Dynamic QT interval analysis in uraemic patients receiving chronic haemodialysis
- 1 October 2003
- journal article
- Published by Ovid Technologies (Wolters Kluwer Health) in Journal of Hypertension
- Vol. 21 (10), 1921-1926
- https://doi.org/10.1097/00004872-200310000-00020
Abstract
Objective To analyse the duration of the QT interval and its relationship with heart rate changes in patients with uraemia, before and during haemodialysis. Methods QT and RR intervals were measured automatically using a dedicated algorithm with 24-h Holter recordings in 29 patients (15 women) receiving chronic haemodialysis. QT corrected for heart rate (QTc) and the slope of QT/RR linear regression were calculated. Arterial blood pressure (ABP) was measured before and during haemodialysis. Plasma concentrations of K+, Mg2+ and Ca2+ were assessed before and after haemodialysis. Results ABP decreased significantly from baseline (102.7 ± 11.0 mmHg) during the first (100.6 ± 8.8 mmHg, P< 0.05), second (95.6 ± 10.6 mmHg, P< 0.05), and third (94.9 ± 10.3 mmHg, P< 0.05) hours of haemodialysis. QTc was longer during haemodialysis than during a 4-h period of no dialysis (447 ± 28 ms compared with 429 ± 22 ms, P< 0.001), and increased progressively during haemodialysis, with the greatest value during the last hour of haemodialysis (454 ± 32 ms compared with 426 ± 22 ms, P< 0.001). QT/RR slopes and correlation coefficients were lower during haemodialysis than during the period of no dialysis (0.13 ± 0.08 compared with 0.20 ± 0.07, P< 0.001 and 0.48 ± 0.30 compared with 0.81 ± 0.20, respectively; P< 0.001), suggesting a reduced ability to adapt the QT interval in response to changes in heart rate. The effects of haemodialysis on QT interval and the QT/RR relationship were greater in women than in men. QTc variations during dialysis were not correlated with changes in ABP, but were inversely related to changes in Ca2+ concentration (r2 = 0.35; P = 0.001). Conclusions In patients with uraemia, the haemodialysis session induces a progressive increase in QT interval and modifies its relationship with heart rate. These effects may predispose some individuals to ventricular arrhythmias at the end of and immediately after the haemodialysis session.This publication has 15 references indexed in Scilit:
- Cardiac arrest and sudden death in dialysis unitsKidney International, 2001
- Sudden and cardiac death rates in hemodialysis patientsKidney International, 1999
- Prolongation of the QT Interval and the Sudden Infant Death SyndromeThe New England Journal of Medicine, 1998
- Effect of hemodialysis on the dispersion of the QTc interval.Nephron, 1998
- AbstractJournal of the American College of Cardiology, 1997
- Dispersion of QT interval in patients with and without susceptibility to ventricular tachyarrhythmias after previous myocardial infarctionJournal of the American College of Cardiology, 1995
- QT dispersion and sudden unexpected death in chronic heart failureThe Lancet, 1994
- Relation between ventricular repolarization duration and cardiac cycle length during 24-hour Holter recordings. Findings in normal patients and patients with long QT syndrome.Circulation, 1992
- QT interval prolongation predicts cardiovascular mortality in an apparently healthy population.Circulation, 1991
- QTc prolongation measured by standard 12-lead electrocardiography is an independent risk factor for sudden death due to cardiac arrest.Circulation, 1991