Isolated Atrial Fibrillation, Inflammation and Efficacy of Radiofrequency Ablation: Preliminary Insights Based on a Single-Center Endomyocardial Biopsy Study.

The aim of the study was to evaluate the inflammatory changes in the myocardium, based on endomyocardial biopsy (EMB) data in patients undergoing radiofrequency ablation (RFA) for idiopathic atrial fibrillation (AF). A total of 67 patients with idiopathic AF were enrolled in the study. Patients underwent the intracardiac examination, RFA of AF, and EMB with histological and immunohistochemical studies. The catheter-treatment effectiveness, and occurrence of early and late recurrences of atrial tachyarrhythmias, were assessed depending on the identified histological changes. Nine patients (13.4%) did not have any histological changes in the myocardium according to EMB. Fibrotic changes were detected in 26 cases (38.8%). Inflammatory changes according to the Dallas criteria were observed in 32 patients (47.8%). The follow-up period for patients averaged 19.3 ± 3.7 months. The effectiveness rates of primary RFA were 88.9% in patients with the intact myocardium, 46.2% in patients with fibrotic changes of varying severity, and 34.4% in patients with the presence of criteria for myocarditis. No early recurrence of arrhythmias was observed in patients with unchanged myocardia. The presence of inflammatory and fibrotic changes in the myocardium increased the rates of early and late arrhythmia recurrences and accordingly halved the effectiveness RFA of AF.

Biatrial tachycardia following linear anterior wall ablation for the perimitral reentry: incidence and electrophysiological evaluations.

INTRODUCTION: A left atrial (LA) anterior ablation line (AnL), connecting the mitral annulus and right pulmonary veins or a roof line, has been suggested as an alternative to mitral isthmus (MI) ablation for perimitral flutter (PMF). Theoretically, the AnL can exclude the LA septal wall from the reentrant circle, and lead to involvement of the right atrium (RA) in a tachycardia (AT) mechanism. METHODS AND RESULTS: Among 807 patients undergoing atrial fibrillation ablation, PMF was diagnosed in 28 subjects, and AnL was performed in 13, and MI ablation in 15 cases. In 4 (31%) patients, AnL resulted in abrupt AT cycle length prolongation, which was associated with the development of a clockwise biatrial tachycardia (bi-AT). The bi-AT propagated along the lateral and posterior mitral annulus, entered the RA via the coronary sinus, and after activating the RA septum reentered the LA over the Bachmann's bundle. The bi-AT was terminated by ablation in Bachmann's bundle insertion areas in the RA or LA. No bi-AT was documented in the MI group. One patient in the AnL group died of stroke in 10 days following the procedure. Anatomic evaluation showed that at the level of the AnL the RA anteroseptal area was separated from the LA by the aortic root, and was free from ablation damage. CONCLUSION: A bi-AT can develop when an AnL is created for PMF termination. Biatrial entrainment mapping facilitates diagnosis. Termination of the bi-AT is feasible when ablated from either RA or LA.