Authors : Bernhard Strohmer , Christiana Schernthaner and Maximilian Pichler
Abstract: Determination of tachycardia mechanism by electrophysiological techniques is essential for a definite diagnosis of paroxysmal supraventricular tachycardia and a prerequisite for a safe and efficacious ablation. The purpose of this study was to determine, whether simultaneous atrial and ventricular (AV) extrastimulation is useful for differentiating atrioventricular nodal reentrant tachycardia (AVNRT) from orthodromic atrioventricular reentrant tachycardia (AVRT) using a septal accessory pathway. Forty-eight consecutive patients underwent electrophysiological study with induction of 51 types of tachycardias. Based on standard criteria AVNRT was diagnosed in 40 patients (4 atypical AVNRT) and AVRT through a septal accessory pathway in 11 patients. The diagnostic value of simultaneous AV extrastimulation was tested and the preexcitation index (PI) was compared to that obtained with single and double ventricular extrastimulation. Simultaneous AV extrastimulation was applicable in all patients with AVNRT except in one patient with slow/slow form. This pacing maneuver resulted in atrial and/or ventricular preexcitation in 11% of tested patients (PI 115?35 ms). Simultaneous AV extrastimulation was applicable in 50% of patients with septal AVRT (PI 24?28 ms), whereas in the other half of patients loss of simultaneous capture was observed. Simultaneous AV extrastimulation is a useful and rapid pacing maneuver for differentiation of AVNRT from orthodromic AVRT through a septal accessory pathway. This pacing technique is valid as long as simultaneous capture is achieved during tachycardia and may complete commonly used diagnostic steps in paroxysmal junctional tachycardias.
Bernhard Strohmer , Christiana Schernthaner and Maximilian Pichler , 2005. Simultaneous Atrial and Ventricular Extrastimulation for Differentiation of Atrioventricular Nodal Reentrant Tachycardia from Orthodromic Atrioventricular Reentrant Tachycardia Using Septal Accessory Pathways . The Cardiology, 1: 74-80.