title: Q-T interval (QT(C)) in patients with cirrhosis: relation to vasoactive peptides and heart rate.
abstract: OBJECTIVE
  Prolonged Q-T interval (QT) has been reported in patients with cirrhosis who also exhibit profound abnormalities in vasoactive peptides and often present with elevated heart rate (HR). The aim of this study was to relate QT to the circulating level of endothelins (ET-1 and ET-3) and calcitonin gene-related peptide (CGRP) in patients with cirrhosis. In addition, we studied problems with HR correction of QT.
  
  
  METHODS
  Forty-eight patients with cirrhosis and portal hypertension were studied during a haemodynamic investigation. Circulating levels of ETs and CGRP were determined by radioimmunoassays. Correction of QT for HR above 60 beats per min was performed using the methods described by Bazett (QT(C)) and Fridericia (QT(F)).
  
  
  RESULTS
  Prolonged QT(C) (above 440 ms), found in 56% of the patients, was related to the presence of significant portal hypertension and liver dysfunction (p < 0.05 to 0.001), but not to elevated ET-1, ET-3 or CGRP. When corrected according to Bazett, QT(C) showed no significant relation to differences in HR between patients (r = 0.07, ns). QTF showed some undercorrection of HR (r = -0.36; p < 0.02). During HR variation in the individual patient, QT(C) revealed a small but significant overcorrection (2.6 ms per heartbeat per min; p < 0.001). This value was significantly (p < 0.02) smaller with QTF (1.2 ms per heartbeat per min).
  
  
  CONCLUSIONS
  The prolonged QT(C) in cirrhosis is related to liver dysfunction and the presence of portal hypertension, but not to the elevated powerful vasoconstrictor (ET-1) or vasodilator (CGRP, ET-3) peptides. The problems with correction of the QT for elevated HR in cirrhosis are complex, and the lowest HR should be applied for determination of the QT.
authors.affiliation: Department of Clinical Physiology 239 and Gastroenterology 439, H:S Hvidovre Hospital, University of Copenhagen, Denmark. jens.h.henriksen@hvh.regionh.dk
authors.forename: J H
authors.initials: JH
authors.lastname: Henriksen
authors.forename: V
authors.initials: V
authors.lastname: Gülberg
authors.forename: S
authors.initials: S
authors.lastname: Fuglsang
authors.forename: S
authors.initials: S
authors.lastname: Schifter
authors.forename: F
authors.initials: F
authors.lastname: Bendtsen
authors.forename: A L
authors.initials: AL
authors.lastname: Gerbes
authors.forename: S
authors.initials: S
authors.lastname: Møller
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D015740:Calcitonin Gene-Related Peptide / Q000097:blood*; D002304:Cardiac Pacing, Artificial; D002395:Catecholamines / Q000097:blood; D004562:Electrocardiography; D019332:Endothelin-1 / Q000097:blood; D019334:Endothelin-3 / Q000097:blood; D016232:Endothelins / Q000097:blood*; D005260:Female; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D006975:Hypertension, Portal / Q000150:complications*; D008103:Liver Cirrhosis / Q000150:complications*; D008133:Long QT Syndrome / Q000097:blood / Q000175:diagnosis* / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values
chemical_list: D002395:Catecholamines; D019332:Endothelin-1; D019334:Endothelin-3; D016232:Endothelins; D015740:Calcitonin Gene-Related Peptide