Learning curve in circular multipolar phased radiofrequency ablation of atrial fibrillation

AbstractBackground: Although atrial fibrillation (AF) ablation is considered a technically challengingprocedure, studies on the learning curve of different pulmonary vein isolation (PVI)techniques are limited. We investigated the time-dependent changes in procedural parameters,complication rates, and in the 1-year clinical outcome during our initial experience with circularmultipolar phased radiofrequency (RF) ablation.Methods and results: The first 132 consecutive patients (40 female; age: 56.6 ± 10.4 years)who underwent PVI with phased RF ablation for paroxysmal or persistent AF at our centerwere included in the study. Procedural parameters and atrial arrhythmia-free survival werecompared in the first, second and third group of 44 successive patients. All pulmonary veinswere successfully isolated in 44 (100%), 41 (93.8%) and 42 (95.5%) patients in Tierce 1,2 and 3, respectively (p = 0.233). The number of RF applications (per vein) required for isolationand fluoroscopy times demonstrated a significant decrease with experience, and a trendtowards lower procedure times in Tierces 2 and 3 was also observed. Atrial arrhythmia-freesurvival rates at 12 months postablation were 68.18%, 75%, and 70.75% in Tierce 1, Tierce 2and Tierce 3, respectively (p = 0.772). Pericardial tamponade requiring percutaneous subxiphoiddrainage occurred in 1 patient (Tierce 3) as the only significant procedural complication.Conclusions: A learning curve effect was demonstrated in fluoroscopy times and in thenumber of RF applications but not in the acute success and in the long-term arrhythmia-freesurvival with circular multipolar RF ablations. (Cardiol J 2015; 22, 3: 260–266

Uninterrupted Dabigatran Administration Provides Greater Inhibition against Intracardiac Activation of Hemostasis as Compared to Vitamin K Antagonists during Cryoballoon Catheter Ablation of Atrial Fibrillation

Background. Cerebral thromboembolism is a rare but feared complication of transcatheter ablation in patients with atrial fibrillation (AF). Here, we aimed to test which pre-procedural anticoagulation strategy results in less intracardiac activation of hemostasis during ablation. Patients and methods. In this observational study, 54 paroxysmal / persistent AF patients undergoing cryoballoon ablation were grouped according to their periprocedural anticoagulation strategy: no anticoagulation (oral anticoagulation (OAC) free; n = 24), uninterrupted vitamin K antagonists (VKA) ( n = 11), uninterrupted dabigatran ( n = 17). Blood was drawn from the left atrium before and immediately after the ablation procedure. Cryoablations were performed according to standard protocols, during which heparin was administered. Heparin-insensitive markers of hemostasis and endothelial damage were tested from intracardiac samples: D-dimer, quantitative fibrin monomer (FM), plasmin-antiplasmin complex (PAP), von Willebrand factor (VWF) antigen, chromogenic factor VIII (FVIII) activity. Results. D-dimer increased significantly in all groups post-ablation, with lowest levels in the dabigatran group (median [interquartile range]: 0.27 [0.36] vs. 1.09 [1.30] and 0.74 [0.26] mg / L in OAC free and uninterrupted VKA groups, respectively, p < 0.001 ). PAP levels were parallel to this observation. Post-ablation FM levels were elevated in OAC free ( 26.34 [30.04] mg / L ) and VKA groups (10.12 [16.01] mg / L), but remained below cut-o in all patients on dabigatran ( 3.98 [2.0] mg / L; p < 0.001). VWF antigen and FVIII activity increased similarly post-ablation in all groups, suggesting comparable procedure-related endothelial damage. Conclusion. Dabigatran provides greater inhibition against intracardiac activation of hemostasis as compared to VKAs during cryoballoon catheter ablation.L