© 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
Effects of antiarrhythmic drug therapy on atrioventricular nodal function during atrial fibrillation in humans*
aDépartement de Physiologie-Explorations Fonctionnelles, CHU Bichat, Université Paris VII Paris, France; bCentre de Recherche, Section Cardiovasculaire, Hôpital du Sacré-Coeur, Université de Montréal Montréal, Canada; cDepartment of Surgery, Division of Cardiac Surgery, Hôpital du Sacré-Coeur, Université de Montréal Montréal, Canada; dDepartment of Physiology, Centre for Nonlinear Dynamics in Physiology and Medicine, McGill University McIntyre Medical Sciences Building, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
AIMS: To assess the effects of metoprolol and amiodarone on atrial and ventricular activity during atrial fibrillation (AF) in post-surgical patients, and to develop and use a mathematical model of the atrioventricular (AV) node during AF that incorporates parameters describing the properties of the AV node to evaluate the physiological basis of the drug effects.
METHODS AND RESULTS: Ten post-surgical patients were evaluated where three received no medical therapy, three received metoprolol, three received amiodarone, and one received both metoprolol and amiodarone. The medications led to increases of 37310 ms in the mean VV interval in treated patients, but much smaller changes in the mean AA intervals in the right and left atria. The mathematical model incorporating a random influence of the concealed conduction parameter was capable of reproducing the histograms of the VV intervals based on the input from the right atrium by systematically searching parameter space.
CONCLUSIONS: Changes in the ventricular rate are mainly due to the alteration in the AV nodal properties rather than changes in the atrial rhythm. The medications can display differential effects on the physiological properties of the AV node, and therefore the mathematical model may help to identify novel pharmacological targets.
Key Words: atrioventricular node, atrial fibrillation, modelling, concealed conduction, antiarrhythmic drugs
*Corresponding author. Tel.: +1 514 398 4338; fax: +1 514 398 7452. E-mail address: glass{at}cnd.mcgill.ca (L. Glass).