Zero-Fluoroscopy Cardiac Ablation: Technology Is Moving Forward in Complex Procedures—A Novel Workflow for Atrial Fibrillation

Background and Rationale. A fluoroscopy-based approach to an electrophysiological procedure is widely validated and has been recognized as the gold standard for a long time. The use of fluoroscopy exposes both the healthcare staff and the patient to a non-negligible dose of radiation. To minimize the risks associated with the use of fluoroscopy, it would be reasonable to perform ablation procedures with zero fluoroscopy. This approach is widely used in simple ablation procedures, but not in complex procedures. In atrial fibrillation (AF) ablation procedures, fluoroscopy remains the main technology used, in particular to guide the transseptal puncture. Main results and Implications. We present a workflow to perform a complete zero-fluoroscopy ablation for AF ablation procedures using a 3D electro-anatomical mapping system, intracardiac echocardiography and a novel steerable guiding sheath that can be visualized on the mapping system. We present two cases, one with paroxysmal AF and the other one with persistent AF during which we applied this novel workflow achieving a successful pulmonary vein isolation without complications and complete zero-fluoroscopy exposure.

Do we need imaging support to minimize radiation exposure in cryo-ablation for atrial fibrillation? The VLADIMIR strategy

Introduction and objective Cryoballoon pulmonary vein isolation (CB-VPI) is non-inferior to radiofrequency ablation in patients with atrial fibrillation. Although protocols aiming to reduce radiation exposure have been developed, most of them use intracardiac echocardiography (ICE) or electroanatomic mapping (EAM) systems, which significantly increase procedure costs or may not be widely available. Previous studies aiming at fluoroscopy reduction have been published, achieving median fluoroscopy times around 10 minutes. We developed a novel strategy to achieve Very Low rADIoscopic exposure to Minimize Ionizing Radiation during cryoablation of atrial fibrillation (VLADIMIR) (Table 1). The aim of this study was to assess its impact in acute procedural and clinical outcomes. Methods Consecutive patients undergoing CB-VPI were prospectively enrolled, treated with the VLADIMIR strategy and compared to a retrospective cohort of patients having undergone CB-VPI performed by the same operators with conventional fluoroscopy strategy. Primary end-points were fluoroscopy time and total dose area product (DAP). Secondary end-points were intraprocedural or early post-procedural complications. Results A total of 84 patients were enrolled. 50 patients underwent CB-VPI with conventional fluoroscopy strategy and in 34 patients the Vladimir strategy was applied. Vladimir group had significant lower median fluoroscopy time (2.98 min vs 20.65 min, p<0.001) and significant lower median DAP (4.15 Gy·cm2 vs 34.12 Gy·cm2, p<0.001) as compared with conventional fluoroscopy strategy group. Results from prespecified subgroup analysis between operators (senior vs fellow trainee) were consistent. No significant differences were found between both groups in periprocedural complications (Table 2). Conclusion The Vladimir protocol significantly reduces fluoroscopy time and radiation exposure during CB-VPI without affecting the rate of periprocedural complications. FUNDunding Acknowledgement Type of funding sources: None. Table 1. The VLADIMIR strategy Table 2

Anatomical variants of the cavotricuspid isthmus in patients undergoing catheter ablation for atrial flutter and/or atrial fibrillation

Background We evaluated the differences in the anatomy of the cavotricuspid isthmus (CTI) by assessing image loops provided by intracardiac echocardiography (ICE) in patients who underwent ablation for atrial flutter and/or atrial fibrillation. Purpose CTI is an essential component of the reentrant circle in isthmus–dependent atrial flutter (CTI-AFL) and a target for catheter ablation. In some patients, CTI anatomy may be responsible for a difficult procedure. The aim of this study is to describe in details the anatomical variants of this structure. Methods We included a group of 138 patients, who underwent cardiac ablation for atrial flutter and/or atrial fibrillation between August 2020 and January 2021. Intracardiac echocardiography was employed during the intervention to evaluate the morphology of CTI. Analysis was focused on size, shape, presence of sub-eustachian pouch (excavation more than 5 mm) or presence of prominent Eustachian ridge (ER, embryologic remnant of the valve of the IVC) and mobility of the structure. Results The length of CTI measured during ventricular systole averaged at 38,4mm (min 22,5mm, max 60mm). The most frequent pattern was a flat CTI without sub-eustachian excavation or with excavation less than 5mm (71 patients; 51.4%). A pouch (excavation more than 5mm) was observed in 41 pts (29.7%), where the deepest pouch reached 10,5mm. Prominent ER was present in 58 pts (42%). The remaining 26 of CTIs (18.8%) were classified in the “unclassifiable” category with deviations from common anatomic variants - substantial convexity, pronounced trabeculation of isthmus or double pouch. We observed 14 CTIs (10.1%), where the structure was partially or in full extent detached from the diaphragm, sliding during cardiac contractions. In addition to the described morphology, Chiari's network was observed in 18 pts (13%). In reference to mobility, 53 pts (38.4%) presented with hypermobile CTI with a difference in size of more than 1/3 between the diastole and systole. Moreover, we looked into differences of CTI related to BMI, left atrial volume index (LAVi) and ejection fraction of the left ventricle. A positive correlation was found between LVEF and mobility of CTI. Hypermobile CTI was present in 42.2% of pts with normal LVEF compared to only 18.9% of pts with reduced EF (EF less than 50%). Similar results were observed in pts with non-dilated LA, where hypermobile CTI was present in 51.9% of pts compared to only 35.1% of pts with dilated LA with LAVi >28 ml/m2 (see table below). Conclusions We observed a substantial differences in the anatomy of the CTI, which could play an important role in catheter ablation of this structure. Besides the prominent ER, significant sub-eustachian pouch and hypermobility appear to be variants predisposing to difficult ablation. FUNDunding Acknowledgement Type of funding sources: None. CTI variants related to EFLV, BMI, LAVi CTI detached from the diaphragm