To determine whether obvious hemodynamic advantages of continuous ambulatory peritoneal dialysis (CAPD) over intermittent hemodialysis are reflected in superior cardiac structure and function, 16 of 55 analyzed CAPD patients (CAPD duration: 28 months) were followed over 35 months with echocardiography in a prospective analysis: 26 patients had died. LV dimensions (end-diastolic: 52 +/- 7 vs. 51 +/- 8 mm; control vs. follow-up) and systolic function (ejection fraction: 63 +/- 10 vs. 59 +/- 14%) were normal. Major findings were an increase in the amount of initially observed LV hypertrophy (251 +/- 68 vs. 342 +/- 135 g; p less than 0.03) and a decrease in mean LV volume/mass ratios (0.73 +/- 0.17 vs. 0.54 +/- 0.13; p less than 0.001). Excluding patients with dilated cardiomyopathy and valve disease, the amount of progression in LV hypertrophy was related directly to mean arterial pressure and cardiac output (n = 12; p less than 0.02) despite extensive use of antihypertensive medication (1.9 +/- 1.3 vs. 1.5 +/- 1.4 drugs/patient). No correlation was found with diastolic blood pressure, hemoglobin, serum parathyroid hormone, creatinine, urea, age, or CAPD duration. We conclude that LV hypertrophy is frequent in CAPD patients and further increases during long-term CAPD treatment. Factors contributing to the progression of LV hypertrophy are hypertension and hypercirculation.