Characterization of slow conduction in the common type of atrial flutter : using transient entrainment

In transient entrainment of common AF, conduction time from stimulus to CSp during HRAd pacing was always longer than that from stimulus to HRAd during CSp pacing. It was also longer than that from stimulus to CSp during HRAd pacing in 5 control patients without common AF in sinus rhythm. In HRAd pacing, return cycle at the proximal high lateral right atrium was almost equal to the pacing cycle length, or almost equal to or slightly shorter than the flutter cycle length (AFCL). Return cycle at CSp was almost equal to AFCL. Return cycle at an endocardial recording site after transient entrainment in common AF does not always exhibit an uniform pattern, affected by the relative location of and the distance between the recording site, the pacing site, the reentrant circuit and the area of slow conduction