Author + information
- Received July 20, 1995
- Revision received November 3, 1995
- Accepted December 11, 1995
- Published online April 1, 1996.
- Erica D. Engelstein, MD,
- Kenneth M. Stein, MD,
- Steven M. Markowitz, MD and
- Bruce B. Lerman, MD, FACC*
- ↵*Address for correspondence: Dr. Bruce B. Lerman, Division of Cardiology, The New York Hospital-Cornell Medical Center, 525 East 68th Street, Starr-4, New York, New York 10021.
Objectives. This study sought to present evidence that fast atrioventricular (AV) node pathways with posterior exit sites may participate in typical AV node reentry.
Background. Catheter ablation of the slow AV node pathway in the posteroseptal right atrium is the preferred therapeutic approach in patients with AV node reentrant tachycardia. Despite the success achieved with this approach, electrophysiologic changes consistent with fast pathway ablation are occasionally observed. One potential explanation is the presence of an aberrant posterior fast pathway.
Methods. The location of fast and slow AV node pathways was determined by atrial activation mapping along the tricuspid valve annulus during tachycardia and was further confirmed by the effect of radiofrequency catheter ablation.
Results. Seven patients with AV node reentrant tachycardia had evidence of a posterior fast pathway near the coronary sinus os. Abolition of anterograde and retrograde fast pathway conduction followed radiofrequency ablation in the posteroseptal region in six patients. Consistent with fast pathway ablation, the AH interval increased from 70 ± 24 to 195 ± 35 ms (mean ± SD), and tachycardia was no longer inducible. Selective slow pathway ablation was performed in one other patient with a posterior fast pathway.
Conclusions. Functionally fast AV node pathways may be located in the posteroseptal right atrium, where slow pathway modification is performed. These data delineate the limitations of an anatomically guided slow pathway ablative approach and emphasize the importance of detailed mapping and localization of the retrograde fast pathway exit site before ablation. Failure to recognize the presence of posterior fast AV node pathways may account for sporadic examples of AV block, complicating posteroseptal ablation in patients with AV node reentry.
This study was supported in part by Grant RO1-44747 from the National Institutes of Health, Bethesda, Maryland. Dr. Lerman is an Established Investigator of the American Heart Association, Dallas, Texas.
- Received July 20, 1995.
- Revision received November 3, 1995.
- Accepted December 11, 1995.
- American College of Cardiology