BACKGROUND: An alternative approach to complete isolation of the posterior left atrium (LA), including all pulmonary veins (PVs), for treating atrial fibrillation (AF) is the Box isolation. However, it is sometimes difficult to confirm the conduction block within the linear lesion lines, so in the present study the efficacy of the Box isolation guided by noncontact mapping (NCM) was evaluated. METHODS AND RESULTS: A total of 188 patients, 116 with paroxysmal, 48 with persistent and 24 with longstanding persistent AF, underwent the Box isolation using NCM system. The endpoint was defined as bi-directional conduction block in the posterior LA confirmed by an activation map using NCM during pacing inside and outside of the posterior LA. The induced atrial tachyarrhythmias and non-PV foci were also ablated using NCM. After 12+/-4 months of follow-up, 91% of the patients with paroxysmal AF, 73% of those with persistent AF and 46% with longstanding persistent AF were arrhythmia-free without drugs. CONCLUSIONS: NCM is useful for defining complete Box isolation and detecting the conduction gaps, localizing non-PV foci, and analyzing the mechanism of atrial tachyarrhythmias. NCM-guided Box isolation is a feasible, safe and effective method of treating AF.
BACKGROUND: An alternative approach to complete isolation of the posterior left atrium (LA), including all pulmonary veins (PVs), for treating atrial fibrillation (AF) is the Box isolation. However, it is sometimes difficult to confirm the conduction block within the linear lesion lines, so in the present study the efficacy of the Box isolation guided by noncontact mapping (NCM) was evaluated. METHODS AND RESULTS: A total of 188 patients, 116 with paroxysmal, 48 with persistent and 24 with longstanding persistent AF, underwent the Box isolation using NCM system. The endpoint was defined as bi-directional conduction block in the posterior LA confirmed by an activation map using NCM during pacing inside and outside of the posterior LA. The induced atrial tachyarrhythmias and non-PV foci were also ablated using NCM. After 12+/-4 months of follow-up, 91% of the patients with paroxysmal AF, 73% of those with persistent AF and 46% with longstanding persistent AF were arrhythmia-free without drugs. CONCLUSIONS: NCM is useful for defining complete Box isolation and detecting the conduction gaps, localizing non-PV foci, and analyzing the mechanism of atrial tachyarrhythmias. NCM-guided Box isolation is a feasible, safe and effective method of treating AF.