Diagnostic Pacing Maneuvers for Supraventricular Tachycardia: Part 1

Abstract

This two-part manuscript reviews diagnostic pacing maneuvers for supraventricular tachycardia (SVT). Part one will involve a detailed consideration of ventricular overdrive pacing (VOP), since this pacing maneuver provides the diagnosis in the majority of cases. This will include a review of the post-VOP response, fusion during entrainment, the importance of the VOP site, quantitative results of entrainment such as the postpacing interval, differential entrainment, and new criteria derived from features found at the beginning of the VOP train. There is a considerable literature on this topic, and this review is by no means meant to be all-encompassing. Rather, we hope to clearly explain and illustrate the physiology, strengths, and weaknesses of what we consider to be the most important and commonly employed diagnostic pacing maneuvers, that is, those that trainees in cardiac electrophysiology should be well familiar with at a minimum. \

Regular, narrow QRS, long RP tachycardia – what is the mechanism?

“…During ventricular overdrive pacing the following criteria are assessed: (A) post-pacing response (V-A-V versus V‑A-A-V) and (B) post-pacing interval (PPI) minus tachycardia cycle length (TCL). A V-A-A-V response strongly suggests atrial tachycardia, while a V-A-V response is encountered in both AVRT and AVNRT [1]. The PPI-TCL differentiates an atypical AVNRT from an AVRT with a discriminant value of 115 msec (>115 msec suggests atypical AVNRT, while <115 msec an AVRT) [2].…”

Atrioventricular Nodal Reentrant Tachycardia in Implantable Cardioverter Defibrillators: Diagnosis and Troubleshooting

“…), especially in the atypical variant. Spontaneous termination of AVNRT may occur either with an “A” or a “V,” whereas termination with an “A” in the context of a tachycardia with 1:1 AV ratio makes atrial tachycardia (AT) unlikely, and termination with a “V” makes ventricular tachycardia (VT) unlikely . It also may be terminated by a PVC if this is early enough to penetrate into the excitable gap of the circuit and render the antegrade limb refractory.…”

Atrial Overdrive Pacing: Is VA Linking Present?

“…VA block during VOP excludes AVRT and strongly favors AT, but AVNRT with retrograde block in the lower common pathway is a potential differential diagnosis. AOP to assess for VA linking by comparing the VA interval on the first return beat to the VA during tachycardia can be useful to differentiate AVNRT (presence of VA linking with difference <10 milliseconds) from atrial tachycardia (absence of VA linking) .…”