QT intervals in patients receiving a renal transplant

Cardiovascular disease is the most-common cause of mortality in patients with end-stage renal disease and renal transplant. Prolongation of QTc(max) 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.

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, QTc(max)) 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 acidbase alternation was analyzed.

The corrected maximal QT interval (QTc(max)) 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 QTc(max) 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 QTc(max) and serum Ca level (P = .01) in postrenal transplant period.

Renal transplant with normal graft function decrease QTc(max) compared to prehemodialysis and posthemodialysis that may correlate with normalization of electrolytes from the uremic state of the normal kidney function.