title: Exercise-induced ventricular re-polarisation changes in moderate congenital aortic valve stenosis.
abstract: Introduction Pressure overload increases in patients with moderate aortic valvular stenosis during exercise. In the absence of symptoms, it remains difficult, however, to discriminate patients for surgery based only on pressure overload. Other parameters, such as the dispersion of ventricular re-polarisation (d-QT), which reportedly increases with the transvalvular pressure gradient, have not been fully studied in this condition.
  
  
  OBJECTIVE
  To determine the pattern of QT and d-QT response to exercise testing in children with moderate aortic valve stenosis in order to evaluate the impact of pressure overload from an electrophysiological perspective. Materials and methods In all, 15 patients were compared with 15 controls paired for age (14.8±2.5 versus 14.2±1.5 years old) and gender (66.7% male). All the patients underwent exercise stress testing with 12-lead electrocardiograph recording. QT was measured from the onset of QRS to the apex (QTa) at rest, at peak exercise, and at 1 and 3 minutes upon recovery. QT was corrected using the Fridericia equation, and d-QT was calculated.
  
  
  RESULTS
  Resting QTc was similar among the study groups, but increased significantly in study patients compared with the control group at maximal effort (p=0.004) and after 1 (p<0.001) and 3 (p<0.001) minutes of recovery. A significant association was identified between groups for d-QT (p=0.034), and post-hoc tests revealed a significant difference only at rest (p=0.001).
  
  
  CONCLUSIONS
  Ventricular re-polarisation abnormalities can be unmasked and highlighted by the assessment of electrical re-polarisation during exercise challenge in patients with asymptomatic moderate aortic valve stenosis. Using QT response to exercise could be beneficial for better optimisation of risk stratification in these patients.
authors.affiliation: 1Kinesiology Department,University of Montreal,Montreal,Qc,Canada.
authors.forename: Louis-Simon
authors.initials: LS
authors.lastname: Beauséjour
authors.affiliation: 1Kinesiology Department,University of Montreal,Montreal,Qc,Canada.
authors.forename: Hugo
authors.initials: H
authors.lastname: Gravel
authors.affiliation: 2Department of Pediatrics,Division of Cardiology,CHU Ste-Justine,University of Montreal,Montreal,Qc,Canada.
authors.forename: Wadi
authors.initials: W
authors.lastname: Mawad
authors.affiliation: 2Department of Pediatrics,Division of Cardiology,CHU Ste-Justine,University of Montreal,Montreal,Qc,Canada.
authors.forename: Nagib
authors.initials: N
authors.lastname: Dahdah
authors.affiliation: 1Kinesiology Department,University of Montreal,Montreal,Qc,Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Curnier
mesh_terms: D000293:Adolescent; D001024:Aortic Valve Stenosis / Q000151:congenital / Q000000981:diagnostic imaging / Q000503:physiopathology*; D015150:Echocardiography, Doppler; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000503:physiopathology*; D006801:Humans; D008297:Male; D012146:Rest / Q000502:physiology; D012189:Retrospective Studies; D012720:Severity of Illness Index
keywords: Aortic stenosis; QTc; d-QT; exercise test; ventricular re-polarisation