Sauer WH et al. (2006) Atrioventricular nodal reentrant tachycardia in patients referred for atrial fibrillation ablation. Circulation 114: 191–195

Atrioventricular nodal re-entrant tachycardia (AVNRT) can trigger atrial fibrillation (AF), but the incidence of AVNRT as a cause of AF is unclear. Identification of patients with AVNRT could improve the choice of catheter ablation strategy employed for AF. To determine the incidence of AVNRT-induced AF, Sauer et al. studied 629 consecutive patients referred for catheter ablation of AF from November 1998 to March 2005.

Inducible AVNRT was found in 24 patients at the initial procedure, and in a further 3 patients upon presentation for repeat ablation (4.3% in total). None of the patients with AVNRT had a history of regular palpitations or regular narrow complex tachycardia. Patients with AVNRT tended to be younger than those without. In 13 patients, AVNRT was the only observed trigger for AF; these patients did not, therefore, undergo pulmonary vein isolation following slow-pathway modification. After a mean follow-up of 21.4 months, 21 (87.5%) of the 24 patients initially identified with AVNRT had no recurrent AF, and no longer required antiarrhythmic medication. By contrast, only 329 (54.7%) patients without AVNRT were cured of AF after a single procedure. Slow-pathway modification for AVNRT resolved the AF in the three patients in whom AVNRT was identified at second procedure.

The authors conclude that the success rate for curing AF is higher in patients with AVNRT than in those without, and that in a subset of patients resolving AVNRT is sufficient to cure AF. That three patients required a second visit before discovery of AVNRT emphasizes the need to ensure correct diagnosis, say the authors, especially as treatment for AVNRT cured AF in these patients.