Techniques, Evaluation, and Consequences of Linear Block at the Left Atrial Roof in Paroxysmal Atrial Fibrillation

Abstract

Background-There are no reports describing the technique, electrophysiological evaluation, and clinical consequences of complete linear block at roofline joining the superior pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF). Methods and Results-Ninety patients with drug-refractory paroxysmal AF undergoing radiofrequency ablation were prospectively randomized into 2 ablation strategies: (1) PV isolation (nϭ45) or (2) PV isolation in combination with linear ablation joining the 2 superior PVs (roofline; nϭ45). In both groups, the cavotricuspid isthmus, fragmented peri-PV-ostial electrograms, and spontaneous non-PV foci were ablated. Roofline ablation was performed at the most cranial part of the left atrium (LA) with complete conduction block demonstrated during LA appendage pacing by the online mapping of continuous double potential and an activation detour propagating around the PVs to activate caudocranially the posterior wall of the LA. The effect of ablation at the LA roof was evaluated by the change in fibrillatory cycle length, termination and noninducibility of AF, and clinical outcome. PV isolation was achieved in all patients with no significant differences in the radiofrequency duration, fluoroscopy, or procedural time between the groups. Roofline ablation required 12Ϯ6 (median 11, range 3 to 25) minutes of radiofrequency energy delivery with a fluoroscopic duration of 7Ϯ2 minutes and was performed in 19Ϯ7 minutes. Complete block was confirmed in 43 patients (96%) and resulted in an activation delay that was shorter circumventing the left than the right PVs during LA appendage pacing (138Ϯ15 versus 146Ϯ25 ms, respectively; Pϭ0.01). Roofline ablation resulted in a significant increase in the fibrillatory cycle length (198Ϯ38 to 217Ϯ44 ms; Pϭ0.0005), termination of arrhythmia in 47% (8/17), and subsequent noninducibility of AF in 59% (10/17) of the patients inducible after PV isolation. However, LA flutter, predominantly perimitral, could be induced in 10 patients (22%) after roofline ablation. At 15Ϯ4 months, 87% of the roofline group and 69% with PV isolation alone are arrhythmia free without antiarrhythmics (Pϭ0.04). Conclusions-This prospective randomized study demonstrates the feasibility of achieving complete linear block at the LA roof. Such ablation resulted in the prolongation of the fibrillatory cycle, termination of AF, and subsequent noninducibility and is associated with an improved clinical outcome compared with PV isolation alone. (Circulation. 2005;112:3688-3696.)

Catheter Ablation of Lone Atrial Fibrillation

“…AF substrate also can be modified by the linear atrial ablation, which imitates the surgical MAZE procedure, in form of the roof line and, eventually, the inferior line on the LA posterior wall, connecting both superior and both inferior PVs. In this way, a complete electrical isolation of the whole LA posterior wall is achieved (so called "posterior box lesion"), as shown in Figure 3 [9,52]. Linear ablation of mitral isthmus between the mitral annulus and the left inferior PV can significantly modify AF substrate [53].…”

Temperature-Controlled Cooled-Tip Radiofrequency Linear Ablation of the Atria Guided by a Realtime Position Management System

“…1,2,18) However, left mitral isthmus ablation, left atrial roof linear ablation, and linear catheter ablation to transect the anterior left atrium were shown to be necessary to maintain sinus rhythm particularly in patients with persistent AF. [19][20][21] Furthermore, in patients with persistent and permanent AF, circumferential PV ablation, combined with linear lesions in the right atrium in addition to left atrial and CS ablation, is reported to be feasible and safe, with a significantly high success rate. 22,23) However, creating transmural linear lesions with a multipolar ablation system or by the pull-back approach is difficult.…”

Predictive risk factors for recurrent atrial fibrillation after modified endoscopic ablation: A 2‐year follow‐up

“…The effectiveness of adding an ablation line at the LA roof has been proven in several studies before. 16,17 Hocini and colleagues 17 reported that ablation along the LA roof resulted in a slowing of the AF process and termination of AF in 47% of patients who were diagnosed with PAF. In our study, in which complete transmurality and continuity were guaranteed by overlapping ablation and the addition of a CLAA ring, the modified endoscopic procedure had a similar success rate in PAF and non-PAF patients.…”