TOKYO, JAPAN. Between 20 and 50% of atrial fibrillation (AF) patients undergoing a pulmonary vein isolation (PVI) procedure requires one or more follow-up procedures in order to achieve the goal of remaining in normal sinus rhythm long-term without the use of antiarrhythmics. AF recurrence is almost always due to electrical reconnection between the left atrium and the once isolated pulmonary veins. Japanese researchers have found that injecting an isoproterenol solution and ATP (adenosine-5�-triphospate) 20 minutes after completion of the PVI will reveal dormant gaps in the lesion rings encircling the pulmonary veins. Re-ablating these gaps can markedly improve long-term success rates, especially for paroxysmal afibbers.

Now the same group of researchers report that medium-term success rates for single ablations involving paroxysmal afibbers can be improved to 92% by injecting the isoproterenol/ATP solution 30, 60 and 90 minutes after first achieving complete electrical isolation between the pulmonary veins and the left atrium. Their study involved 75 paroxysmal afibbers (92% men, average age 55 years, average duration of AF 4.5 years). Thirty-five patients had heart disease and 20 had hypertension.

All patients underwent a PVI procedure using the double Lasso technique with accompanying CARTO electroanatomical mapping. Thirty minutes after a bidirectional conduction block had been established between the left atrium and the pulmonary veins, the double Lasso catheters were used to check if gaps had developed in the lesions rings. Seventy-five gaps were found in 37 patients. These gaps were successfully re-ablated whereupon the isoproterenol/ATP solution was injected and the search for gaps repeated. This time 76 gaps were found and successfully re-ablated. The above procedure was repeated 60 minutes after the completion of the initial PVI procedure. This time 64 new gaps were found and re-ablated. After injection of the isoproterenol/ATP solution, another 36 gaps appeared and were re-ablated. Finally, 90 minutes after the completion of the initial PVI, another 8 gaps were found and successfully re-ablated. Total average procedure time was about 3 hours including the 90-minute post-procedure wait time.

At the mean follow-up of one year (370 days) only 6 patients (8%) had experienced recurrence of AF resulting in a medium-term success rate of 92%.

Yamane, T, Yoshimura, M, et al. Repeated provocation of time- and ATP-induced early pulmonary vein reconnections after pulmonary vein isolation: eliminating paroxysmal atrial fibrillation in a single procedure. Circulation: Arrhythmias and Electrophysiology, August 13, 2011 [Epub ahead of print]

Editor�s comment: A medium-term, complete success rate (no AF, no antiarrhythmics) of 92% for a single ablation is astonishing and would appear to be readily achievable for paroxysmal afibbers by using a combination of wait time and isoproterenol/ATP injection to reveal gaps that develop in initially intact lesion rings over a period of 60 to 90 minutes after completion of the PVI procedure.