Objectives: The aim of this study was to evaluate irrigated-tip catheter for ablation of intraatrial reentrant tachycardias late after surgical repair of congenital heart disease.
Background: In congenital heart disease patients, the right atrium can be markedly enlarged with areas of low blood flow. Radiofrequency (RF) lesion creation may be hampered by insufficient electrode cooling at sites with low blood flow.
Methods: Thirty-six consecutive patients with intraatrial reentrant tachycardia refractory to antiarrhythmic therapy from two centers were included in the study. Entrainment pacing and electroanatomic mapping (CARTO) were used to delineate reentrant circuits and critical isthmus sites. RF ablation was performed using an irrigated-tip catheter (Navistar Thermocool).
Results: Fifty-two intraatrial reentrant tachycardia circuits were identified, and 48 were targeted with RF ablation. RF ablation was performed using a mean of 13 +/- 11 irrigated RF applications per tachycardia isthmus with a mean power of 36 +/- 8 W. In a historical control group of congenital heart disease patients managed with conventional catheter ablation, the number of lesions per isthmus was higher (23 +/- 11) and mean power was lower (27 +/- 14 W). Acute success was achieved in 45 intraatrial reentrant tachycardias (94% of targeted tachycardias and 87% of all tachycardias). After a mean follow-up of 17 +/- 7 months, 33 (92%) of 36 patients were free of recurrence. Five patients (14%) developed paroxysmal atrial fibrillation.
Conclusions: The combination of modern techniques including electroanatomic mapping and catheter irrigation allows safe and highly effective ablation of intraatrial reentrant tachycardia in patients with surgically repaired congenital heart disease.