COMMENTARY FROM THE SECTION EDITOR: Left Atrioventricular Groove Mapping Via Placement of a Multipolar Electrode Microcatheter in the Circumflex Coronary Artery

DOI: 10.19102/icrm.2011.020808

George F. Van Hare, MD

Editor-in-Chief

In this month’s journal, McCanta and colleagues describe a difficult procedure in a child with Wolff–Parkinson–White syndrome. The difficulty was partly related to mapping, made more difficult by the cardiac anatomy. In their patient, the coexistence of ostial atresia of the coronary sinus with a persistent left superior vena cava to coronary sinus connection created the mapping challenge. While access to the coronary sinus in this situation was accomplished by cannulating the left superior vena cava via a bridging vein, in this particular patient, the coronary sinus anatomy did not allow the operators to get close enough to the atrioventricular (AV) groove for adequate mapping of the left-sided pathway. Therefore, they employed a 2.5 French microcatheter with 16 electrodes introduced into the circumflex coronary artery.

Most applications of this particular catheter in children have involved the right coronary artery. Its use in that setting gives one a stable recording platform from the entire AV groove, similar to what one gets from a coronary sinus catheter on the left side. The advantages of using the coronary artery on the right side are therefore obvious, as the venous anatomy around the tricuspid annulus does not allow for easy access. However, there are other advantages. First, the epicardial coronary arteries (right and circumflex) run close to the annulus and so electrograms recorded from within the artery give a better estimation of timing at the true electrical annulus. The coronary sinus, in distinction, can be fairly distant from the annulus and therefore may record more of a far-field ventricular electrogram. Standard endocardial mapping of the tricuspid annulus can be difficult when the true AV groove is not obvious, a particular problem in Ebstein’s anomaly. Second, as an epicardial structure, in the rare patient with an epicardial pathway, the coronary artery may allow one to record signals that are superior to those achieved from the endocardium by standard mapping techniques.

In pediatric electrophysiology, we often find ourselves adapting technology designed for common adult indications to the smaller anatomy and congenital anatomic variations found in our pediatric patient population, and this case report is a good example of that principle in practice. The catheter employed was developed for cannulation of epicardial cardiac veins to facilitate mapping of ventricular tachycardia circuits. Unfortunately for those who occasionally use this technology, at the time of writing, the company that manufactured this catheter, Cardima (Fremont, CA) has been sold and production of the catheter has been halted. While not often needed clinically, this technology has been extraordinarily useful in the occasional case and it has been comforting to have this “on the shelf” when needed. We hope that similar technology can be developed and be successful commercially in the larger adult market, so that our patients can continue to have access to this type of mapping.

George F. Van Hare, MD
VanHare@kids.wustl.edu
Director, Pediatric Cardiology
Washington University School of Medicine
St. Louis Children’s Hospital,
St. Louis, MO