PMC9845552_01
Six months after the first cardioneuroablation. A: Spontaneous atrioventricular block (AVB) during syncope. B: High-degree AVB during carotid sinus massage. C: Carotid sinus massage after atropine without AVB.
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This response was eliminated after 2 mg intravenous atropine infusion with no increase in sinus rate (Figure 1), and a redo CNA procedure was scheduled.
Before and after second cardioneuroablation (CNA): extracardiac vagal stimulation (ECVS) evaluation, atrial fibrillation (AF) nest, anatomical- and fractionation map-guided CNA. A: Initial ECVS response showing transient atrioventricular block (AVB) and absence of sinus rate changes. B: Electroanatomic mapping right anterior oblique (RAO) view of fractionation map location G3 (area related to posterior medial ganglionated plexus) and radiofrequency (RF) lesion set. Red circle = filtered ablation catheter electrogram (300-500 Hz) for atrial fibrillation nest mapping at the G3 location; red dots = RF lesion set. C: ECVS response after biatrial second CNA showing absence of vagally induced asystole or AVB. D: Left vagus ECVS catheter position.
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Biatrial radiofrequency (RF) ablation of the neuro-endomyocardial interface guided by filtered endocardial electrograms (300-500 Hz), anatomical landmarks, and fractionation mapping (EnSite Velocity; Abbott, Chicago, IL) tracking AFN areas related GP4 location on the posterior surface of left superior and left inferior pulmonary veins antrum, and the GP3 location, the posterior medial GP in left and right atrium posterior septal space and coronary sinus roof, using a FlexAbility (Abbott) irrigated catheter (30 W / 43 C / 30-60 s) guided by impedance drop of 10%-15% (Figure 2); nonsignificant changes were observed in electrophysiological parameters (Table 1). AV conduction even under right atrial pacing at 400 ms, achieving complete elimination of the vagal AVN response. At the end of the second CNA, CSM was repeated with no effect on the sinus node and the AVN conduction (Figure 2). Additionally, at this point, atropine test was performed with 2 mg intravenous infusion, reconfirming absence of heart rate increase.
The 24-hour ventricular heart rate pattern and heart rate variability (HRV) in time domain. A: Before cardioneuroablation. B: Six months post second cardioneuroablation. C: Twenty months post second cardioneuroablation.
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Heart rate variability 24-hour Holter recording analysis showed sympathetic predominance, no signs of significant reinnervation (Figure 3), and no symptoms or syncope recurrence.