QT Intervals in Patients Receiving a Renal Transplant

Abstract

Objectives: Cardiovascular disease is the most-common cause of mortality in patients with end-stage renal disease and renal transplant. Prolongation of QTcmax and QTc dispersion are risk factors of cardiac arrhythmias and mortality. This study compares the changes of QT parameters before hemodialysis, after hemodialysis, and after renal transplant.

Materials and Methods: Patient candidates for renal transplant were selected. Mean serum electrolyte and 12-lead electrocardiogram were recorded (1) immediately, (2) before and, (3) after the last dialysis session before renal transplant, (4) and 2 weeks after a kidney transplant in 34 patients with normal graft function (plasma Cr ≤ 176.8 µmol/L). Each QT interval was corrected for the patient’s heart rate using Bazett’s formula. The QT parameters (QTd, QTcd, QTcmax) were compared between prehemodialysis, post­hemodialysis, and 2 weeks after renal transplant using a paired t test and a general liner model repeated measure. The correlation between QT parameter changes and serum electrolyte and acid-base alternation was analyzed.

Results: The corrected maximal QT interval (QTcmax) decreased significantly after successful renal transplant compared to prehemodialysis (P = .002) and posthemodialysis (P = .003) with a paired t test and a General Liner Model Repeated Measure (P < .001) between the 3 groups. Also, the mean of QTcmax decreased significantly after renal transplant (P = .001) compared to what it was before hemodialysis and after hemodialysis. There was a significant correlation (r= -0.37) between reduction of QTcmax and serum Ca level (P = .01) in postrenal transplant period.

Conclusions: Renal transplant with normal graft function decrease QTcmax compared to pre­hemodialysis and posthemodialysis that may correlate with normalization of electrolytes from the uremic state of the normal kidney function.