Assessment of heart rate recovery after exercise in patients with chronic kidney disease

In patients with Chronic Kidney Disease (CKD) cardiovascular disease risk is increased and major cause of mortality in these patients is cardiovascular diseases. Heart rate recovery (HRR) index is a method used in demonstrating the cardiac autonomic dysfunction and predicting mortality in recent years and there has been many studies about this method. In this study, we aimed to show the presence of cardiac autonomic dysfunction in patients with CKD with HRR index. 120 patients with stage 1-4 CKD who admitted to Celal Bayar University Hafsa Sultan Hospital Internal Medicine or Nephrology clinics were included in this study. 30 patients without any comorbidities who admitted to Celal Bayar University Hafsa Sultan Hospital were included as control group. Patients were categorized into 4 groups and each group had 30 patients. Exercise stress test was conducted with Bruce protocol in patients without any cardiac disease according to their history, physical examination, ECG and echocardiography. Heart rate recovery index in 1st, 2nd, 3rd and 5th minutes were evaluated. Average of 1st, 2nd, 3rd and 5th minute HRR in stage 3 and 4 CKD patients and average of 1st and 5th minute HRR in stage 2 CKD patients were significantly lower than control group. Comparison between all stages had shown that in every HRR phase, stage 4 had lower HRR index than stage 1. Also, there was a correlation between GFR and HRR index in 1st, 2nd, 3rd and 5th minutes. According to these data, it can be presumed that cardiac autonomic dysfunction starts in early stages of CKD and dysfunction gets more significant in advanced stages. This study also shows that HRR index can be used as a cardiac autonomic dysfunction indicator in CKD patients. However, further studies are required about using this method in routine evaluation. Our study will contribute to further studies and literature about this subject.