ANN ARBOR, MICHIGAN. Left atrial flutter and supraventricular tachycardia are not uncommon complications of otherwise successful pulmonary vein isolations (PVIs). The incidence of these tachycardias is highly dependent on the protocol used in the ablation procedure. Thus, about 3% of patients treated with the Haissaguerre method (segmental pulmonary vein isolation) can expect to develop a left atrial tachycardia (LAT). In contrast, 20-30% of patients undergoing a circumferential anatomical pulmonary vein isolation (Pappone method) with widely encircling PV lines plus mitral and roof lines may develop LAT.

Electrophysiologists at the University of Michigan report on their investigation of 78 patients who underwent an ablation for LAT after having undergone a circumferential anatomical PVI using the 3-dimensional CARTO mapping system. The researchers mapped a total of 155 LATs and found that 88% were the re-entry type, while 12% were of focal origin. They also noted that 96% of the re-entrant LATs were associated with gaps in ablation lines created during the original PVI. Repeated catheter ablations were successful in eliminating the LATs in 85% of the 78 patients with the most common ablation targets being the mitral isthmus, the left atrial roof, and the septum separating the right and left atrium.

At the 13-month follow-up 77% of the 78 patients were free of afib and LATs without the use of antiarrhythmics. The Michigan EPs conclude that it should be possible to reduce the incidence of LATs by ensuring complete isolation of the pulmonary veins, limiting the number of linear lesions, and ensuring the absence of gaps.

Chae, S, et al. Atrial tachycardia after circumferential pulmonary vein ablation of atrial fibrillation. Journal of the American College of Cardiology, Vol. 50, No. 18, October 30, 2007, pp. 1781-87
Daubert, JP. Iatrogenic left atrial tachycardias. Journal of the American College of Cardiology, Vol. 50, No. 18, October 30, 2007, pp. 1788-90

Editor�s comment: The �revelation� that 20-30% of patients undergoing a circumferential PVI may develop a post-procedure left atrial tachycardia (flutter or SVT) is indeed discouraging and again emphasizes the need of carefully considering one�s options and choosing a highly skilled EP for the procedure. NOTE: Both Dr. Natale and Profs. Haissaguerre and Jais use the segmental procedure, which is associated with the lowest incidence of LATs.