200 Clinical significance of atrial fibrillation occurrence during catheter ablation of the slow pathway

Abstract

Atrial fibrillation (AF) occurrence during electrophysiological study (EPS) for ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) is not rare, but its significance is unknown. The purpose of the study was to evaluate the factors of risk of AF induction during AVNRT ablation and its prognostic significance. 397 patients (pts), 115 men, 282 women aged from 14 to 88 years with recurrent AVNRT's and indication of ablation were studied. AVNRT was initially induced by atrial stimulation. Radiofrequency (RF) ablation of the slow pathway was performed and atrial stimulation repeated. Clinical data of pts with AF induction during the procedure were collected. AF was noted in 68 pts (17%), either induced by stimulation or spontaneous during the application of RF energy. The AF occurrence was significantly correlated with a history of hypertensive disease (HTD) (p<0.0005), of spontaneous AF before the ablation (p <0.001). There was no correlation with the sex, age and the presence of associated heart disease except the HTD. During the follow-up, 17 pts (4%) developed spontaneous AF; 10 of them had presented AF during AVNRT ablation, which was significantly (p <0.0008) associated with a risk of AF after the procedure. Bivariate analysis indicated a significant correlation between AF occurrence and the female gender with HTD (p <0.00001) or history of AF before ablation (p<0.00001) and the development of AF after ablation (p <0.00001), a significant correlation between AF occurrence and an age > 50 years associated with HTD (p<0.00001), or AF before ablation (p <0.00001) and the development of AF after the procedure (p <0.00001). There was no significant correlation between AF occurrence in males and pts younger than 51 years with HTD or history of AF before ablation. AF occurrence after ablation remains more frequent than in pts without AF during the procedure. AF occurrence during the catheter ablation of AVNRT is significantly correlated with the presence of hypertensive disease, history of AF before ablation and the occurrence of AF after ablation. The correlation is mainly noted in women and patients aged more than 50 years.