To the Editor- The proper usage of electroanatomic mapping-guided cardioneuroablation.

We read with great interest the case report of cardioneuroablation in ictal asystole by Antolic and colleagues. They tried to ablate ganglionated plexi (GPs) by targeting fractionated electrograms (EGMs) in the anatomic areas where GPs for sinus and atrioventricular node innervation are located. The usage of fractionated EGMs for cardioneuroablation was first defined by our group.2, 3 In our protocol, bipolar endocardial atrial EGMs were evaluated for amplitude and number of deflections at special filter settings and sweep speed. All EGMs were divided into the following subgroups: normal, low-amplitude fractionated EGM (LAFE), and high-amplitude fractionated EGM (HAFE). Then, the sites demonstrating HAFE or LAFE pattern in a region that is consistent with probable localization of GPs were tagged as ablation targets in both atria. Other sites demonstrating LAFE pattern were accepted as scar tissue and excluded from the assessment.

In the present work, the authors should have defined why all sites demonstrating fractionated pattern were not targeted, because it is well known that superior and inferior left atrial GPs are located between the left pulmonary veins (PVs) and the left atrial appendage and within the fat pad below the left inferior PV, respectively. In our research, we demonstrated that both superior and inferior left atrial GPs might be detected by using fractionated EGMs. Although the majority of the fractionated EGMs were detected at the insertion of the right PVs and at the superior vena cava insertions or surrounding the coronary sinus ostium in the left and right atria, respectively, the number of fractional EGMs was higher than that found in the interatrial septum. The main problem for the cardioneuroablation procedure is to localize GPs. Our new electroanatomic mapping–guided strategy may be used to define GP sites by using conventional electrophysiological equipment to achieve complete vagal denervation.