Focal activity in atrial fibrillation: state of the art

Abstract

Focal activity is one of the dominant triggers of atrial fibrillation. Its activity is revealed in paroxysmal as well as in persistent patterns of arrhythmia. Starting as a trigger of atrial fibrillation in pulmonary veins, over time with increasing of burden of atrial fibrillation, focal activity is more and more revealed out of pulmonary veins: anterior and posterior left atrial walls, interatrial septum, coronary sinus, ligament of Marshal and right atrium. Diagnostics of focal activity is a challenging clinical task despite implementation of mathematical algorithms of electrogram analysis because of its spatial instability and activation direction of the mapping electrode. All these items are discussed in the article.