Electrocardiographic Abnormalities and QTc Interval in Patients Undergoing Hemodialysis

Abstract

BackgroundSudden cardiac death is one of the primary causes of mortality in chronic hemodialysis (HD) patients. Prolonged QTc interval is associated with increased rate of sudden cardiac death. The aim of this article is to assess the abnormalities found in electrocardiograms (ECGs), and to explore factors that can influence the QTc interval.MethodsA total of 141 conventional HD patients were enrolled in this study. ECG tests were conducted on each patient before a single dialysis session and 15 minutes before the end of dialysis session (at peak stress). Echocardiography tests were conducted before dialysis session began. Blood samples were drawn by phlebotomy immediately before and after the dialysis session.ResultsBefore dialysis, 93.62% of the patients were in sinus rhythm, and approximately 65% of the patients showed a prolonged QTc interval (i.e., a QTc interval above 440 ms in males and above 460ms in females). A comparison of ECG parameters before dialysis and at peak stress showed increases in heart rate (77.45±11.92 vs. 80.38±14.65 bpm, p = 0.001) and QTc interval (460.05±24.53 ms vs. 470.93±24.92 ms, p<0.001). After dividing patients into two groups according to the QTc interval, lower pre-dialysis serum concentrations of potassium (K+), calcium (Ca2+), phosphorus, calcium* phosphorus (Ca*P), and higher concentrations of plasma brain natriuretic peptide (BNP) were found in the group with prolonged QTc intervals. Patients in this group also had a larger left atrial diameter (LAD) and a thicker interventricular septum, and they tended to be older than patients in the other group. Then patients were divided into two groups according to ΔQTc (ΔQTc = QTc peak-stress- QTc pre-HD). When analyzing the patients whose QTc intervals were longer at peak stress than before HD, we found that they had higher concentrations of Ca2+ and P5+ and lower concentrations of K+, ferritin, UA, and BNP. They were also more likely to be female. In addition, more cardiac construction abnormalities were found in this group. In multiple regression analyses, serum Ca2+ concentration before HD and LAD were independent variables of QTc interval prolongation. UA, ferritin, and interventricular septum were independent variables of ΔQTc.ConclusionProlonged QT interval is very common in HD patients and is associated with several risk factors. An appropriate concentration of dialysate electrolytes should be chosen depending on patients’ clinical conditions.

A phase 1b randomized, placebo‐controlled clinical trial with SNF472 in haemodialysis patients

“…Electrocardiogram, QTcB intervals and ionized calcium levels were extensively evaluated throughout this study and showed no safety issues associated with treatment with the study drug in the HD patient population. Moreover, disturbance of QT prolongations are frequent findings among patients with chronic kidney disease, especially in ESRD patients on HD . A negative correlation has been established between Ca, P and K and QT/QTc interval increase in dialysis .…”

Changes in QTc interval in long-term hemodialysis patients

“…To date, numerous studies have utilized QT or QTc interval in drug trials or cardiological investigations. In many of them, QTc interval was divided into two gender-specific categories: normal and prolonged, however the cutoff points were to some extent arbitrary [6, 21–23]. In some papers, the cutoff points for women were 10 to 20 ms longer than those for men [6, 23, 24].…”

“…Current analyses of clinically relevant variables on QTc interval at 1 year after HD initiation revealed that the corrected calcium levels before dialysis were a possible predictor of QTc interval prolongation. Several studies have suggested that a low calcium concentration of serum or dialysate and rapid reduction of serum calcium concentrations during HD session may lead to prolongation of QTc interval, possibly resulting in SCD [11, 23, 26]. Alternatively, because serum ionized calcium levels regulate the contractility of cardiac myocytes and vascular smooth muscle, hypocalcemia or rapid lowering of serum calcium levels during dialysis may contribute to hypotension and reduction of coronary blood flow and subsequent fatal myocardial ischemia.…”

Electrocardiographic abnormalities among late-stage non-dialysis chronic kidney disease patients

“…Study by Yadla and Poosa showed that prolonged QTc was found in 13.3% of CKD population [13]. Nie et al showed that 65% of patient undergoing hemodialysis (HD) had prolonged QTc interval [15]. These ECG markers are also useful to detect silent CV disease in the CKD setting [16].…”