Prolongation of QTc interval: relationship with etiology and severity of liver disease, mortality and liver transplantation.

Abstract

A prolonged QTc interval has been reported in patients with liver disease. The objectives of our study were to determine whether a prolonged QTc interval was an independent predictor of mortality in patients with cirrhosis and to examine the effect of liver transplantation (LT) on QTc interval. We retrospectively studied two cohorts of patients - QTc interval was measured in 409 patients (pre-transplant group), and in 162 patients (transplant group) before and 6 months after LT. QT interval (mean) corrected (QTc) for ventricular rate was read from a 12-lead EKG. Patients with known cardiovascular disease or other risk factors that are known to cause a prolonged QTc interval were excluded. Pre-transplant group. One hundred and sixty-two patients (40%) had a prolonged QTc interval (>440 ms). By binary logistic regression, age (P=0.005), alcoholic cirrhosis (P=0.007) and Child-Pugh scores (P=0.007) were independent predictors of prolonged QTc interval. Sixty-six patients died during a mean follow-up of 8.9 years. Although the Kaplan-Meier survival curve showed a lower survival in patients with a prolonged QTc interval (P=0.03 by log rank test), when survival was adjusted for the Child-Pugh score by Cox regression survival analysis, there were no survival differences in patients with and without prolonged QTc interval. Cox regression analysis showed that the Child-Pugh score (hazard ratio 1.5, CI 1.3-1.6, s<0.001) was the only independent predictor of survival. Transplant group. In this cohort, 91 patients (56%) had prolonged QTc (>440 ms) before LT. Mean QTc improved significantly after LT (429 +/- 29 ms vs. 450 +/- 39 ms P<0.002). Of the 91 patients with prolonged QTc, 50 (55%) normalized, three (3.3%) remained unchanged, 12 (13.3%) showed further prolongation, and 26 (28%) showed improvement but remained above normal limits. An additional nine patients who had normal QTc before LT developed prolonged QTc (>440 ms) after LT. A prolonged QTc interval was common in patients with cirrhosis, but its presence had no independent effect on mortality. Prolonged QTc returns to normal values in about half of the patients after LT, suggesting that liver disease plays a role, but may not be the only factor in the pathogenesis of prolonged QTc.