Cardiac response to hemodialysis with different cardiovascular tolerance: Heart rate variability and QT interval analysis

Abstract

A therapy-specific worsening of cardiovascular stability during bicarbonate dialysis (BD) with respect to acetate-free biofiltration (AFB) have been previously reported. We further investigated the impact of the 2 therapies on electrocardiographic parameters in order to gain novel insight into the cardiac responses. Holter ECG acquired during hypotension-free sessions (12 BD + 12 AFB) were retrospectively analyzed. R-R intervals were extracted from ECG recordings. An autoregressive spectral technique was used to compute low- and high-frequency (LF and HF) components of heart rate variability (HRV). QT interval duration was measured with a computer-assisted technique and corrected for HR. In BD the LF component of HRV after an initial increase was slowly depressed with respect to AFB (p < 0.05). QT duration showed a significant (p < 0.01) hemodialysis-induced reduction. QT shortening was more pronounced (p < 0.05) in BD than in AFB (-31 vs. -10 ms), even after correction for HR (p < 0.05). Cardiac electrical activity is significantly affected by the hemodialysis technique. The decrease in the LF component of HRV and the QT shortening are coherent with the worse cardiovascular tolerance observed in BD and with the hypothesis of an enhanced production of endogenous nitric oxide.

QT Interval and QT Dispersion in Patients Undergoing Hemodialysis: Revisiting the Old Theory

“…Furthermore, the regimen employed in hemodialysis may also play a role in depicting the ‘final scene’ of ventricular repolarization. In this regard, one comparative study reported that bicarbonate dialysis reduces the QT and QTc intervals duration more than acetate-free biofiltration [17]. Since nitric oxide is produced more with the former dialysis regimen as compared with the latter [20], the authors suggested a possible role of nitric oxide in shortening the post-dialysis QT and QTc intervals duration in that study.…”

“…Whereas it has long been believed that a dialysis-induced prolongation of the QTc interval duration – and increase of the QTD – was responsible for lethal ventricular arrhythmias during and immediately following hemodialysis, some emerging evidence suggests a decrease – rather than increase – of the QT and/or QTc interval after dialysis [17, 18, 19]. Patients with end-stage renal disease are a heterogeneous population in which a complex interplay of many factors determines the response of the QTc interval to hemodialysis.…”

“…Since nitric oxide is produced more with the former dialysis regimen as compared with the latter [20], the authors suggested a possible role of nitric oxide in shortening the post-dialysis QT and QTc intervals duration in that study. Nitric oxide excess can depress cardiomyocytes and inhibit vascular smooth muscle cells; these effects were more profound with bicarbonate dialysis [17]. The inverse correlation between nitric oxide and QT interval duration was further demonstrated in the literature [21].…”

Effects of fluid overload on heart rate variability in chronic kidney disease patients on hemodialysis

“…In fact, the studies on HRV in ESRD patients are mainly focused on cardiac death stratification [34], to compare unstable and stable patients on HD [35,36] or to compare different type of treatment [37]. All these studies showed that a reduced HRV is an independent prognostic value of mortality and that HRV analysis permits to identify alterations in autonomic control, such in unstable patients.…”

Comparison of Sustained Low‐Efficiency Dialysis With Acetate‐Free and Acetate‐Containing Bicarbonate Dialysate in Unstable Patients

“…Also, acetate activates the massive release of nitric oxide (NO) by stimulating the synthesis of inducible NO synthase, which causes vasodilatation. The clinical manifestation of the accumulation of acetate in blood is a decrease in arterial pressure and an increase in heart rate .…”