Abstract 726: Cardiac Sympathetic Nerve System Abnormality Predicts Long-Term Outcome in Patients with Paroxysmal Atrial Fibrillation who did not have Conventional Risk Factors
Backgrounds: A history of structural heart disease, heart failure, or stroke increases mortality in patients with atrial fibrillation (AF). However, a useful marker for predicting mortality is not clarified in AF patients without those conventional risks. We recently reported cardiac sympathetic nerve system (SNS) abnormality as a predictor of arrhythmogenic mortality. We hypothesized that SNS abnormality would be associated with increased mortality in patients with paroxysmal AF who didn’t have conventional risk factors.
Methods and Results: Iodine-123 metaiodobenzylguanidine scintigraphy was performed to measure Heart/Mediastinum (H/M) ratio as SNS activity in 48 patients (mean ± standard deviation, age: 65 ± 14 years, 65% males) with paroxysmal AF who didn’t have structural heart disease, heart failure, or stroke. P wave dispersion on 12-lead ECG and left atrial dimension on echocardiography were also measured to evaluate structural and electrical properties. Over 11 years follow up, 15 patients (31.3%) transited to permanent AF, and 12 (25%) had cardio/cerebrovascular events. SNS abnormality (defines as H/M ratio <2.7) was a powerful predictor of vascular events (50% in 9 of 18 patients with SNS abnormality vs 10% in 3 of 30 patients without those, p=0.0008). After adjustment for potential confounding variables such as age, gender, P wave dispersion, left atrial dimension, transit to permanent AF, and medications, SNS abnormality remained predictive of vascular events with hazard ratio of 6.9 [95% confidence interval, 1.9 to 25.7 (p=0.004)].
Conclusion: SNS abnormality is predictive of mortality in patients with paroxysmal AF who did not have conventional risk.