Time domain heart rate variability analysis in patients with thalassaemia major

OBJECTIVE: Cardiac complication is one of the major causes of death in patients with thalassaemia major. Heart rate variability is a non-invasive index of neuronal modulation of heart rate. In this study, autonomic functions of the heart in a preclinical stage of heart disease were evaluated in 48 thalassaemic patients with time domain heart rate variability analysis; the control group consisted of 45 healthy subjects. METHODS AND RESULTS: Mean RR time in the study and control group was 0.73 +/- 0.1, and 0.82 +/- 0.1 ms respectively (p < 0.001). In the study group; SDNN, SDNN-i, SDANN-i, RMSSD, and PNN50 were found to be 167.4 +/- 86.2 ms, 153.9 +/- 108.1 ms, 111.4 +/- 60.4 ms, 108.9 +/- 86.7 ms, and 14.5 +/- 13.4%, respectively. Time domain parameters were significantly lower in the study group than the control group (p < 0.00 1). There was a significant positive correlation between the mean RR time and SDNN, SDNN-i, SDANN-i, RMSSD, and PNN50 (for the RMSSD p < 0.05, r = 0.31; for the others p = 0.000, and r values were 0.65, 0.65, 0.38, 0.37 for the SDNN, SDNN-i, SDANN-i, and PNN50, respectively). CONCLUSION: The analysis of heart rate variability might be helpful to detect cardiac complications in the preclinical stage of the cardiac involvement.