Ventriculo-atrial conduction in the ovine heart, caused by premature ventricular complexes

In humans, and certain animals, the atrioventricular conduction system is capable of bidirectional conduction. Depolarization impulses, originating in the ventricle itself, may thus be conducted in a retrograde direction towards the atria. Two common causes for this phenomenon of ventriculo-atrial (retrograde) conduction are premature ventricular complexes and ventricular pacing. The surface electrocardiogram can be used for the detection of such retrogradely conducted beats. The purpose of this study was to investigate the possibility of ventriculo-atrial conduction in Dorper sheep. Premature ventricular complexes in eight healthy Dorper wethers were induced and it was possible to document retrogradely conducted beats on the surface electrocardiogram in all of them. It is concluded that the Dorper sheep heart is capable of ventriculo-atrial conduction.