Impact of atrial fibrillation ablation on cardiac sympathetic nervous system in patients with and without heart failure

Background/objectivesCatheter ablation of atrial fibrillation (AF) might influence the cardiac autonomic nervous system. To investigate the impact of catheter ablation on the sympathetic nervous function in AF patients with and without heart failure (HF) using cardiac iodine-123-metaiodobenzylguanidine (123I-mIBG) scintigraphy, and the association of this effect with AF recurrence.MethodsForty consecutive patients (median age, 65 (54-69) years; male, 29) with paroxysmal (n = 22) and persistent (n = 18) AF who were scheduled for ablation were enrolled. Twelve (30%) of these patients also exhibited either stable HF, defined as an ejection fraction < 40%, or a history of symptomatic HF. 123I-mIBG scintigraphy was performed at baseline and 3 months post-ablation. The heart-to-mediastinum ratio of 123I-mIBG uptake at 15 min (H/M15 min) and 240 min (H/M240 min), as well as the washout rate (WR) were measured.ResultsDuring an 11 ± 4-month follow-up, AF recurrence was observed in 8 (20%) patients receiving no antiarrhythmic drugs. Patients with HF had a tendency toward a lower baseline H/M15 min (1.91 ± 0.06 vs. 2.05 ± 0.04, p = 0.07), significantly lower H/M240 min (1.88 ± 0.22 vs. 2.14 ± 0.28, p = 0.008), and higher WR (40.3 ± 9.0 vs. 32.3 ± 7.4, p = 0.007). Post-ablation, WR decreased in patients with HF (40.2 ± 8.5 to 29.0 ± 8.9, p = 0.02) but slightly increased in those without (32.0 ± 7.4 to 34.6 ± 10.3, p = 0.04). WR post-ablation independently predicted AF recurrence (adjusted hazard ratio = 1.14 for 1 percentage point increase in the WR, 95% coincidence interval = 1.02-1.34, p = 0.02).ConclusionsAF ablation restores sympathetic nervous system status via attenuation of excessive adrenergic tone in HF patients. Elevated sympathetic nervous tone 3 months post-ablation was a reliable predictor of AF recurrence.