The value of cardiac sympathetic nervous system activity in the prognosis of atrial fibrillation radiofrequency ablation
Authors: Varlamova Y.U.V , Zavadovsky K.V , Kisteneva I.V , Sazonova S.I 
Published: November 2020

Abstract

Background
Atrial fibrillation (AF) is one of the widest spread forms of arrhythmia worldwide. To date, radiofrequency catheter ablation (RFCA) of AF is a valuable treatment option. So far there are no clear predictors of the effectiveness of AF ablation. Nowadays, the association of cardiac sympathetic nervous system and the development and maintenance of AF has been showed. However, the association between sympathetic innervation disturbances and AF RFCA effectiveness remains inconclusive.

Purpose
To study the prognostic significance of cardiac sympathetic activity assessed by 123I-MIBG scintigraphy in AF RFCA efficacy.

Methods
The study included 46 patients. All patients were divided into 3 groups: I group - persistent AF (n=20), II group - long-standing persistent AF (LSPAF) (n=16), III group - sinus rhythm patients (n=10). All patients underwent 123I-MIBG and 99mTc-MIBI scintigraphy (planar and SPECT) to evaluate the cardiac sympathetic activity and myocardial perfusion, respectively. Echocardiography was performed in all patients to assess the cardiac contractile function. The effectiveness of interventional treatment was assessed in one year by 24 hour Holter monitoring.

Results
During a median follow-up of 12±6 month, arrhythmia recurrence was observed in 7 (35%) PAF patients and in 8 (50%) LSPAF patients. The univariate regression analysis showed that in patients with PAF the left atrial diameter (LAD), 123I-MIBG washout rate (WR), delayed 123I-MIBG defect score, and 123I-mIBG/99mTc-MIBI mismatch score were predictors of AF recurrence. In this group only the WR was a multivariate predictor of AF recurrence (odds ratios: 1.668, 95% confidence interval: 1.093–2.548, p=0.018). The receiver operator characteristics curve (ROC) analysis indicated the potential diagnostic value of WR to predict recurrence of AF after RFCA in PAF patients with an area under the curve of 0.968 (P&lt;0.05; sensitivity = 100%, specificity = 45%), and an optimum cut-off value of 20.8%. The univariate regression analysis showed that in patients with LSPAF the LAD, WR, delayed 123I-MIBG defect score, rest perfusion defect score and 123I-MIBG/99mTc-MIBI mismatch score were predictors of AF recurrence. According to multivariate analysis only the 123I-MIBG/99mTc-MIBI mismatch score was an independent predictor of AF recurrence in this group of patients (odds ratios: 2.155, 95% confidence interval: 1.192–3.897, p=0.011). ROC analysis gave an optimum cut-off value of 12.5% for the 123I-MIBG/99mTc-MIBI mismatch score with an area under the curve of 0.942 to predict recurrence of AF after RFCA in LSPAF patients (p&lt;0.05, sensitivity = 81%, specificity = 28%).

Conclusions
In AF patients the incidence of arrhythmia recurrence after RFCA is associated with impaired sympathetic nervous activity. The prognosis of AF recurrence in LSPAF patients has a link with rest myocardial perfusion disturbances which may reflect the severer structural change of myocardium.

Funding Acknowledgement
Type of funding source: Foundation. Main funding source(s): Russian Science Foundation