Correlation between QT Variability Index and Glomerular Filtration Rate in Predialysis Chronic Kidney Disease

Chronic kidney disease (CKD) patients are at increased risk for ventricular arrhythmia and sudden cardiac death (SCD). The rate of SCD in CKD patients increased as glomerular filtration rate decreased. Sudden cardiac death is generally mediated by ventricular arrhythmias associated with instability of myocardial repolarization. QT variability index (QTVI) as an index of myocardial repolarization instability is a strong predictor for fatal ventricular arrhythmias and SCD. The aim of this study was to evaluate correlation between QTVI and GFR(< 60 mL/minute) in predialysis CKD patients. This study was done in Kidney and Hypertension Clinic of Dr. Hasan Sadikin Hospital Bandung, from October to December 2011. A total of 51 subjects were included in this study and had their resting electrocardiography (ECG) recorded and QTVI calculated, 94% had hypertension or received anti hypertension, while only 37% fulfilled the ECG criteria for left ventricular hypertrophy. We determined the correlation between QTVI and GFR using Spearman's rank, with mean QTVI 0.16 (SD 0.24), we had strong and significant correlation between QTVI and GFR (r=-0.816, p <0.001) and moderate correlation between QTVI and estimated glomerular filtration rate (r=-0.460, p<0.001). In conclusions, there is a strong correlation between QTVI and GFR in predialysis CKD patients, the lower GFR the higher QTVI value.