Author + information
- Received July 28, 2015
- Revision received September 1, 2015
- Accepted September 3, 2015
- Published online February 1, 2016.
- Samuel H. Baldinger, MD,
- Saurabh Kumar, BSc(Med)/MBBS, PhD,
- Chirag R. Barbhaiya, MD,
- Koichi Nagashima, MD, PhD,
- Laurence M. Epstein, MD,
- Roy John, MD, PhD,
- Usha B. Tedrow, MD, MSc,
- William G. Stevenson, MD and
- Gregory F. Michaud, MD∗ ()
- Cardiac Arrhythmia Center, Cardiovascular Division, Brigham and Women’s Hospital, Boston, Massachusetts
- ↵∗Reprint requests and correspondence:
Dr. Gregory F. Michaud, Cardiovascular Division, The Cardiac Arrhythmia Center, Brigham and Women’s Hospital, 75 Francis Street, Boston, Massachusetts 02115.
Objectives This study sought to assess loss of pulmonary vein (PV) excitability to pacing relative to the development of entrance block and the anatomic completion of the circumferential radiofrequency ablation (RFA) line.
Background During encircling RFA for PV isolation (PVI), entrance block develops before anatomic completion of encirclement (early) in some patients. We hypothesized that early entrance block may be associated with loss of PV excitability to pacing.
Methods In 30 patients undergoing PV isolation (age 61 ± 10 years, 21 men), excitability to pacing was assessed at predefined PV sites when entrance block developed and after completion of the RFA line.
Results Of 60 PV pairs, 37 developed entrance block early, with a gap ≥10 mm in the RFA line. In only 35% of PV pairs in this subgroup, both PV sleeves captured, and all of the capturing PV pairs showed exit block (no conduction from PV to atrium) despite the presence of an excitable gap. In the remaining 23 PV pairs, entrance block did not occur until encircling RFA was anatomically complete. In 83% of these PV pairs, both sleeves captured with exit block (p < 0.001 compared with early block PVs).
Conclusions The majority of PV pairs develops entrance and exit block before complete anatomic encircling by RFA lesions. Early entrance block is frequently associated with loss of PV sleeve excitability, consistent with a spreading wave of injury or edema rather than a permanent conduction barrier. This may help to explain the significant rate of PV conduction recovery associated with the acute endpoints of entrance and exit block.
Dr. Baldinger has received educational grants from the University Hospital of Bern, Switzerland, and the Swiss Foundation for Pacemakers and Electrophysiology. Dr. Epstein is a consultant for BSC, Medtronic, St. Jude Medical, and Spectranetics; and is on the Speakers Bureaus of Medtronic, St. Jude Medical, and Spectranetics. Dr. John receives consulting fees from St. Jude Medical and Biosense Webster; and lecture fees from St. Jude Medical and Boston Scientific. Dr. Tedrow receives consulting fees from St. Jude Medical; and research funding from Boston Scientific and Biosense Webster. Dr. Michaud receives consulting fees from St. Jude Medical; honoraria for speaking/lectures from Boston Scientific, Medtronic, St. Jude Medical, Atricure, and Biosense Webster; and research funding from Boston Scientific and Biosense Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received July 28, 2015.
- Revision received September 1, 2015.
- Accepted September 3, 2015.
- American College of Cardiology Foundation