Enfermedades cardiovasculares y diagnóstico

The Role of the Vagal Response in Outcomes after Ablation for Atrial Fibrillation

Abstract

Zeng Y, Meng X, Li Y, Xu C and Han J

Objective: The aim of this study was to assess the incremental benefit of denervation of vagal responses for the prevention of recurrence of atrial fibrillation (AF) in patients undergoing a mini-maze procedure. Patients and methods: Between September 2007 and May 2009, 209 patients (aged 53 ± 10 years, 63 male) undergoing cardiac surgery underwent concomitant radiofrequency ablation for persistent AF. Intraoperative highfrequency stimulation showed a positive vagal response in 103 patients and a negative vagal response in 106 patients. The average history of AF was 36 ± 43 months. Preoperatively, 144 patients (68.9%) were in New York Heart Association functional class III or IV. Results: There were no in-hospital deaths, and no significant differences in mortality or complications between the two groups during the postoperative or follow-up periods. Immediately after surgery, 132 patients (63.2%) were in sinus rhythm, with a similar proportion of sinus rhythm in the groups with positive and negative vagal responses (56.3% vs. 62.3%, p=0.38). At the latest follow-up (mean 18.9 ± 9 months), 60.8% of patients had freedom from AF, with a higher proportion of freedom from AF in patients with positive vagal responses than those with negative vagal responses (68.2% vs. 53.3%, p=0.0004). Cox univariate and multivariate analyses identified positive vagal response as a predictor of late recurrence of AF (Wald=9.71; 95% CI, 0.081–0.563; p=0.002). Logistic regression analysis showed that positive vagal response was inversely related to left atrial dimension (Wald=4.45; 95% CI, 0.965–0.999; p=0.035). The proportion of patients with left atrial dimension >70 mm was larger in the group with negative vagal responses than the group with positive vagal responses (48.1% vs. 30.1%, p=0.008). Active ganglionated plexi were found in 49.2% of patients (102/209) with a mean number of 3.6 ± 2.2 sites (range 1–11) per patient. The majority of active sites (78.6%) were located at the pulmonary vein (PV) antrum rather than the PV ostia, including 81.9% of right-sided sites and 70.5% of left-sided sites. Conclusion: The results of this study indicate that parasympathetic attenuation by PV denervation achieved an incremental benefit in patients undergoing PV isolation for AF. In patients with persistent AF, positive vagal response was related to small left atrial diameter, and predicted outcome after ablation.