Exercise and Cardiac Measures in Dialysis Patients

The identification of patients on hemodialysis (HD) at increased cardiac risk with powerful screening tests and the reduction of factors, which increase the probability of malignant arrhythmias are important for primary prevention of sudden cardiac death (SCD).

Study Design: randomized and controlled clinical trial. Setting & Participants: Fifty-nine HD patients were randomized into exercise training group (group A-30 patients) and controls (group B-29 patients).

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

Outcomes: The effects of exercise on the score of the non-invasive cardiac markers for SCD risk stratification and on the occurrence of each variable separately. Statistical analysis included a two-group comparison of change scores and an analysis of covariance adjusting for baseline.

Measurements: At entry and the end of the study, in all participants aerobic capacity (VO2peak) and left ventricular ejection fraction (LVEF) were estimated, late potentials and T-wave alternans were detected and heart rate variability was calculated. Specifically, from the 24-h Holter monitoring the standard deviation of all the normal R-R intervals (SDNN), the mean R-R intervals (mean RR), the low (LF) and high (HF) frequency components of the autoregressive power spectrum of the NN intervals and their ratio (LF/HF) were recorded.