Faculty Collaboration Database

Modulation of atrial repolarization by site of pacing in the isolated rabbit heart. Circulation 1996 Sep 15;94(6):1465-70

Date

09/15/1996

Pubmed ID

8823007

DOI

10.1161/01.cir.94.6.1465

Abstract

BACKGROUND: Single-site or multisite atrial pacing may reduce the incidence of atrial fibrillation in humans. The therapeutic mechanisms may include synchronization of atrial repolarization (repolarization "memory") and/or decreased dispersion of atrial repolarization. These responses have not been well documented in intact atria.

METHODS AND RESULTS: Monophasic action potential recordings were made from six atrial epicardial sites in 39 isolated perfused rabbit heart preparations during 3 hours of continuous right atrial, left atrial, or biatrial pacing. Action potential recordings obtained at times 0, 45, 90, 135, and 180 minutes were computer analyzed for activation time (AT) and 90% action potential duration (APD) at each site. No consistent relationship could be demonstrated between APD and AT at any time during atrial pacing (all P > .05). On average, left atrial APDs were longer than right atrial APDs by up to 6.3 ms at all times, regardless of the site of pacing (P < or = .05). At all times, dispersion of atrial repolarization was minimized by left atrial pacing compared with right atrial pacing (21.6 +/- 9.1 versus 32.4 +/- 15.1 ms, respectively, at time 0; P < .05). Biatrial pacing provided no further reduction in dispersion of repolarization compared with left atrial pacing (all P > .05).

CONCLUSIONS: No relationship can be demonstrated between atrial AT and APD in the isolated rabbit heart preparation. This differs from ventricular repolarization "memory," which is demonstrable under the same conditions. Left atrial APD is, on average, longer than right atrial APD, suggesting spatial heterogeneity in repolarization. Dispersion of atrial repolarization is minimized by left atrial pacing in this preparation with no further advantage to biatrial pacing.

Author List

Wood MA, Mangano RA, Schieken RM, Baumgarten CM, Simpson PM, Ellenbogen KA

Author

Pippa M. Simpson PhD Adjunct Professor in the Pediatrics department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Action Potentials
Animals
Atrial Function
Cardiac Pacing, Artificial
Electrophysiology
Female
Heart
In Vitro Techniques
Male
Rabbits
Reaction Time