atrioventricular dissociation

n.

A condition in which the atria and ventricles contract independently, especially as resulting from the slowing of an atrial pacemaker or the acceleration of a ventricular pacemaker.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.