Electrophysiological Features of Atrial Tachyarrhythmias After the Creation of a Left Atrial Roof Line During Catheter Ablation of Atrial Fibrillation

Abstract

SummaryLeft atrial roof line (LARL) can prevent the perpetuation of atrial fibrillation (AF) by delineation of the arrhythmogenic substrate, but it may be associated with an increased incidence of atrial tachycardia (AT). This study was performed to evaluate the characteristics and clinical implications of inducible AT after LARL.A total of 139 consecutive patients with AF who underwent catheter ablation were prospectively enrolled in this study. LARL was required to prevent the perpetuation of AF in 98 of 139 patients (71%). LARL significantly reduced the incidence of inducible AF (before versus after: 100% versus 44%, respectively, P < 0.01), whereas it significantly increased the incidence of AT (18% versus 63%, P < 0.01). ATs were observed after LARL in 62 of 98 patients (63%), and these circuits were determined in 99 of 112 stable ATs (88%), including tricuspid isthmus-dependent (n = 35), mitral annulus (n = 22), septal (n = 15), surrounding right pulmonary veins (PVs) (n = 12), coronary sinus (CS) ostium (n = 4), upper loop (n = 4), surrounding left PVs (n = 4), and LA anterior wall (n = 3). Catheter ablation (CA) successfully terminated 111 of 122 stable ATs (91%) during CA. The occurrence of AT after CA was significantly higher in patients with than in those without residual AT (26% versus 2%, P < 0.05).Induced AT with a stable circuit after LARL creation could be mapped, and delineation of the induced AT may lead to a favorable outcome. An additional left atrial roof line (LARL) after pulmonary vein (PV) isolation prevents AF perpetuation by delineating the arrhythmogenic substrate with favorable clinical results, although it may be associated with an increased incidence of AT.6) In particular, AT with a macro-reentrant mechanism may be highly inducible after LARL creation.However, the characteristics of the AT have not been fully investigated after complete electrical PV isolation and creation of a complete electrical LARL in patients with AF. In this study, we evaluated the influence of LARL after PV isolation on the inducibility of atrial tachyarrhythmias (AF and ATs), and then assessed the electrical characteristics of the inducible ATs before and after LARL creation. MethodsStudy population: The study population consisted of 139 consecutive patients with drug-refractory episodes of AF who underwent initial radiofrequency CA (Table I). The mean age of the patients was 62 years, 82 (57%) were male, and 41 (29%) had persistent AF lasting more than 7 days (long-standing AF more than 6 months; 15 (11%)). Patients were considered for ablation based on the presence of symptomatic AF resistant to ≥ 1 antiarrhythmic drug. Cardiac structural findings assessed by ultracardiography are shown in Table II. No specific exclusion criteria were used. All antiarrhythmic agents were generally discontinued for at least 3 days before CA. Amiodarone was withdrawn at least 2 months before the procedure. All patients provided written informed consent for the electrophysiological study. This study was approved by our insti...