April 16th Question.

Abstract

See Answer to April 9th Following Question A 60-year-old man with prior multiple endocardial catheter ablation procedures for atrial fibrillation and atrial flutters including pulmonary vein isolation, left atrial roof line, and lateral mitral isthmus line was brought to the electrophysiology laboratory for recurrent left atrial flutter. The left pulmonary veins were found to be isolated, but the right pulmonary veins were reconnected. The clinical atrial flutter was inducible, and its left atrial electroanatomic point-by-point activation map is shown in Figure 1 in the left anterior oblique and right anterior oblique views. Entrainment from the left atrial posterior wall and left atrial roof in between the left and right superior pulmonary veins shows demonstrably longer postpacing intervals than tachycardia cycle length. Entrainment maneuvers from the endocardial lateral mitral isthmus (3-o’clock mitral isthmus) and from the proximal coronary sinus electrodes (approximately at 6:30 mitral annulus) are shown in Figure 2. Which of the following statements is the most appropriate next step? Figure 1. Left atrial electroanatomic activation map of the clinical atrial flutter. …