Takanari Ishinaga

STUDY ON THE GENESIS OF THE DOUBLE POTENTIAL RECORDED IN THE HIGH RIGHT ATRIUM IN ATRIAL FLUTTER AND ITS ROLE IN THE REENTRY CIRCUIT OF ATRIAL FLUTTER

To investigate the genesis of the double potential (DP), which is two separate waves, and its role in the reentry circuit of atrial flutter (AF), we performed overdrive pacing (ODP) from the high right atrium (HRA) in six cases of spontaneous AF in which the DP was recorded in the HRA. In four of the six cases, when the DP was arbitrarily designated D1 and D2, D1 and D2 showed progressive fusion during ODP. In addition, the D1 return cycle, immediately after the termination of ODP, corresponded to the AF cycle, and the D2 return cycle corresponded to the pacing cycle. This may indicate that the DP is caused by the collision of two directional waves. Furthermore, it is suggested that the HRA plays an important role in preventing a possible shortcutting of reentry waves and in stabilizing the reentry circuit of AF.

Shift of Atrial Reentrant Tachycardia with Transient Entrainment to an Uncommon and a Common Type of Atrial Flutter

Atrial reentrant tachycardia (ART) which demonstrated transient entrainment shifted to an uncommon type of atrial flutter (AF) with premature atrial stimulation, and then returned to ART spontaneously, Subsequently, this ART shifted to a common type of AF by rapid atrial pacing, which was further transformed into an uncommon type of AF and finally terminated by rapid atrial pacing. The mechanism of AF in clinical cases is still controversial, but in this case, AF, both uncommon and common types, is considered due to macro‐reentry within the atria. To explain (he shift of ART to AF and mutual transformation between common and uncommon type of AF, we made a schematic figure of reentry loop within (he atria of ART and AF.