To examine changes in left ventricular (LV) mass and function (diastolic and systolic) after successful renal allograft transplantation (RT), we prospectively studied 30 patients (19 men, 11 women, aged 37 +/- 13 years) by M-mode, two-dimensional and pulsed Doppler echocardiography at the time of surgery and 10 +/- 1.8 months later. At the time of transplantation all patients had been undergoing dialysis (4 peritoneal dialysis, 26 hemodialysis) for 2.5 +/- 3.2 years. A hematocrit of < or = 30% was present in 26 patients. After RT the mean hematocrit increased from 26 +/- 4 to 40 +/- 7 (p < 0.01), whereas systolic, diastolic and mean blood pressure (BP) remained unchanged. The LV mass index (LVMI) decreased from 201 +/- 56 to 171 +/- 41 g/m2, (p < 0.01); LV diastolic diameter corrected by body surface area (LVDDI) decreased from 298 +/- 38 to 279 +/- 35 (p < 0.01) and the LV end-diastolic volume index (LVEDVI) from 72 +/- 18 to 63 +/- 15 (p < 0.01). There were no changes in LV fractional shortening or LV end systolic wall stress. Peak late transmitral velocity (A wave) decreased from 77 +/- 16 to 68 +/- 12 cm/s (p < 0.01) with no changes in other Doppler-derived indexes of diastolic function. No fistula patency influence on changes in LV mass and function was found. After RT, BP decreased in 21 patients from 150 +/- 20 to 132 +/- 15 (p < 0.001; group I) and increased in 9 patients from 130 +/- 14 to 153 +/- 16 (p < 0.05, group II). Patients in group I suffered a reduction in LVMI (p < 0.001), LV end-diastolic diameter (p < 0.05), LVDDI (p < 0.001); LV end-diastolic volume (p < 0.05); LVEDVI (p < 0.01); cardiac index (p < 0.05), and peak late transmitral velocity (p < 0.01), but no changes in group-II patients were observed. We concluded that BP is a major determining factor with regard to changes in LV hypertrophy and function following RT. LV mass and volumes can be expected to decrease after RT in patients with BP reduction.