Figure Legends
Figure 1 - Extracardiac Vagal Stimulation Methodology: A: The ECVS is performed without direct contact with the vagus nerve through a specific Vagal Stimulator or a Neuro-Stimulator using pulses with an amplitude of 1V/Kg of body weight up to a maximum of 70V with 50microseconds and frequency of 50Hz; B: Schematic of the catheter inside the right or left internal jugular vein; C: Diagram of the anatomy of a section of the cervical region showing the close proximity of the vagus nerve and the internal jugular vein; D: anteroposterior radiological view of the position of the vagal stimulation catheter. The best stimulation site is usually from the lower limit of the orbit to the root of the wisdom tooth.
Figure 2 - ECVS Methodology. In the ECVS Group, the ECVS was used for gradual control of CNA and for the endpoint. A: before CNA, a sinus arrest is observed under ECVS. It is the usual response to ECVS in normal people due to sinus node suppression; B: When ECVS is performed with atrial pacing 10 to 20 ppm above the previous sinus rate before CNA, high-grade AV block is usually observed due to AV node suppression; C:ECVS applied after the CNA, obtaining a total absence of a vagal effect. There is no more sinus arrest, sinus pause, bradycardia or AV block. This was the expected endpoint in this group of patients.
Figure 3 - A: Schematic of endocardial sites usually ablated during CNA. As the GPs are not visible, the sites of interest are assumed to be anatomically close and numbered from 1 to 4. In addition to the GP regions, the most important area for the CNA is the P Point located on the left side of the interatrial septum. In cases of more difficult denervation, additional areas are ablated such as the roof of the coronary sinus, the region of the Marshall’s vein, superior vena cava, anterolateral wall of the right atrium, the Waterston groove and any other area indicated by the fractionation mapping; B: Schematic of the sites of the four main ganglionated plexuses. Site 1: between superior vena cava and aorta; Site 2: antrum of the right pulmonary veins; Site 3: Confluence of the coronary sinus ostium and the inferior vena cava; Site 4: Insertion of the left pulmonary veins.
Figure 4 - A: Kaplan-Meier survival curves showing the free probability of syncope in the ECVS group (CNA controlled with ECVS) and in the NoECVS group (CNA without ECVS); B: Hazard cumulative risk curves for the possibility of recurrence comparing the CNA controlled with ECVS group with the CNA group without ECVS control.
Figure 5 - Fractionation software. In the normal heart, vagal innervation can be indirectly identified through AF-Nests by spectral mapping. Based on this method, we developed the Fractionation software that allows the identification of AF-Nests in the electroanatomical model without the need for spectral analysis. Additionally, innervation can be approached by approximation by using the assumed position of the GPs. However, in many cases, due to anatomical variations, the fractionation map is necessary to complement the anatomical method and obtain complete denervation.