Diurnal variation and dispersion in QT interval in cirrhosis: Relation to haemodynamic changes

Background/Aims A long QTC interval has been described in a substantial fraction of patients with cirrhosis, but information on QT variation and dispersion is sparse. The aim was to determine QT variation with time and QT dispersion (QTdisp). Methods The study population comprised 23 patients with cirrhosis, undergoing a haemodynamic investigation. 24-h 12 lead Holter monitoring provided information on QT and heart rate variability. Results Mean QTC was above upper normal limit (440 ms1/2) in eleven patients (47%) and significantly higher than in controls (441 vs 400 ms1/2, p < 0.01). The minimum value of QTC (but not the maximum value) showed a significant diurnal variation both in cirrhosis and controls. QTdisp in cirrhosis and controls was similar (33 vs 36 ms, ns), but related to indicators of liver dysfunction, central circulation time, and arterial blood pressure (r = 0.44–0.58, p = 0.03–0.001). No diurnal variation of QTdisp was found in cirrhosis. Heart rate variability was reduced with a significant relation to central hypovolaemia (r = 0.55, p = 0.01). Conclusions Twenty-four hours QTC is prolonged in a substantial fraction of patients with cirrhosis, but with normal diurnal variation. The combination of long QTC and normal QTdisp suggests delayed myocyte repolarisation on the cellular level, rather than temporal and spatial heterogeneity in the myocardial wall.