Abstract 3232: Risk Factor of the Thrombogenicity Related to Left Atrial Catheter Ablation for Atrial Fibrillation
Introduction: Although electrical pulmonary veins antral isolation (PVAI) has been shown to be beneficial in patients with drug-refractory atrial fibrillation (AF), cerebral embolism and stroke are still serious complications of AF ablation. We examined the risk factor of cerebral embolism caused by left atrial and PV catheter ablation, as detected by sensitive cerebral diffusion-weighted magnetic resonance imaging (DW-MRI).
Methods: The subjects of this study were 52 patients (mean age 58 years, 44 males) with AF undergoing only PVAI (n =34), or PVAI+CFEA (continuous fragmented electrogram ablation, n =18). DW-MRI was performed 2 days after the procedures. Adequate heparin was given during the procedure to keep the activated clotting time 200 –250s, with following warfarin administration. Radiofrequency energy was delivered with a power limit of 30 or 35 W.
Results: Postprocedural DW-MRI revealed new small embolic cerebral lesions (bright DW lesions) in 9 of 52 patients in cerebellum (5), frontal lobe (2), white matter (2), and parietal lobe (1). However, clinical neurological exam before and after the procedure was normal in all 9 patients. There was no statistical significance in age, history of AF, echocardiographic parameters, and procedure time between the patients with and without embolic cerebral lesions. The applied direct-current cardioversion during ablation procedure was only significantly associated with the occurrence of silent cerebral thromboembolism (p<0.05). Additional CFEA to the PVAI did not increase the incidence of thrombogenicity. However, in the patients who underwent CFEA, radiofrequency application with a power limit of 35 W (not 30W) was associated with higher prevalence of positive DW-MRI findings (4/7 (max. 35W) vs. 0/11 (max 30W), p<0.05).
Conclusions: Our results demonstrate unexpectedly higher incidence of asymptomatic cerebral embolism related to the left catheter ablation procedures. Radiofrequency application to the LA with higher power limit (35 W) during CFEA and the applied direct-current cardioversion during the ablation procedures were associated with the thrombogenicity of left atrial catheter ablation.