Entrainment, Basic principles of EP maneuvers

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Raja Selvaraj

Professor of Cardiology, JIPMER

Entrainment

Basic principles

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Prerequisites for entrainment

  • Reentrant circuit
  • Excitable gap
  • No entrance block

Identifying entrainment

  • Constant fusion
  • Progressive fusion

Constant fusion

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Progressive fusion

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Locate site of pacing in relation to tachycardia circuit

  • Deviation from morphology indicates extent of capture by antidromic wavefront
  • Deviation from cycle length indicates distance from circuit

PPI

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Example - Entrainment in Atrial flutter

Catheters

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Entrainment

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Pacing from lateral RA

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Pacing from lateral RA

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Pacing from lateral RA

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Pacing from lateral RA

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Pacing from lateral RA

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Pacing from lateral Isthmus

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Ventricular tachycardia

Example

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Example

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Basic principles of EP maneuvers

Basic principles

  • Understand principles rather than rote learn maneuvers
  • Understand multiple analogous situations from single principles
  • Visual understanding

Start right !

  • Learn to use the stimulator
  • Learn to set up sync
  • Learn to measure
  • Repeatedly use early in career

Three diagnoses

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Critical parts of circuit

  • AT
    • Atrium
  • AVRT
    • Atrium and ventricle
  • AVNRT
    • None

Distance gives perspective

  • Narrow QRS tachycardia
    • Ventricular overdrive pacing
    • PVCs
  • Wide QRS tachycardia
    • Atrial overdrive pacing
    • PACs

Waypoint

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Courier delivery

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Courier delivery

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Courier delivery

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Sequential vs parallel

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Passing through a closed door

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Passing through closed door

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Last man standing

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Through the looking glass

  • Principles can be applied in reverse direction
  • Very useful to remember in WQRST

His refr PVC in NQRST

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Septal refr PAC in WQRST

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Spontaneous termination of NQRST with 1:1 VA

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VOP in narrow QRS tachycardia with 1:1 VA

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Summary

  • Understand principles rather than rules
  • Visualisation of principles
  • Ability to apply maneuvers in "reverse" makes it easier in WQRST