Late arrhythmia in adults with the Mustard procedure for transposition of great arteries: a surrogate marker for right ventricular dysfunction?

Objective-To examine the relation between ventricular dysfunction and late clinical arrhythmia in adults who underwent the Mustard procedure for trans position of the great arteries. Design-Observational study based on periodic outpatient assessment of biven tricular function. Setting-Tertiary referral centre. Interventions-Analysis of data from 12 lead ECGs, echocardiography, exercis e radionuclide ventriculography, and magnetic resonance imaging. Main outcome measures-Clinical outcome and late onset clinical arrhythmia d uring follow up. ECG and ventricular function indices obtained before arrhy thmia onset were used for analysis. Results-51 I patients (mean (SD) age 25.7 (5.0) years) fulfilled entry crit eria at a mean of 23.4 (4.0) years after the Mustard procedure. Late arrhyt hmia occurred in 11 (22%): sustained atrial flutter/fibrillation in 10, ven tricular 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 incre ased 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 ejecti on fraction was also reduced in the arrhythmia subgroup tar 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 arrhyt hmia in multivariate analysis. Conclusions-Impaired ventricular function in adults with the Mustard proced ure 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 tachyc ardia.