PO-05-223 EXAGGERATED DECREMENTAL CONDUCTION ACROSS THE CAVO-TRICUSPID ISTHMUS IN TYPICAL ATRIAL FLUTTER.

Typical atrial flutter (AFL) is a common arrhythmia and ablation often utilized. However, when patient with AFL in sinus rhythm, there no known electrophysiologic finding to suggest that likely. Whereas, atrioventricular nodal reentry tachycardia, an AH jump seen or Wolff-Parkinson White Syndrome, accessory pathway conduction present during testing. The critical isthmus at the cavotricuspid (CTI). To determine properties across CTI patients without AFL. study group comprised of 5 confirmed who were undergoing Sinus rhythm was restored (atrial burst pacing electrical cardioversion) then assessed by fixed various cycle lengths extra-stimuli 2 different trains. Conduction measured from medial lateral medial. control EP for reasons not related (4 left-sided 1 traumatic syncope bifascicular block on electrocardiogram) same protocol performed. In group, trans-CTI time increased average 67.8 msec (the range 53 90 msec, figure 1a). 20.8 (range 32 1b); increase noted have paroxysmal SVT consistent intracardiac electrogram but it non-sustained could be mapped entrained. Decremental all patients. those AFL, exaggerated compared (an vs msec). Further ongoing number subjects. If this persists, decremental suggests prone develop can used as potential guide inducible ablation.