Electrophysiological characteristics of localized reentrant atrial tachycardia occurring after catheter ablation of long-lasting persistent atrial fibrillation.

From the Cardiovascular Center, Yokosuka Kyousai Hospital, Yonegahama-dori 1-16,Yokosuka, Kanagawa, Japan.
Journal of Cardiovascular Electrophysiology (Impact Factor: 3.48). 01/2009; 20(6):623-9. DOI: 10.1111/j.1540-8167.2008.01410.x
Source: PubMed

ABSTRACT Mapping of recurrent atrial tachycardia (AT) after extensive ablation for long-lasting persistent atrial fibrillation (AF) is complex. We sought to describe the electrophysiological characteristics of localized reentry occurring after ablation of long-lasting persistent AF.
Out of 70 patients undergoing catheter ablation of long-lasting persistent AF, 9 patients (13%, 55 +/- 8 years, 8 males) in whom localized reentry was demonstrated in a repeat ablation were studied. Localized reentry was defined as reentry in which the circuit was localized to a small area and did not have a central obstacle. The mechanism of AT was determined by electroanatomical and entrainment mapping.
Nine localized reentries with cycle length of 243 +/- 41 ms were mapped in 9 patients. The location of AT was the left atrial appendage in 4 patients, anterior left atrium in 2, left septum in 2, and mitral isthmus in 1. In all ATs, a critical isthmus of <10 mm in width was identified in the vicinity of the prior linear lesions or ostia of isolated pulmonary veins. Ablation of the critical isthmus, which was characterized by continuous low-voltage activity (median voltage: 0.15 mV, mean duration: 117 +/- 31 ms), terminated AT and rendered it noninducible. Additionally, ablation was performed for all of inducible ATs. At 11 +/- 7 months after the procedure, 8 of 9 patients (89%) were free from any arrhythmias.
After ablation of long-lasting persistent AF, localized reentry may arise from a site in the vicinity of the prior ablation lesions. Ablation of the critical isthmus eliminates the arrhythmia.

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