A novel guinea pig heart model for studying AV nodal conduction and triggered activity in vivo

A novel model is described that enables for the first time the recording of the His bundle electrogram (HBE), monophasic action potential (MAP), and early (EAD) and delayed (DAD) afterdepolarizations in the guinea pig heart in vivo. In this model, custom-made catheter electrodes have been used; their detailed design, a recipe for their construction, and the modes of their operation are given in detail. In addition, examples of experimental data obtained using this model are given. These include values of atrial-to-His bundle and His bundle-to-ventricle intervals, as well as DADs associated with digoxin-induced ventricular arrhythmias. The present model is a small and relatively inexpensive model in which studies of atrioventricular nodal conduction, as well as afterdepolarizations/triggered activity, can be performed in vivo.