Long-term myocardial effects of recombinant human erythropoietin (rhEPO) therapy were investigated in nine hemodialysis (HD) patients greater than 60 years of age. Echocardiographic studies were performed before the administration of rhEPO with a hematocrit of 20.8% +/- 1.9% and repeated after 6 (period I) and 24 months (period II) of treatment, when the hematocrit was increased to 34.1% +/- 2.3% and 32.3% +/- 2.8%, respectively. Left ventricular diameters were not significantly changed by rhEPO, although they tended to decrease at the end of the study (30.6 +/- 5.3 v 27.7 +/- 3.6 mm systole, and 50.3 +/- 3 v 46.5 +/- 3.7 mm diastole). Thickness of the interventricular septum and left ventricular posterior wall remained unaltered, although there was a downward trend (14.5 +/- 5.2 to 12.8 +/- 2.8 mm and 11.7 +/- 1.9 to 10.6 +/- 1.4 mm, respectively). Left ventricular mass index (LVM) progressively decreased from 181.5 +/- 61 to 153.8 +/- 38.3 (period I) and 135.7 +/- 45.6 g/m2 (period II, P less than 0.05). Stroke volume remained unaltered in period I, but it decreased from 93.7 +/- 10 to 65.2 +/- 12.8 mL (P less than 0.001) in period II, resulting in a decrease of cardiac index (CI) from 3.93 +/- 0.86 to 2.54 +/- 0.68 L/min/m2 (P less than 0.001) at the end of the study. Heart rate did not change during the study period. Blood pressure was kept constant, although antihypertensive therapy needed to be adjusted to prevent occurrence or aggravation of hypertension in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)