Diurnal variation and dispersion in QT interval in cirrhosis: relation to haemodynamic changes.
OBJECTIVE
A long QT(C) 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 (QT(disp)).


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 QT(C) was above upper normal limit (440 ms(1/2)) in eleven patients (47%) and significantly higher than in controls (441 vs 400 ms(1/2), p<0.01). The minimum value of QT(C) (but not the maximum value) showed a significant diurnal variation both in cirrhosis and controls. QT(disp) 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 QT(disp) 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 QT(C) is prolonged in a substantial fraction of patients with cirrhosis, but with normal diurnal variation. The combination of long QT(C) and normal QT(disp) suggests delayed myocyte repolarisation on the cellular level, rather than temporal and spatial heterogeneity in the myocardial wall.
Hansen
Stig
S
Department of Clinical Physiology, 239, H:S Hvidovre Hospital, University of Copenhagen, DK-2650 Hvidovre, Denmark.
Møller
Søren
S
Bendtsen
Flemming
F
Jensen
Gorm
G
Henriksen
Jens H
JH
D000368:Aged; D001775:Blood Circulation; D001794:Blood Pressure; D001810:Blood Volume; D002940:Circadian Rhythm; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D020896:Hypovolemia / Q000209:etiology / Q000503:physiopathology; D008099:Liver / Q000503:physiopathology; D008103:Liver Cirrhosis / Q000150:complications* / Q000503:physiopathology; D008133:Long QT Syndrome / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D013997:Time Factors