Entrainment
Basic principles
Prerequisites for entrainment
- Reentrant circuit
- Excitable gap
- No entrance block
Identifying entrainment
- Constant fusion
- Progressive fusion
Constant fusion
Progressive fusion
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
Example - Entrainment in Atrial flutter
Catheters
Entrainment
Pacing from lateral RA
Pacing from lateral RA
Pacing from lateral RA
Pacing from lateral RA
Pacing from lateral RA
Pacing from lateral Isthmus
Ventricular tachycardia
Example
Example
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
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
Courier delivery
Courier delivery
Courier delivery
Sequential vs parallel
Passing through a closed door
Passing through closed door
Last man standing
Through the looking glass
- Principles can be applied in reverse direction
- Very useful to remember in WQRST
His refr PVC in NQRST
Septal refr PAC in WQRST
Spontaneous termination of NQRST with 1:1 VA
VOP in narrow QRS tachycardia with 1:1 VA
Summary
- Understand principles rather than rules
- Visualisation of principles
- Ability to apply maneuvers in "reverse" makes it easier in WQRST