Retrograde access of the left atrium for catheter ablation using robotic magnetic navigation in atrial fibrillation: a case series

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation for which the left atrium (LA) is usually accessed by the antegrade femoral venous route and transseptal puncture. However, in rare cases, alternative routes must be used to overcome anatomical challenges. A retrograde approach via the femoral artery and by subsequently passing the aortic and mitral valve is virtually impossible using conventional catheters. PURPOSE: To investigate the feasibility of a retrograde approach for AF ablation by robotic magnetic navigation (RMN) using floppy radiofrequency ablation catheters. METHODS: Between June 2014 and December 2021, a total of 6 consecutive patients underwent a total of 8 ablation procedures for AF by retrograde approach using a RMN at tour center. A magnetic catheter was introduced through the right femoral artery and manually advanced retrogradely to the aortic arch. Thereafter, it was further advanced to the LA using RMN by switching the magnets to navigation mode, passing through both aortic and mitral valve (Figure 1). Circumferential PVI was performed by antral point-by-point radiofrequency ablation and additional atrial lines were targeted when deemed necessary. Bidirectional conduction block was proven by loss of pulmonary vein potentials on the ablation catheter which automatically moved in a radial manner collecting 16 mapping points. RESULTS: The patient group (Figure 2) consisted of 4 females and 2 males with a mean age of 58,0±10,8years. 4 patients (67%) presented with persistent AF. The mean time between diagnosis and catheter ablation was 5,3±3,5 years. 2 patients (33%) had an acquired mechanical obstruction of the conventional transseptal route. The other 4 patients (67%) had an anatomical abnormality precluding conventional access to the LA. These 4 patients all underwent an unsuccessful ablation attempt via conventional approach elsewhere, before referral to our center. Patients 3 and 4 also underwent an epicardial ablation for AF respectively 1,3 and 6,2 years before catheter ablation using RMN. Patient 3 also underwent a failed attempt on manual catheter ablation using the retrograde route in another center. AF catheter ablation via retrograde access using RMN was possible in all patients and no complications occurred. The mean follow-up was 3,4±3,3 years. CONCLUSION: Our findings indicate that a retrograde transaortic approach for catheter ablation in AF using magnetic navigation system and electroanatomical mapping is technically feasible and safe in patients with anatomical challenges precluding the use of a conventional antegrade transseptal approach. This technique may serve as an indispensable component of the management of this subgroup of patients in experienced centers. [Figure: see text] [Figure: see text]