Tachycardia after Cox maze
BIRMINGHAM, ALABAMA. The development of right or left atrial flutter/tachycardia after an otherwise successful PVI (pulmonary vein isolation) procedure is not uncommon. Most of these arrhythmias disappear on their own, but some persist and require a follow-up ablation. Surgeons at the University of Alabama now report that post-procedural tachycardias are also fairly common after Cox III maze procedures. Their study included 143 patients who had undergone the procedure during the period 1996 to 2005.

All patients were checked for arrhythmias at 2 and 8 weeks postoperatively; those experiencing palpitations at the 8-week check-up were monitored intensively with Holter monitors or event recorders and, if the tachyarrhythmia persisted, they underwent an electrophysiologic study and catheter ablation. A total of 22 patients (15%) were found to have developed a tachycardia that persisted for more than 8 weeks. Another 10 (7%) developed atrial fibrillation that was treated with medication. The electrophysiologic study of the 22 patients showed the presence of a total of 25 arrhythmias – 15 in the right atrium and 10 in the left atrium. The right atrial arrhythmias were evenly divided between the common counterclockwise right atrial flutter and macroreentrant right atrial arrhythmias that did not involve the cavotricuspid isthmus. Three of the left atrial tachycardias involved reentry around the mitral valve annulus, and the remaining 7 were mapped to the roof of the left atrium. It is of interest that the lesions around the mitral valve annulus were created with cryoablation. All post-operative flutter/tachycardias were successfully treated with standard catheter ablation and the patients have now been arrhythmia-free for over 3 years.

The Alabama surgeons conclude that the occurrence of post-operative flutter/tachycardia after a maze procedure is related to gaps in lesions lines either in the line itself or at the end of a line where it abuts an anatomic boundary.

McElderry, HT, et al. Proarrhythmic aspects of atrial fibrillation surgery. Circulation, Vol. 117, January 15, 2008, pp. 155-62

Editor's comment: It would appear that tachycardia/flutter may occur fairly often (10-30%) following both Cox maze procedures and PVIs. Fortunately, most of these arrhythmias disappear on their own, but some may require follow-up ablations which are usually successful.