Epicardial maps of atrial fibrillation after linear ablation lesions

Abstract

Introduction: The purpose of this study was to investigate the mechanisms by which atrial linear ablation lesions eliminate atrial fibrillation (AF).

Methods and results: With an array of 112 unipole, epicardial maps of electrically induced AF in 6 dogs (acute group), self-sustained AF in 6 dogs (chronic group), and sinus rhythm and atrial pacing in 3 dogs (control group) were analyzed before and after creating linear radiofrequency ablation lesions in both atria that eliminated the AF. In the acute and chronic groups, activation maps showed multiple wavelets with complex patterns of activation and reentry during AF. Conduction velocity and the number, size, and complexity of wavelets did not change, whereas median fibrillatory cycle length increased with the number of linear lesions. In the control group, refractoriness and conduction velocity were unaffected by the number of lesions.

Conclusions: In these models of AF, linear lesions that eliminate AF increase the cycle length of AF without changing conduction velocity, number of size of wavelets, or complexity of activation patterns.