Decremental conduction property in the slow conduction zone of adenosine-sensitive atrial tachycardia.

In the case of adenosine-sensitive atrial tachycardia originating near the atrioventricular (AV) node, overdrive pacing from the anterior right atrium showed constant and progressive fusion, indicating that the pacing site is proximal to slow conduction. Shortening the pacing cycle length prolonged conduction times to the orthodromic capture sites; they remained unchanged at the antidromic capture sites. Limited decremental conduction property in the slow conduction zone supports the hypothesis that AV node-like tissue remnants along the AV annulus are involved.