THE UPPER TURNOVER SITE IN THE REENTRY CIRCUIT OF COMMON ATRIAL-FLUTTER

The upper turnover site of the reentry circuit of common atrial flutte r was examined with the uses of atrial activation mapping and extrasti mulus techniques during atrial flutter. The findings suggest that it i s anterior to the orifice of the superior vena cava, i.e., between the superior vena cava and tricuspid annulus.