Improved intra-atrial conduction delay after successful ablation for atrial fibrillation by scar homogenization in right atrium

Abstract

Atrial fibrosis in the right atrium (RA) presenting as a low-voltage zone might be the mechanism of atrial fibrillation (AF) and intra-atrial conduction delay. The impact of scar homogenization in RA on intra-atrial conduction delay is unknown. We describe a patient with paroxysmal AF and significant intra-atrial conduction delay with repetitive atrial flutter, triggered from the lateral free wall in the RA between the significant low-voltage zone and slow conduction area after pulmonary vein isolation. Linear ablation along the trabeculated lateral free wall in the RA to homogenize the scar was successfully performed, and the intra-atrial conduction delay improved ultimately. Diseased atrial substrate and extensive atriomyopathy in the right atrium might have resulted in a severe intra-atrial conduction delay (left). Scar homogenization converts low-voltage regions into electrically silent regions completely, which may result in the elimination of zones of non-uniform anisotropic conduction, allowing reduced atrial conduction dispersion, and ultimately, improvement in intra-atrial conduction delay (right).image