Does renal transplantation actually improve heart rate variability?

Objectives: The End-Stage Renal Disease (ESRD) patients have high mortality rates despite the modern pharmacological and renal replacement therapies. Heart Rate Variability (HRV) is one of the markers of autonomic nervous system activity. The negative prognostic effect of the deteriorated HRV was clearly shown in several diseases. In our study, we have examined the effect of renal transplantation on HRV in ESRD patients. Methods: 50 consecutive (12 females, 38 males) patients who underwent renal transplantation enrolled in the study. 24-hour Holter Electrocardiography (ECG) monitoring was done in all patients before and at the end of the third month of the transplantation in order to evaluate HRV. Time-domain HRV analyses were performed by using the recordings of the Holter ECG monitoring. Furthermore, transthoracic echocardiography was done before and early period after the transplantation, and the left ventricular mass index was compared. Results: The average age was 42.38 ± 13.45. Hypertension was the most frequent comorbid disease (74%). The decrease in all HRV parameters (mNN, SDNN, SDANN, RMSSD, SDNN index) was observed on evaluation at the end of the third month of the transplantation compared with the pre-transplant values, but this difference was not important. In addition, it has been observed that a statistically significant decrease in the left ventricular mass index on evaluation at the end of the third month of the transplantation when compared to the pre-transplantation period (137.99 ± 47.11 vs. 126.85 ± 45.29, P=0.01). Conclusions: The downward trends of HRV values can be one of the markers of increased cardiovascular risk in early post-transplantation period in patients with ESRD.