This document outlines the minimum protocol for an electrophysiology study (EPS), including testing of sinus node function, refractory periods, and extrastimulus testing. Key points covered include measuring effective and functional refractory periods of the atria, AV node, His-Purkinje system, and ventricles. Incremental pacing is also discussed. The goal of the protocol is to evaluate conduction properties and provoke arrhythmias for diagnostic purposes.

1. EP STUDY
MINIMUM PROTOCOL

2. WE’VE TALKED ABOUT…
EQUIPMENT
PATIENT PREPARATION
RELEVANT ANATOMY
CATHETERS and PLACEMENT
BASIC INTERVALS
TESTS OF SN FUNCTION

3. AND NOW…
EQUIPMENT
PATIENT PREPARATION
RELEVANT ANATOMY
CATHETERS and PLACEMENT
BASIC INTERVALS
TESTS OF SN FUNCTION
ATRIAL and VENTRICULAR EXTRASTIMULUS
TESTING
REFRACTORY PERIODS
‘GAP’
INCREMENTAL PACING
MINIMUM PROTOCOL FOR DIAGNOSTIC EPS

4. EXTRASTIMULUS TESTING

5. 5
Drive train with a single extra stimulus
S1 S1 S1 S1 S1 S1 S1 S1 S2Sensed
PAUSEDRIVETRAIN
S1-S2
Interval
Sense-S1
Interval
8 paced beat drive train – EP steady state
Extrastimulus
(Coupling interval)

6. Extra stimuli
S 1 S 1 S 1 S 1 S 1 S 1 S 1 S 1 S 2Sensed
DRIVETRAIN
S 3 S 4
S1 S1 S1 S1 S1 S1 S1 S1 S2Sensed
DRIVETRAIN
S 1 S 1 S 1 S 1 S 1 S 1 S 1 S 1 S2Sensed
DRIVETRAIN
S3
Single
Double
Triple

7. Atrial Extrastimulus testing
• Dynamic properties of AVN and HPS
conduction
• AVN and RA refractory periods

8. Atrial Extrastimulus testing
• Dynamic properties of AVN and HPS
conduction
• AVN and RA refractory periods
• Dual AVN physiology

9. Atrial Extrastimulus testing
• Dynamic properties of AVN and HPS
conduction
• AVN and RA refractory periods
• Dual AVN physiology
• Arrhythmia induction

10. S2 with long coupling interval
Conduction at
fairly constant
velocity
A2H2 equal or
slightly more than
A1H1

11. A1H1 80 ms ~ A2H2 95 ms
S1A1 ~ S2A2 ~ 55 ms
H1V1 ~ H2V2 ~ 50 ms

12. S2 with short coupling interval
Slowing of
Conduction
A1H1 < A2H2

13. A1H1 80 ms
A2H2 140 ms

14. S2 with shorter coupling interval
Blocked AES
at AVN

16. Ventricular Extrastimulus testing
• Retrograde conduction over HPS and AVN
• Accessory pathway conduction
• Arrhythmia induction

17. Ventricular Extrastimulus testing
• Retrograde conduction over HPS and AVN
• Accessory pathway conduction
• Arrhythmia induction
• Stimulation at RV apex conventionally –
RV apex Stim – distal RBB – HPS – AVN – RA

18. S2 with long coupling interval

19. H buried in V
V1A1 almost equal to V2A2
Earliest atrial
activation in HBE
Atleast 30 ms
before HRA
Proximal-to-distal
CS activation
CONCENTRIC
ATRIAL
ACTIVATION

20. S2 with short coupling interval

21. S2 with shorter coupling interval

22. S2 with short coupling interval with
short drive cycle length
Blocked VES at AVN
VA block
Differs with
– ES coupling interval
– Drive cycle length

23. S2 with short coupling interval
Tissue latency in
local evoked
response
Occurs just above
the tissue refractory
period

24. Even shorter coupling interval
Blocked VES locally at
RV apex
Loss of ventricular
capture

25. Ventricular Extrastimulus testing
• Other ‘Normal’ responses
– No VA conduction at all
• Atropine, Isoprenaline
• No VA conduction despite drugs

26. Ventricular Extrastimulus testing
• Other ‘Normal’ responses
– No VA conduction at all
• Atropine, Isoprenaline
• No VA conduction despite drugs
– Retrograde exit site from AV node maybe near CS
ostium rather than HBE – earliest atrial activation
at Proximal CS

27. Ventricular Extrastimulus testing
• Other ‘Normal’ responses
– No VA conduction at all
• Atropine, Isoprenaline
• No VA conduction despite drugs
– Retrograde exit site from AV node maybe near CS
ostium rather than HBE – earliest atrial activation
at Proximal CS
• Maneuvers to prove accessory pathway

28. REFRACTORY PERIODS

29. EFFECTIVE Refractory Period
• ERP of a tissue

30. EFFECTIVE Refractory Period
• ERP of a tissue (or a structure)

31. EFFECTIVE Refractory Period
• ERP of a tissue (or a structure) is the LONGEST
coupling interval that fails to capture the
tissue

32. EFFECTIVE Refractory Period
• ERP of a tissue (or a structure) is the LONGEST
coupling interval that fails to capture the
tissue (or be conducted over the structure)

33. FUNCTIONAL Refractory Period
• FRP of a tissue (or a structure) is the
SHORTEST ‘output’ coupling interval that can
be elicited from a tissue (or structure) by any
‘input’ interval

34. FUNCTIONAL Refractory Period
• FRP of a tissue (or a structure) is the
SHORTEST ‘output’ coupling interval that can
be elicited from a tissue (or structure) by any
‘input’ interval
S1-A1-H1-V1 S2-A2-H2-V2
AVN
HPS
AV conduction system

35. RELATIVE Refractory Period
• RRP of a tissue (or a structure) is the ‘input’
interval at which the ‘output’ interval just
begins to differ from ‘input’ interval

36. RELATIVE Refractory Period
• RRP of a tissue (or a structure) is the ‘input’
interval at which the ‘output’ interval just
begins to differ from ‘input’ interval
• This is the point at which Latency or
Decremental conduction begins to occur
• Least commonly measured

37. • In all tissues, ERP and FRP are ‘length-
dependent’
• So, measured using atleast 2 different drive
cycle lengths

38. AVNERP
Longest A1A2
interval that fails
to capture HB
A1A2 maybe longer
than S1S2 due to
tissue latency

39. AVNFRP
Shortest H1H2 in
response to any
A1A2 interval

40. AVNRRP
Longest A1A2
interval at which
A2H2 exceeds
A1H1

42. Normal range of refractory periods (ms)
ERP Atria ERP AVN FRP AVN ERP HPS ERP V
150-350 230-430 330-530 330-450 190-290
*Denes, Akhtar, Durrer, Josephsen series

43. GAP phenomena
ES
conducted
as LBBB

46. INCREMENTAL ATRIAL PACING

48. INCREMENTAL VENTRICULAR PACING

49. MINIMUM PROTOCOL
• Basic intervals
• SNRT and CSNRT
• AES – AVNERP
• AV WCL
• VES – VERP
• VA WCL

50. • Arrhythmia induction

51. TO BE CONTINUED….

52. ….NEXT presentations
• Atrial arrhythmias
• Ventricular Pre-excitation and AVRT
• Ventricular arrhythmias
• Catheter ablation