Abstract
Background: Differentiation between atrioventricular nodal reentry tachycardia (AVNRT) and accessory pathway-mediated atrioventricular reentrant tachycardia (AVRT) is challenging even during electrophysiological testing.
Objective: To use the beginning of RV entrainment to differentiate between AVRT and AVNRT as an independent criterion with high sensitivity and specificity.
Methods: We studied 50 patients with supra-ventricular tachycardia. RV pacing was performed 10-40ms faster than tachycardia. Once a fixed QRS morphology was observed in 12-leads ECG, we determined after which beat the atrial perpetuation had been achieved.
Results: In all the 19 patients who had AVRT, atrial perpetuation occurred from the first beat. While, in all 31 cases of AVNRT atrial perpetuation occurred within the 2 beat or more.
Conclusion: Analysing the beginning of ventricular entrainment can indeed differentiate between AVRT and AVNRT cases easily with a high positive predictive value.
Keywords: Supra-ventricular tachycardia; Atrio-ventricular reentry tachycardia; AV Reentry tachycardia; Entrainment, Electrophysiological study, EP lab.