Preserved Left Atrial Epicardial Conduction in Regions of Endocardial “Isolation”
Author + information
- Benedict M. Glover, MD∗ (benedict.glover{at}queensu.ca),
- Kathryn L. Hong, BSc,
- Adrian Baranchuk, MD,
- David Bakker, BSc,
- Sanoj Chacko, MD and
- Gianluigi Bisleri, MD
- ↵∗Address for correspondence:
Dr. Benedict M. Glover, Department of Cardiology, Queen’s University, Kingston General Hospital, 76 Stuart Street, 3rd Floor, Armonstrong Wing, Kingston, Ontario K7L 2V7, Canada.
Despite the fact that catheter ablation is highly successful for paroxysmal atrial fibrillation (AF), some patients require multiple procedures. The success for persistent AF is significantly lower. One of the major limitations of catheter ablation is the difficulty in assessing the extent of lesion transmurality. The lack of transmural lesions means that despite endocardial ablation, electrical conduction may continue to occur on the epicardium and subepicardium. Additionally, it has been shown that asynchronous activation of the endo-epicardial wall may occur during AF (1).
A 50-year-old patient with a history of symptomatic persistent AF for which he previously underwent 3 transcatheter ablations (pulmonary vein [PV] isolation and posterior left atrial [LA] isolation with noncontact force CoolFlex catheter [Abbott, Inc., St. Paul, Minnesota]; last procedure 2014) was referred for consideration of a combined hybrid epicardial and endocardial ablation following a recurrence of AF. High-resolution endocardial mapping of the LA using the EnSite Precision mapping system (Abbott) demonstrated isolation of all 4 PV as well as the posterior wall of the LA (Figure 1).
Epicardial Access, Fluoroscopic Images, and Voltage Maps of the Endocardium and Epicardium of the Posterior Wall of the Left Atrium
Access to the pericardial space was obtained using a right thoracoscopic approach in which a 15 mm Advisor circular mapping catheter (Abbott, Inc., St. Paul, Minnesota) was introduced into the transverse pericardial sinus between the superior vena cava (SVC) and the right superior pulmonary vein (RSPV) (top left). This catheter is shown mapping in the region of the left atrial appendage (Spi Epi) on the bottom left image with a 20 mm spiral catheter on the endocardial surface (SpiEndo) of the left atrium. The endocardial voltage map in the top right shows electrical isolation of the posterior wall and all 4 pulmonary veins while the epicardial map in the bottom right shows electrical activity in the posterior wall as well as the carina between the left superior and inferior pulmonary veins as well as the posterior aspects of the right superior and inferior pulmonary veins. RA = right atrium; RIPV = right inferior pulmonary vein; SpiEndo = Spiral mapping catheter endocardium; SpiEpi = Spiral mapping catheter epicardium.
Epicardial mapping was performed using a right thoracoscopic approach (Figure 1) in which a 15-mm Advisor circular mapping catheter (Abbott) was advanced through both the transverse and oblique pericardial sinuses showing electrical conduction across the posterior wall of the LA as well as electrical connections involving the left superior and inferior PV at the carina and posterior to the right inferior PV. Epicardial ablation was performed with epicardial isolation of all PV and the posterior wall.
This demonstrates the importance of the transmurality of lesions and raises the possibility of continued epicardial conduction particularly in cases requiring repeat procedures and those previously performed with noncontact force catheters or with suboptimal contact force.
Footnotes
Dr. Glover has received consulting fees from Abbott. Dr. Glover is an investigator for CANET (Cardiac Arrhythmia Network of Canada). Dr. Bisleri has received compensation for serving on the speakers bureaus of Articure, Medtronic, Livanova, and Karl Storz. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
All authors attest they are in compliance with human studies committees and animal welfare regulations of the author’s institutions and Food and Drug Administration guidelines, including patient consent where appropriate. For more information, visit the JACC: Clinical Electrophysiology author instructions page.
- Received November 8, 2017.
- Revision received December 11, 2017.
- Accepted December 13, 2017.
- 2018 American College of Cardiology Foundation
