Activated Sympathetic Nerve Function May Indicate the Progression of Atrial Fibrillation

Abstract

Background: It has been reported that activated sympathetic nerve function (SNF) has profound influences on the electrical aspect of cardiac function. The purpose of this study is to investigate whether the progression of atrial fibrillation (AF) is associated with activated SNF. Methods: Twenty-four patients (62.6±5.6 y.o., male/female=14⁄10) who were including 12 patients with paroxysmal AF (G1) and 12 patients with persistent/permanent AF (G2) were investigated. They had normal LV function (EF=64.4±5.4%) and no severe cardiac disease. We estimated brain-natriuretic-peptide (BNP), echocadiographic parameters (LAD, LVEF, LVDd, LAA-flow) and SNF which was measured using early and delayed heat-to-mediatinum (H/M)-ratio and washout rate (WR) on I-123-MIBG imaging. Results: There were no differences in LVEF, LVDd, early H/M-ratio between both groups. BNP was elevated in G2 than in G1 (G1: 55±47 pg/ml vs. G2: 250±196 pg/ml; p<0.01). LAD was larger in G2 than in G1 (G1: 41±6 mm vs. G2: 51±6 mm; p<0.01) and LAA-flow was lower in G2 than in G1 (G1: 61±21 cm/sec vs. G2: 38±15 cm/sec; p<0.01). Furthermore, delayed H/M-ratio was lower in G2 than in G1 (G1: 2.2±0.2 vs. G2: 1.9±0.1; p<0.01) and WR was higher in G2 than in G1 (G1: 16±5.0% vs. G2: 31±9.6%; p<0.01). Conclusion: These results suggest that the progression of AF is associated with activated SNF as well as LA dysfunction. Activated SNF may indicate the progression of AF.