© 2002 by European Society of Cardiology
Copyright © 2002, European Society of Cardiology
Suppression of atrial fibrillation by multisite and septal pacing in a novel experimental model
University of Heidelberg, Department of Cardiology, Heidelberg, Germany
* Corresponding author. University of Heidelberg/Department of Cardiology, Bergheimer Strasse 58, 69115 Heidelberg, Germany. Tel.: +49-6221-568-855; fax: +49-6221-565-514 ruediger_becker{at}med.uni-heidelberg.de
Objectives: To evaluate the preventive efficacy of multisite and septal atrial pacing in an experimental model. Methods: Sterile right atrial pericarditis was induced in 12 foxhounds to provide an anatomical substrate for atrial fibrillation (AF). As a trigger mechanism, atrial extrasystoles were simulated by constant asynchronous pacing at a cycle length of 1000 ms from randomly selected right or left atrial electrodes, using a biatrial epicardial multielectrode with 128 bipoles. Additionally, a transvenous pacing lead was screwed into the interatrial septum. Four electrodes located in the high and low right (HRA/LRA) and left atrium (HLA/LLA) were selected for preventive multisite stimulation. Constant pacing at a cycle length 30 ms below sinus rate was applied from the following site(s): HRA, septal, HRA+LRA, HRA+LLA, HRA+LRA+LLA and HRA+LRA+HLA+LLA (order randomized). Number and duration of AF episodes were studied during 10 min intervals, separated by 5 min pauses, respectively. To validate the model, the protocol was repeated 10 min after i.v. bolus administration of D,L-sotalol (1 mg/kg body weight). Results: The number of AF episodes decreased with increasing number of pacing sites, reaching statistical significance compared to HRA stimulation for quadruple-site and single-site septal pacing only (P<0.05). Single-site septal was as efficient as quadruple-site pacing in suppressing AF. The duration of AF episodes was not significantly affected by the pacing configuration. D,L-sotalol almost completely suppressed AF irrespective of the pacing configuration used. Conclusions: In this novel experimental model, quadruple-site and septal pacing effectively suppress paroxysmal AF.
KEYWORDS AF, Atrial fibrillation; AT, Activation time; CL, Cycle length; ERP, Effective refractory period; HLA, High left atrium; HRA, High right atrium; IVC, Inferior vena cava; LLA, Low left atrium; LRA, Low right atrium; SVC, Superior vena cava