ECG and echocardiographic changes after linear ablation at the superior left atrial septum

Background: Left atrial (LA) linear ablation at the superior septum from the right superior pulmonary vein (PV) to the mitral annulus, the alternative to the mitral isthmus (MI) line between the left inferior PV and mitral annulus, results in significant prolongation of LA activation time. Aim: To assess whether a superoseptal line affects echocardiographic and ECG parameters that are able to demonstrate successful ablation. Methods: Patients (pts) with long lasting (≥ 48hours) paroxysmal, recurrent (i.e. after previous PV isolation) or persistent atrial fibrillation (AF) were randomized to superoseptal or MI line, and sinus rhythm (SR) activation maps of the LA (EnSite NavXTM, SJM), echocardiographic and ECG parameters were compared before and after ablation. Results: 70pts (64 (56-68) years, 19 (27%) female) were enrolled. Bidirectional block was achieved in 29/35 (83%) of those randomized to the superoseptal line. This resulted in a significantly prolonged P wave duration (141 (129,162) vs. 183 (161,201) msec; P 50% of the duration). In addition, a reduction of the A wave and E/A integral was also observed after successful ablation. Whether this translates into negative long term hemodynamic effect needs to be assessed.