Catheter Ablation -> Atrial Fibrillation & Atrial Flutter: -> Mapping & Imaging D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-182 - Post Operative Atrial Tachycardias After Mitral Valve Surgery : Specificity Of Biatrial Transeptal Lesion (ID 954)


Background: The vertical biatrial trans-septal approach (BTSa) for mitral valve (MV) surgery is associated with a higher incidence of incisional atrial tachycardias (AT).
Objective: We aim to investigate the complexity of BTSa related AT by high resolution mapping system.
Methods: All patients with previous MV surgery via BTSa for MV repair or replacement, who underwent ablation of AT in our institution from January 2017 to September 2019, were enrolled. Patients previously ablated for AF, or with evidence of AF during the procedure were excluded. Detailled AT high-resolution mapping were analysed to define AT circuit and critical isthmus.
Results: We enrolled 49 patients (median age 57±15), with maximum 5 AT per procedure (1.8±1.1). A total of 112 AT were mapped. At baseline, 72% were persistent AT. Cycle length was 314±74 msec. A multiple re-entry circuit was observed in 70% of index AT. We identified 152 critical isthmus (CI, maximum 5 per procedure). Only 28% of our patients had a single CI; CTI was the most frequent one (n=37), counting for 33% AT, while BTS scars altogether for 65% AT. A complete AT circuit was mapped in the RA, the LA and both atria in respectively 49%, 12% and 39% AT. Biatrial and left AT leads to superior procedure, RF and fluoroscopy duration (p<0.05). SR was restored in 95% of patients. At discharge, four patient requiered a pacemaker implantation. Ten patients had a second procedure for AT.
Conclusion: AT occurring after a BTSa have a high prevalence of multiple loop re-entry circuits. Ablation frequently requires a left atrial access. Mapping of both atria should be considered to identify CI and tailored ablation strategy.