Volume 9, Issue 10 pp. 1026-1035

New Evidence that AV Node Slow Pathway Conduction Directly Influences Fast Pathway Function

J. CHRISTOPH GELLER M.D.

J. CHRISTOPH GELLER M.D.

Division of Cardiology, University Hospitals of Cleveland, and the Cardiac Bioelectricity Research and Training Center, Case Western Reserve University Medical School, Cleveland, Ohio

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LEE A. BIBLO M.D.

LEE A. BIBLO M.D.

Division of Cardiology, University Hospitals of Cleveland, and the Cardiac Bioelectricity Research and Training Center, Case Western Reserve University Medical School, Cleveland, Ohio

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MARK D. CARLSON M.D.

Corresponding Author

MARK D. CARLSON M.D.

Division of Cardiology, University Hospitals of Cleveland, and the Cardiac Bioelectricity Research and Training Center, Case Western Reserve University Medical School, Cleveland, Ohio

Mark D. Carlson, M.D., Division of Cardiology, University Hospital 11100 Euclid Avenue, Cleveland, OH 44106. Fax: 216-844-8216.Search for more papers by this author
First published: 20 April 2007
Citations: 17

Abstract

Interaction Between the Slow and Fast Pathway. Introduction: Shortening of the AV node fast pathway effective refractory period (ERP) following successful slow pathway ablation may be a nonspecific effect of energy application at the AV junction or may be due to elimination of a direct effect of slow pathway conduction on the fast pathway.

Methods and Results: Twenty-six consecutive patients (20 women and 6 men; mean age 45 ± 3 years) with typical AV nodal reentrant tachycardia who underwent successful slow pathway ablation (defined as complete elimination of dual AV node physiology) were studied. The fast pathway ERP (at a drive train cycle length of 600 msec) was determined prior to ablation (baseline) and following unsuccessful and successful ablation attempts. Successful slow pathway ablation shortened the fast pathway ERP significantly (317 ± 9 msec; P < 0.001) compared to baseline (386 ± 12 msec), whereas unsuccessful ablations bad no effect (376 ± 11 msec). Sinus cycle length, the AH interval, and blood pressure were unchanged following successful ablation. Shortening of the fast pathway ERP did not correlate with the number of energy applications or with two measures of the proximity between the slow and the fast pathway.

Conclusion: These results support the hypothesis that shortening of the fast pathway ERP following slow pathway ablation is due to elimination of a direct effect of slow pathway conduction on fast pathway function rather than a nonspecific effect of repeated energy delivery at the AV junction.

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