(FIT)-Module 2 Lectures: Invasive Diagnosis and Treatment Part 1-Use of Overdrive Pacing - Entrainment in Supraventricular Tachycardia (Miller)

Video Transcription

Video Summary

This video, presented by John Miller, focuses on the principles and applications of overdrive pacing in the context of supraventricular tachycardia (SVT), often referred to as entrainment. However, Miller clarifies that while overdrive pacing is commonly called entrainment, this isn't always the case, highlighting the necessity of understanding subtle differences. The primary objectives include understanding the core principles and proper techniques, distinguishing responses to overdrive pacing and their diagnostic implications, recognizing entrainment features such as fusion, and interpreting unexpected responses, like non-propagated tachycardia termination.<br /><br />Overdrive pacing during SVT from either the atrium or ventricle can provide valuable diagnostic information. Responses can show entrainment or non-entrainment, with potential informative implications. For instance, atrial overdrive pacing might reveal atrial activation fusion, indicating macro-reentry. The post-pacing interval minus the tachycardia cycle length serves as an index of the spatial distance from the pacing site to part of the re-entrant circuit, and by comparing this index from various sites, one can create an entrainment map to aid in tailoring ablation targets.<br /><br />The video addresses challenges in distinguishing between focal and re-entrant tachycardias using entrainment techniques and how macro-reentry can be identified by the presence of fusion. Other discussions include the importance of electrogram timing and sequence in validating ablation targets, the pitfalls of certain responses, and tools for interpretation, focusing on avoiding common misinterpretations and recognizing pseudo-responses. The content emphasizes the complexity and detailed nature necessary for successful implementation of these electrophysiology methods for both diagnostic and therapeutic applications in cardiac arrhythmias.

Keywords

overdrive pacing

supraventricular tachycardia

SVT

entrainment

fusion

macro-reentry

post-pacing interval

tachycardia cycle length

ablation targets

electrogram timing