventricular diastolic function.