[Are double potentials an indication of reentry? Intra-atrial catheter mapping in atrial flutter]

A local doubling of atrial potentials was demonstrated in 40 out of 49 electrophysiological investigations with intraatrial catheter-mapping during atrial flutter. Such doubled potentials can be localized in small areas of the right atrium. In these circumscribed areas the distances between the doubled potentials vary. A predilection area inside the right atrium was not detected. The doubled potentials were found in different sites varying from patient to patient: 15 times in the upper, 13 times in the middle, and 12 times in the lower areas of the atrium. In each patient there was a particular reproducible place, where the doubled potentials were found. Sequential activation time mapping seems to show atrial excitation spreading from the area where the doubled potentials were found. We interpreted these findings as evidence of a reentry-circuit. However, the reentry-circuit apparently does not use preexisting anatomical obstacles, but rather a circumscribed pathological alteration in the atrium.