Catheter Ablation of Atrial Fibrillation Raises the Plasma Level of NGF-β Which Is Associated with Sympathetic Nerve Activity

PURPOSE: The expression of nerve growth factor-β (NGF-β) is related to cardiac nerve sprouting and sympathetic hyper innervation. We investigated the changes of plasma levels of NGF-β and the relationship to follow-up heart rate variability (HRV) after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). MATERIALS AND METHODS: This study included 147 patients with AF (117 men, 55.8±11.5 years, 106 paroxysmal AF) who underwent RFCA. The plasma levels of NGF-β were quantified using double sandwich enzyme linked immunosorbent assay method before (NGF-β(pre)) and 1 hour after RFCA (NGF-β(post-1hr)). HRV at pre-procedure (HRV(pre)), 3 months (HRV(post-3mo)), and 1 year post-procedure (HRV(post-1yr)) were analyzed and compared with plasma levels of NGF-β. RESULTS: 1) The plasma levels of NGF-β significantly increased after RFCA (20.05±11.09 pg/mL vs. 29.60±19.43 pg/mL, p<0.001). The patients who did not show increased NGF-β(post-1hr) were older (p=0.023) and had greater left atrial volume index (p=0.028) than those with increased NGF-β(post-1hr). 2) In patients with NGF-β(pre) >18 pg/mL, low frequency components (LF)/high-frequency components (HF) (p=0.003) and the number of atrial premature contractions (APCs, p=0.045) in HRV(post-3mo) were significantly higher than those with ≤18 pg/mL. 3) The LF/HF at HRV(post-3mo) was linearly associated with the NGF-β(pre) (B=4.240, 95% CI 1.114-7.336, p=0.008) and the NGF-β(post-1hr) (B=7.617, 95% CI 2.106-13.127, p=0.007). 4) Both NGF-β(pre) (OR=1.159, 95% CI 1.045-1.286, p=0.005) and NGF-β(post-1hr) (OR=1.098, 95% CI 1.030-1.170, p=0.004) were independent predictors for the increase of LF/HF at HRV(post-3mo). CONCLUSION: AF catheter ablation increases plasma level of NGF-β, and high plasma levels of NGF-β(pre) was associated with higher sympathetic nerve activity and higher frequency of APCs in HRV(post-3mo).