BACKGROUND: There is little information about the surface expression of non-cavotricuspid isthmus (CTI)-dependent @entity4032 ( @entity4032 ) or left atrial (LA) flutter circuits. METHODS AND RESULTS: We retrospectively evaluated 32 episodes (in 26 @entity1 ) of atypical @entity4032 and 22 episodes (in 21 @entity1 ) of LA flutter. The surface ECG of 13 @entity1 with lower-loop reentry was similar to that of their pattern during counterclockwise (CCW) CTI @entity956 ( @entity956 ), except for decreased amplitude of the terminal forces in the inferior leads. In 11 of 24 episodes characterized by high or multiple breaks over the crista, the ECG showed changes that depended on the initial activation sequence of the LA. In 7 of 8 episodes of upper-loop reentry, the ECG pattern completely mimicked that for clockwise (CW) CTI @entity956 . All 11 @entity1 with an LA septal circuit showed a typical ECG pattern characterized by prominent forces in lead V1 with flat deflections in the other surface leads. Eleven @entity1 with other LA circuits had a more variable pattern but showed decreased voltage in the inferior leads compared with that of a group with CCW-CTI @entity956 (1.6+/-1 vs 2.68+/-0.7 mV, respectively; P<0.05). CONCLUSIONS: The @entity4032 surface-ECG patterns different from those of CCW or CW-CTI could still be CTI dependent. In contrast, a typical CW-CTI surface pattern was always seen in @entity1 with upper-loop reentry, which was non-CTI dependent. LA @entity956 circuits had either flat or low-amplitude forces in the inferior leads.

Surface electrocardiographic characteristics of right and left XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity4032 :: ('MESH:D059446', 'Disease') :: ['RA', 'right atrial'] @entity956 :: ('MESH:D001282', 'Disease') :: ['atrial flutter', 'AFL']
@entity956 :: (MESH:D001282,Disease) :: ['atrial flutter']
