Mechanism and ablation of arrhythmia following total cavopulmonary connection

The ability to identify and ablate different arrhythmia mechanisms after the total cavopulmonary connection has not been studied in detail.

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%).

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.