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474 DOES LEFT ATRIAL SCARRING DETERMINE SUCCESS IN PATIENTS UNDERGOING PULMONARY VEIN ISOLATION FOR ATRIAL FIBRILLATION? S Divakara Menon, A Baranchuk, G Nair, J Healey, S Connolly, C Morillo Atrial scarring as demonstrated by regions of low voltages has been demonstrated in patients with atrial arrhythmias especially atrial fibrillation (AF). These changes could result in initiation and perpetuation of AF. Left atrial (LA) scarring has been reported as a surrogate marker of treatment failure in patients undergoing pulmonary vein isolation for AF.
Hamilton, Ontario
AIM OF THE STUDY: 1) To retrospectively evaluate the extent of LA scarring in patients that underwent pulmonary venous isolation for AF and; 2) To assess the clinical characteristics of patients with scarring and the implication of scarring to the short and intermediate term outcome of the ablative therapy for AF.
METHODS: 30 patients who underwent pulmonary vein isolation using an electro anatomic mapping system CARTO were included. Mapping of the LA was performed using a fill threshold of 10. Areas with a bipolar voltage of <0.5 mv were designated as scar. Using the CARTO software, the area of the scarred atrial myocardium were measured and expressed as a percentage of atrial area. The baseline clinical characteristics and outcome of the procedure were evaluated in these patients.
RESULTS: 30 patients, 24 without recurrences and 6 with recurrence requiring re do procedures were included. 3 patients were in persistent AF. Patients with persistent AF had significantly larger percentage scar area compared to paroxysmal AF. Median value of scar area percentage for paroxysmal AF 19.00 (inter quartile interval 7.3 to 25.00) compared to 43.71 (Q1-Q3=31.45-48.83) in persistent AF; P =0.0070. Patients with a procedural failure and recurrence had larger baseline scar area percentages (median 31.23 Q1-Q3 -28.63 to 44.99) compared to patients without (median 15.54 , Q1-Q3 7.15-20.67); P =0.0008.
CONCLUSION: LA scarring was more common in patients with permanent AF and it was related with the success rate of pulmonary venous isolation for AF. Patients with procedural failure and recurrence of the arrhythmia had significantly larger scar in the LA prior to ablation. A larger scar area may be an indicator of recurrence of AF after pulmonary vein isolation.
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