The quest for achieving durable mitral isthmus block: probing the heights of the left lateral ridge

Excerpt

Mitral annular flutter may occur either isolated or after catheter ablation for atrial fibrillation. It is oftentimes refractory to antiarrhythmics but amenable to catheter ablation. Two ablation approaches have been devised, one involving the creation of lesion lines across the mitral isthmus (MI), defined as the region extending between the left inferior pulmonary vein and the mitral annulus, and the second one consisting of lines along the left atrial (LA) anterior wall and connecting the right superior pulmonary vein with the mitral annulus [1]. Each of these strategies presents unique potential advantages and challenges. The MI line is directed along the shortest path between the mitral annulus and the left inferior pulmonary vein, albeit its completion oftentimes requires complementary ablation in the adjacent coronary sinus with the risk of left circumflex artery thermal injury, coronary sinus thrombosis, and pericardial tamponade [1, 2]. The anterior line is performed endocranially only. It is, however, longer than the MI line and may promote delayed activation of the LA appendage, atrio-ventricular electromechanical desynchrony, and possibly increased risk of thromboembolism. [3] …