Demonstration of intra-atrial conduction delay, block, gap and reentry: a report of two cases.

REENTRY HAS BEEN FREQUENTLY proposed as a mechanism for a variety of cardiac arrhythmias. For certain types of arrhythmias, the role of reentry appears well established.1 10 While intra-atrial reentry has long been suspected as a mechanism of some form of atrial arrhythmias, the phenomena of interor intra-atrial reentry in man have rarely been documented.8 11 The inability to demonstrate interor intra-atrial reentry in part relates to the limited number of intra-atrial recordings that can be used during routine electrophysiological studies.8' 11, 12 In this report we present observations in two patients showing the phenomena of intra-atrial conduction delay, block, gap and reentry.