Effects of exercise training on noninvasive cardiac measures in patients undergoing long-term hemodialysis: a randomized controlled trial.
BACKGROUND
Noninvasive screening studies may identify hemodialysis (HD) patients at increased risk of sudden cardiac death. Interventions that improve the findings of such screening studies may reduce sudden cardiac death.


METHODS
Randomized and controlled clinical trial.


METHODS
59 HD patients were randomly assigned to an exercise training group (group A; 30 patients) or control group (group B; 29 patients).


METHODS
Group A participated in a 10-month supervised exercise training program during the HD sessions (3 times weekly).


RESULTS
Each risk factor separately and the composite risk score. Patients were considered high risk according to the criteria (aerobic capacity: peak oxygen consumption [Vo(2)peak] < or = 14 mL/kg/min, left ventricular ejection fraction < or = 30%, SD of normal RR intervals [SDNN] < or = 70 milliseconds, positive T-wave alternans, or positive late potentials). Statistical analysis included a 2-group comparison of change scores and analysis of covariance adjusting for baseline.


METHODS
At entry and end of the study, Vo(2)peak and left ventricular ejection fraction were estimated, heart rate variability was calculated (measurement of SDNN, mean RR intervals), and the ratio between low- (LF) to high-frequency (HF) components (LF/HF) and late potentials and T-wave alternans were detected.


RESULTS
Baseline measurements were similar between the 2 groups. At follow-up, 9 patients from group A and 20 from group B (P = 0.003) were considered high risk. The change in number of risk markers over time was significantly different between groups (-0.5 +/- 0.7 in group A versus 0.07 +/- 0.3 in group B; P < 0.001). Additionally, the change in Vo(2)peak over time was 3.5 +/- 3.2 in group A and -0.2 +/- 3.5 mL/kg/min in group B (P < 0.001), left ventricular ejection fractions were 3.4% +/- 3.9% and 0.2% +/- 7.7% (P < 0.05), SDNNs were 12.6 +/- 16.3 and -1.1 +/- 10.2 milliseconds (P < 0.001), and LF/HF ratios were 0.3 +/- 0.4 and -0.1 +/- 0.3 (P < 0.001), respectively. Change in numerical score of the signal-averaged electrocardiogram also was found to be statistically different (P < 0.05) between groups.


CONCLUSIONS
Clinical outcomes, including survival, were not assessed.


CONCLUSIONS
Exercise training improves aerobic capacity and ameliorates some indicators of risk of sudden cardiac death in HD patients.
Kouidi
Evangelia J
EJ
Laboratory of Sports Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Grekas
Dimitrios M
DM
Deligiannis
Asterios P
AP
D002320:Cardiovascular Physiological Phenomena; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000503:physiopathology* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012307:Risk Factors; D013997:Time Factors