Left and Right Ventricular Function at Rest and Exercise in Patients on Maintenance Hemodialysis as Assessed with Radionuclide Ventriculography - Comparison with Normal Volunteers

Aim: To investigate left and right ventricular function at rest and during exercise in chronic hemodialysis patients. Patients and Methods: Forty patients having regular hemodialysis (mean age 38 ± 11 years, mean duration of dialysis 5.3 ± 3 years) were examined by means of maximum exercise testing and radionuclide equilibrium ventriculography after in vivo Tc-99m labeling of red blood cells. Obtained parameters were compared to 37 age-matched healthy volunteers. Results: Increase in heart rate during exercise was lower in patients (from 73 ± 11 to 113 ± 15 vs. 72 ± 8 to 135 ± 14 beats/min, p<0.01). At peak stress patients achieved a lower workload (76.4 ± 18.0 vs. 114.2 ± 15.2 W, p<0.01)) and lower exercise duration (8.7 ± 2.1 vs. 14.7 ± 1.2 min, p<0.01), and their mean blood pressure were significantly higher than in controls (121 ± 13 vs. 89 ± 7 mm Hg, and 143 ± 11 vs. 122 ± 9 mm Hg, respectively, p<0.01). Left ventricle end-diastolic (EDV), end-systolic volumes (ESV) and cardiac output (CO) at rest were significantly higher in patients (111 ± 33 vs. 71 ± 11 ml/m2 ; 45 ± 19 vs. 35 ± 9 ml/m2 ; 4.7 ± 1.7 vs. 2.6 ± 0.6 l/min/m2, respectively, p<0.001), as well during exercise (102 ± 27 vs. 69 ± 15 ml/m2 ; 34 ± 16 vs. 27 ± 10 ml/m2 ; 7.5 ± 2.2 vs. 5.4 ± 1.4 l/min/m2, respectively, p<0.001). Left ventricular ejection fraction (EF) at rest was significantly higher in patients, 59 ± 10 vs. 53 ± 8%, p<0.05. At stress LVEF did not differ significantly, but % rise in EF during exercise was significantly lower in patients. Right ventricle EDV, ESV and CO were elevated in patients at rest (124 ± 43 vs. 69 ± 19 ml/m2 ; 38 ± 24 vs. 32 ± 15 ml/m2 ; 5.1 ± 2.5 vs. 2.1 ± 1.0 l/min/m2, respectively, p<0.002), as well as in stress (112 ± 36 vs. 61 ± 23 ml/m2 ; 33 ± 21 vs. 25 ± 13 ml/m2 ; 8.1 ± 2.8 vs. 6.4 ± 1.9 l/min/m2, respectively, p<0.002). RVEF at rest was significantly higher in patients, 56 ± 10% vs. 49 ± 10%, p<0.05, but at stress did not differ significantly. Conclusion: Patients on chronic hemodialysis have significant enlargement of left and right ventricular volumes and elevated cardiac output associated with impaired maximal exercise performance, despite of preserved systolic left and right ventricular function during exercise.