Mechanism and ablation of arrhythmia following total cavopulmonary connection.

BACKGROUND: The ability to identify and ablate different arrhythmia mechanisms after the total cavopulmonary connection has not been studied in detail. METHODS AND
RESULTS: After obtaining Institutional Review Board approval according to institutional guidelines, consecutive patients after a total cavopulmonary connection undergoing electrophysiology study over a 6-year period were included (2006-2012). Arrhythmia mechanism was determined, and the procedural outcome was defined as complete, partial success, or failure. A 12-point arrhythmia severity score was calculated for each patient at baseline and on follow-up. Fifty-seven procedures were performed on 52 patients (18.4 ± 11.8 years; 53.0 ± 27.2 kg). Access to the pulmonary venous atrium was necessary in 33 procedures, via fenestration (16) or transbaffle puncture (17), and in 2 cases, an additional retrograde approach was used. In total, 80 arrhythmias were identified in 47 cases: macroreentrant (n = 25) or focal atrial tachycardia (n = 8), atrioventricular nodal reentry tachycardia (n = 13), reentry via an accessory pathway (n = 4) or via twin atrioventricular nodes (n = 4), ventricular tachycardia (n = 5), and undefined atrial tachycardia (n = 21). Procedural outcome in 32 patients who underwent ablation was complete success (n = 25), partial success (n = 3), failure (n = 3), or empirical ablation (n = 1). After successful ablation, there was a significant decrease in arrhythmia score over 18.2 (4-32) months follow-up, with a sustained trend even in the face of arrhythmia recurrence (50%).
CONCLUSIONS: Arrhythmia mechanism post total cavopulmonary connection is highly varied, encompassing simple and more complex substrates, documentation of which facilitates a strategic approach to invasive arrhythmia management. Despite the anatomic limitations, successful and clinically meaningful ablation is possible.