The Modified Anterior Line: An Alternative Linear Lesion in Perimitral Flutter

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Abstract
Ablation of left atrial flutter (LAF) is often limited by the need for technically demanding linear lesions. We evaluated the safety and efficacy of a new modified anterior line (MAL), connecting the anterior/anterolateral mitral annulus with the left superior pulmonary vein for ablation of perimitral flutter. MAL was performed in 65 patients (15 females, age 63.6 +/- 9.8 years) with perimitral flutter using 3D mapping systems (70.8% Carto, 29.2% NavX). Perimitral flutter was either the presenting arrhythmia (73.8%) or an intermediate organized rhythm during atrial fibrillation ablation. Follow-up included repetitive 7-day Holter with 93.8% of patients off antiarrhythmics. MAL was acutely effective in 63/65 patients (96.9%). Termination to sinus rhythm occurred in 36 of 65 patients (55.4%), and in 27 of 65 patients (41.5%) there was a change to another LAF type. Bidirectional block across the MAL was achieved in 56 of 65 patients (86.1%). After 6 months of follow-up, 20 of 41 patients (48.8%) had a LAF recurrence, with 6 patients undergoing a reablation. In all redo patients the MAL was still complete and LAF mechanism was different to the initially targeted. No major complication occurred during the ablation procedures or in the postablation period. The MAL is a safe and effective linear lesion for the treatment of perimitral LAF. Its value compared to more established linear lesions as the mitral isthmus line has to be evaluated in larger studies.