wandering atrial pacemaker [AS, wandrian + L, passus + ME, maken] , a sinus arrhythmia with an atrial or junctional escape rhythm during the slow phase of the sinus rhythm. Frequently there are atrial fusion beats when impulse from the two pacing sources collide within the atrium. An accelerated junctional rhythm that competes with the sinus rhythm is often mislabeled “wandering pacemaker.”
