Inducibility of Atrial Fibrillation with a Synchronized External Low Energy Shock Post-Pulmonary Vein Isolation Predicts Recurrent Atrial Fibrillation
Dr. Essebag is the recipient of a Clinician Scientist Award from the Canadian Institutes of Health Research (CIHR). Dr. Reynolds is the recipient of grant K23 HL077171 from the NHLBI.
Dr. Reynolds serves on an advisory board for Biosense-Webster Inc.
Dr. Josephson has served as a consultant for Biosense-Webster Inc. and for Medtronic Inc. Dr. Wylie has served as a speaker for Medtronic Inc.
Manuscript received 22 January 2008; Revised manuscript received 31 May 2008; Accepted for publication 3 June 2008.
Abstract
Background: Inducibility of atrial fibrillation (AF) with burst pacing after pulmonary vein (PV) isolation is associated with recurrent AF.
Objective: This study evaluated whether an external 30 Joule (J) shock synchronized to the R wave, during the vulnerable period of atrial repolarization, is able to risk-stratify patients further for AF recurrence after PV isolation.
Methods: One hundred and sixteen consecutive patients underwent PV isolation for AF. Atrial burst pacing was performed after PV isolation. In patients without AF induced by burst pacing, a biphasic external 30 J shock synchronized to the R wave was delivered as a further test for inducible AF. Patients were followed for a mean of 16 months, and recurrent AF was defined as more than 10 sec of AF on ambulatory monitoring.
Results: AF was induced in 19 (16%) of patients with burst pacing. Eighty-one patients who were noninducible with burst pacing had a 30 J shock administered, which induced AF in 16 (20%). In follow-up, 21% of patients who were noninducible with burst pacing or low-energy shock vs 54% who were inducible with either test developed recurrent AF at one year (HR 3.18, P = 0.0004 on multivariate analysis). Among patients who were noninducible with burst pacing, 18% who were noninducible with a low-energy shock vs 60% who were inducible with shock developed recurrent AF at one year (HR = 4.63, P = 0.0006 on multivariate analysis).
Conclusion: Inducibility of AF by a 30 J shock delivered during atrial repolarization after PV isolation may predict AF recurrence. Evaluation of inducibility of AF with burst pacing and a biphasic external synchronized shock after PV isolation may help guide postprocedure management.
