Background: Patients with chronic kidney disease (CKD) had a high risk of fatal arrhythmias. The extended corrected QT (QTc) interval is a hallmark of ventricular arrhythmias and sudden cardiac death. Studies have shown that QT interval and QTc were prolonged with the declination in renal function. Notably, QTc prolongation is significantly increased in patients undergoing hemodialysis. However, there were no results available in patients with peritoneal dialysis (PD). This study aimed to report the changes in QT interval and QTc in PD patients.
Methods: A total of 66 PD patients were enrolled. The duration of follow-up was 1 year. The demographics, and the etiology of patients were recorded. QTc of ECG and clinical biochemical indexes before dialysis and at 6 months after PD and 1year after PD were determined and analyzed. Dialysis adequacy and peritoneal transport function were assessed in each patient.
Results: (1) A total of 66 PD incident patients, including 50 males and 16 females, with an average age of 43.56±15.15 years (males: 43.74±15.53 years; females: 43.00 ± 15.92 years) were enrolled. In terms of etiology, 37 patients (56.06%) had chronic nephritis, followed by diabetic nephropathy in 11 patients (16.67%), IgA nephropathy with 8 patients (12.12%). The peritoneal transport test showed that the most of the peritoneal transport function was low average transport( 25, 37.88%), the least was high transport(2, 3.03%).
(2) During the follow-up period, all patients reached the standard of PD. Compared with baseline before dialysis, anemia, low albumin, blood pressure, blood urea nitrogen, creatinine, uric acid, potassium, calcium, phosphorus and parathyroid hormone were improved after PD at 6 months and 1year. The residual renal function was gradually decreases during the follow-up. There were no significant differences in clinical indexes between 6 months and 1 year after PD.
(3) The mean QTc of all patients were stable during 1-year follow-up period (pre-PD: 413.49±29.95ms; 6 months: 423.05±51.96ms; 1 year: 409.29±32.32ms, P>0.05). According to gender, the QTc in male patients and in female patients had the same results (P>0.05, respectively).
(4) Before PD, diastolic blood pressure (r=-0.261,P=0.039), calcium concentration (r=-0.360,P=0.004) and hemoglobin level (r=-0.432,P=0.000) were found to be the risk factors of QTc prolongation. They were negatively correlated with QTc in end-stage renal disease patients. After patients starting PD, the observed clinical indicators showed no relevance to QTc anymore.
Conclusion: Different from hemodialysis induced QTc prolongation, PD did not increase the patient's QT interval and QTc interval. This phenomenon was reported for the first time, suggesting that myocardial electrical activity might be more stable in PD patients.