QT/corrected QT (QTc) intervals and QT/QTc dispersions in children with chronic renal failure

We aimed to examine QT/corrected QT (QTc) intervals, QT/QTc dispersions (QTD/QTcD) and also the effect of different clinical and laboratory variables on these parameters in children with chronic renal failure. Serum biochemistry, 12-lead electrocardiogram, telecardiogram, and echocardiography were performed in 50 children with chronic renal failure (23 female and 27 male; aged 12.3±3.6 years, range 5 to 20 years). None of them had symptoms related to arrhythmias. When compared with a control group (372 children, aged 7 to 18 years, mean 12.4±2.6) patients with chronic renal failure had greater QT/QTc intervals and QT/QTc dispersion values (Patient: QT=360.9±53.3; QTc=438.5±33.2; QTD=42.4±20.8; QTcD=57.5±23.8; Control: QT=325.9±24.1; QTc=398.7±19.7; QTD=29.9±10.2; QTcD=47.3±16.6; P<0.01). QT, QTc, and QTcD values were significantly greater in patients who had renal failure duration longer than 2 years. Patients who had impaired left ventricular systolic function on echocardiogram had greater QTc, QTD, and QTcD values. It was found that sex, cardiomegaly on chest X-ray, and left ventricular hypertrophy on echocardiogram were not related to these parameters. It is concluded that, impaired cardiac systolic function and longer renal failure duration are related to an increase in QT, QTc, QTD, and QTcD values and hence these variables may be risk factors for ventricular arrhythmias in uremic patients.