QT interval abnormalities and heart rate variability in patients with cirrhosis.

Background And Study Aims: We aimed to assess the relationship of the QT interval and heart rate variability with the severity and aetiology of cirrhosis and determine the effect of propranolol on them.

Patients And Methods: This prospective study included 44 patients with cirrhosis categorised into three groups based on the Child-Pugh score: groups 1, 2 and 3 (with 12, 15 and 15 patients, respectively). Demographic characteristics, propranolol administration, severity of cirrhosis evaluated by the Child-Pugh score, aetiology of cirrhosis, and serum sodium, potassium and calcium levels were evaluated. All patients underwent 24 h-Holter monitoring. Corrected QT interval (QTc), average heart rate, standard deviation of normal-to-normal intervals (SDNN) and corrected SDNN (cSDNN) were evaluated.

Results: The average QTc was significantly longer in group 3 than in groups 1 and 2 (453.4 ± 17.4 vs 422.8 ± 18.6 and 428.9 ± 17.24 ms, p < 0.001). The median SDNN was 70 ms and was significantly lower in group 3 vs groups 1 and 2 (77; interquartile range [IQR], 67-89.5 vs 57; IQR, 38-68 and 75 ms; IQR, 61-81 ms, p = 0.003). cSDNN was significantly lower in group 3 vs groups 1 and 2 (200.0 ± 42.6 vs 254.5 ± 75.3 and 277.8 ± 110.6 ms, p = 0.022). Propranolol administration resulted in a significant increase in the average SDNN value but had no effect on cSDNN or QTc. QTc was associated with the Child-Pugh class (p < 0.001), viral aetiology (p = 0.009) and sex (p = 0.010); SDNN was associated with the mean heart rate (p = 0.015) and Child-Pugh class (p = 0.024).

Conclusion: QTc interval prolongation and decreased SDNN are common in cirrhosis. Their prevalence is closely associated with disease severity. Propranolol has no effects on cSDNN or QTc.