Differential entrainment distinguishes atrioventricular nodal reentry tachycardia from atrioventricular reentrant tachycardia.
BACKGROUND
Entrainment from the right ventricular (RV) apex and the base has been used to distinguish atrioventricular reentrant tachycardia (AVRT) from atrioventricular nodal reentry tachycardia (AVNRT). The difference in the entrainment response from the RV apex in comparison with the RV base has not been tested.


METHODS
Fifty-nine consecutive patients referred for ablation of supraventricular tachycardia (SVT) were included. Entrainment of SVT was performed from the RV apex and base, pacing at 10-40-ms faster than the tachycardia cycle length. SA interval was calculated from stimulus to earliest atrial electrogram. Ventricle to atrium (VA) interval was measured from the RV electrogram (apex and base) to the earliest atrial electrogram during tachycardia. The SA-VA interval from apex and base was measured and the difference between them was calculated.


RESULTS
Thirty-six AVNRT and 23 AVRT patients were enrolled. Mean age was 44 ± 12 years; 52% were male. The [SA-VA]apex-[SA-VA]base was demonstrable in 84.7% of patients and measured -9.4 ± 6.6 in AVNRT and 10 ± 11.3 in AVRT, P < 0.001. The difference was negative for all AVNRT cases and positive for all septal accessory pathways (APs).


CONCLUSIONS
The difference between entrainment from the apex and base is readily performed and is diagnostic for all AVNRTs and septal APs.
Khan
Aamir H
AH
QE II Health Sciences Center, Dalhousie University, Halifax, Nova Scotia, Canada.
Khadem
Aliasghar
A
Basta
Magdy N
MN
Gardner
Martin J
MJ
Parkash
Ratika
R
Gula
Lorne J
LJ
Sapp
John L
JL
D058606:Accessory Atrioventricular Bundle / Q000175:diagnosis / Q000503:physiopathology; D000328:Adult; D017115:Catheter Ablation; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery