The VA relationship after differential atrial overdrive pacing: a novel tool for the diagnosis of atrial tachycardia in the electrophysiologic laboratory.
BACKGROUND
Despite recent advances in clinical electrophysiology, diagnosis of atrial tachycardia (AT) originating near Koch's triangle remains challenging. We sought a novel technique for rapid and accurate diagnosis of AT in the electrophysiologic laboratory.


METHODS
Sixty-two supraventricular tachycardias including 18 ATs (10 ATs arising from near Koch's triangle), 32 atrioventricular nodal reentrant tachycardias (AVNRTs), and 12 orthodromic reciprocating tachycardias (ORTs) were studied. Overdrive pacing during the tachycardia from different atrial sites was performed, and the maximal difference in the postpacing VA intervals (last captured ventricular electrogram to the earliest atrial electrogram of the initial beat after pacing) among the different pacing sites was calculated (delta-VA interval).


RESULTS
The delta-VA intervals were >14 ms in all AT patients and <14 ms in all AVNRT/ORT patients, and thus, the delta-VA interval was diagnostic for AT with the sensitivity, specificity, and positive and negative predictive values all being 100%. When the diagnostic value of the delta-VA interval and conventional maneuvers were compared for differentiating AT from atypical AVNRT, both a delta-VA interval >14 ms and "atrial-atrial-ventricular" response after overdrive ventricular pacing during the tachycardia were diagnostic. However, the "atrial-atrial-ventricular" response criterion was available in only 52% of the patients because of poor ventriculoatrial conduction.


CONCLUSIONS
The delta-VA interval was useful for diagnosing AT irrespective of patient conditions such as ventriculoatrial conduction.
Maruyama
Mitsunori
M
First Department of Internal Medicine, Nippon Medical School, Tokyo, Japan. maru@nms.ac.jp
Kobayashi
Yoshinori
Y
Miyauchi
Yasushi
Y
Ino
Takeshi
T
Atarashi
Hirotsugu
H
Katoh
Takao
T
Mizuno
Kyoichi
K
D002304:Cardiac Pacing, Artificial / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis*; D054139:Tachycardia, Reciprocating / Q000175:diagnosis*