QT interval analysis in patients with chronic liver disease: a prospective study

In previous studies, it has been shown that QT interval prolongation is related to an increased mortality rate in chronic liver disease (CLD). But QT dispersion (QTd) and its clinical significance in CLD has not been well studied. The objectives of this study were to investigate the relation between QTd and severity of the disease and determine its prognostic value in cirrhotic patients. Thirty-three consecutive patients with cirrhosis and 35 sex- and age-matched healthy subjects were studied. QT intervals and QT dispersions were measured on admission, and all intervals were corrected for heart rate according to Bazett's formula. The authors analyzed the potential relationship between QT parameters and the disease severity according to Child-Pugh classification and compared these values between survivors and nonsurvivors after a 3-year follow-up. Child-Pugh classification is used to assess liver function in cirrhosis. Corrected QT (QTc) prolongations were found in 32% of patients with cirrhosis and 5.7% of the healthy controls (p <0.001). The prevalence of increased (>70 ms) corrected QT dispersion (QTcd) was 45% in patients with cirrhosis. According to Child-Pugh criteria: QTd, maximum QT interval (QTmax), corrected QTmax (QTcmax), and QTcd in class C were significantly higher than those of class A and B (p <0.05, for all comparison). But there was no significant difference between class A and B in QTmax, QTcmax, QTd, and QTcd. There were 10 (30%) deaths from all causes during 3-year follow-up in the study group. Cox regression analysis showed that QTd and QTcd were better mortality indicators than QTmax and QTcmax, and Child's classification was the best predictor for mortality among all variables. In conclusion, QT dispersion and corrected QT dispersion parameters were better mortality indicators than other QT interval parameters and also may give additional prognostic information in patients with chronic liver disease.