title: Late arrhythmia in adults with the mustard procedure for transposition of great arteries: a surrogate marker for right ventricular dysfunction?
abstract: OBJECTIVE
  To examine the relation between ventricular dysfunction and late clinical arrhythmia in adults who underwent the Mustard procedure for transposition of the great arteries.
  
  
  METHODS
  Observational study based on periodic outpatient assessment of biventricular function.
  
  
  METHODS
  Tertiary referral centre.
  
  
  METHODS
  Analysis of data from 12 lead ECGs, echocardiography, exercise radionuclide ventriculography, and magnetic resonance imaging.
  
  
  METHODS
  Clinical outcome and late onset clinical arrhythmia during follow up. ECG and ventricular function indices obtained before arrhythmia onset were used for analysis.
  
  
  RESULTS
  51 patients (mean (SD) age 25.7 (5.0) years) fulfilled entry criteria at a mean of 23.4 (4.0) years after the Mustard procedure. Late arrhythmia occurred in 11 (22%): sustained atrial flutter/fibrillation in 10, ventricular tachycardia in one. Compared with patients who remained arrhythmia free, patients with arrhythmia had longer QRS (129 (26) v 112 (16) ms, p = 0.01), greater QT dispersion (107 (28) v 51 (24) ms, p < 0.001), and increased ratio of right to left ventricular end diastolic diameter (2.4 (0.9) v 1.7 (0.7), p = 0.02), but no difference in wall thickness. Systemic ejection fraction was also reduced in the arrhythmia subgroup (at rest: 34.1 (13)% v 47 (16)%, p = 0.04; during exercise: 37.8 (12)% v 52 (17)%, p = 0.03). QRS duration correlated with right ventricular end diastolic diameter (r = 0.59, p < 0.001), suggesting a possible mechano-electric relation after the Mustard procedure. QT dispersion was the only predictor of clinical arrhythmia in multivariate analysis.
  
  
  CONCLUSIONS
  Impaired ventricular function in adults with the Mustard procedure for transposition of the great arteries relates to clinical arrhythmia. Late atrial flutter/fibrillation may be a surrogate marker for ventricular dysfunction, and these patients may also be at risk of ventricular tachycardia.
authors.affiliation: University of Toronto, Congenital Cardiac Centre For Adults, The Toronto Hospital Department of Medicine, Ontario, Canada. m.gatzoulis@rbh.nthames.nhs.uk
authors.forename: M A
authors.initials: MA
authors.lastname: Gatzoulis
authors.forename: J
authors.initials: J
authors.lastname: Walters
authors.forename: P R
authors.initials: PR
authors.lastname: McLaughlin
authors.forename: N
authors.initials: N
authors.lastname: Merchant
authors.forename: G D
authors.initials: GD
authors.lastname: Webb
authors.forename: P
authors.initials: P
authors.lastname: Liu
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology*; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D016016:Proportional Hazards Models; D015635:Radionuclide Ventriculography; D014188:Transposition of Great Vessels / Q000150:complications / Q000601:surgery*; D018497:Ventricular Dysfunction, Right / Q000150:complications* / Q000175:diagnosis