This document describes equipment, catheters, and basic intervals used in electrophysiology (EP) studies. It discusses radiographic tables, EP equipment like cardiac stimulators and mapping/ablation catheters. Patient preparation includes fasting, IV access, monitoring equipment. EP catheters come in different sizes and have electrodes for recording electrical activity. Basic intervals measured include P wave to atrial interval, atrial-His bundle interval, His-ventricular interval, and sinus node recovery time. Drive train stimulation with single, double, or triple extra stimuli is used. The document continues with further discussions of EP protocols, arrhythmias, ablation, and pre-excitation pathways.

1. EP STUDY
EQUIPMENT
CATHETER PLACEMENT
BASIC INTERVALS
PERIODS

2. EQUIPMENT/PATIENT PREPARATION

3. EQUIPMENT
• Radiographic Table, Image intensifier
• Specialized EP equipment
– Cardiac stimulator
– Diagnostic and mapping catheters
– Data monitor and recorder
– RF energy generator
• Temporary pacemaker, External pacemaker
• External Defibrillator
• Hemodynamic monitoring
• Resuscitation equipment

4. PATIENT PREPARATION
• Stopping Anti-arrhythmics – 2-3 days
• Fasting – 6 hrs
• IV access
• ECG electrodes for 12 lead ECG and
Monitoring
• External Remote Defib pads
• Indifferent skin electrode in RFA
• Pulse Ox/NIBP/Invasive BP
• Conscious sedation

5. EP CATHETERS

6. EP Catheters
• Electrode catheters are used during EP testing for recording
and pacing.
• These catheters consist of insulated wires
• At the distal tip of the catheter, each wire is attached to an
electrode, which is exposed to the intracardiac surface.
• Proximal end of the catheter, wire is attached to a plug,
which can be connected to an external recording device
• Woven Dacron or polyurethane.

7. EP Catheters
Dacron Polyurethane
Advantage of stiffness that helps maintain
catheter shape with enough softness at
body temperature that allows formation
of loops
cannot be easily manipulated and
change shapes within the body
expensive less expensive

8. EP Catheters
• Electrode catheters come in different sizes -2 to 10 Fr.
• In adults, sizes 5, 6, and 7 Fr catheters are the most
commonly used
• Recordings derived from electrodes can be unipolar
(one pole) or bipolar (two poles).
• The electrodes are typically 1 to 2 mm in length
• The interelectrode distance can range from 1 to 10 mm
or more
• Catheters with a 2- or 5-mm interelectrode distance
are most commonly used

12. NUMBER OF ELECTRODES
2mm2mm 5mm
Quadrapolar 2-5-2
1234
Quadrapolar 5-5-5 Lum en
5mm5mm 5mm
LUMEN
1234
4 3 2 1
2 (bipolar), 3 (tripolar), 4 (quadripolar), 6 (hexapolar),
8 (octapolar), 10 (decapolar), 20 (duodecapolar)

13. Electrode Orientation
DISTALPROXIMAL
TIP
123456
1 DISTAL
2
3
4
RECORDING
DEVICE

15. EP Catheters
• Large number of multipolar electrode catheters have
been developed - facilitate placement of the catheter
in the desired place and fulfill various recording
requirements.
• Variety of preformed distal curve shapes and sizes.
• Multipolar recording electrode catheters are placed
within the coronary sinus (CS) or along the crista
terminalis in the right atrium (RA)
• Halo catheter is a multipolar catheter used to map
reentrant electrical activity around the tricuspid
annulus during RA macroreentry

16. Multipolar electrode catheters with different
preformed curve shapes.
Multipolar electrode catheters with
different electrode numbers and curve
shape. , Duodecapolar catheter,
quadripolar catheter, and Halo catheter.

17. A decapolar catheter with a distal ring
configuration (Lasso catheter) is used to record
electrical activity from the pulmonary vein.
Basket catheters capable of conforming to the
chamber size and shape have also been used
for mapping atrial and ventricular arrhythmias

20. EP Catheters
• Catheters can have a fixed or deflectable tip
• Steerable catheters (deflectable tip) allow
deflection of the tip of the catheter in one or
two directions in a single plane; some of these
catheters have asymmetrical bidirectional
deflectable curves
• Radiofrequency ablation catheters have three
different tips: 4 mm, 8 mm, and a cooled tip
(ranging between 3.5 mm and 5 mm)

23. Ablation catheters with different tip electrode
sizes and shapes. Left to right, Peanut 8-mm,
2-mm, 4-mm, and 8-mm tip electrodes.
Deflectable multipolar electrode catheters
with different curve sizes and shapes.

25. ANATOMY FOR EPS
CATHETER PLACEMENT

26. Standard Catheter Electrodes
• High RA
– Quadripolar
– Femoral route
– Tip - superolateral – near SVC/RA junction

27. Standard Catheter Electrodes
• RV apex
– Quadripolar
– Femoral route
– Tip – as close to RV apex as possible

28. Standard Catheter Electrodes
• Coronary Sinus
– Decapolar
– Easiest access via SVC - IJV/SCV route

29. Standard Catheter Electrodes
• His Bundle
– Quadripolar; 2-2-2
– Femoral route
– Tip – straddles tricuspid annulus in its superior
portion

30. Anatomy of RA
• Components
– RA appendage
– Venous part
– Vestibule, inferiorly near
TV annulus
– Septum
– Sulcus Terminalis / Crista
separates RAA and venous
part
– Sinus node situated in the
Sulcus terminalis at SVC –
RA junction

31. RAO view

32. Anatomy of RA - RAO view

39. BASIC EP INTERVALS AND
PROTOCOLS

43. Right, The distal portion of the CS is closer to the ventricle (originating as
great cardiac vein on the anterior wall); the CS crosses the atrioventricular
(AV) groove at the lateral margin and becomes an entirely atrial structure as
it empties into the right atrium (RA). Left, Thus, proximal CS recordings show
large atrial and small ventricular signals, whereas more distal recordings
show small atrial, large ventricular signals.

46. MEASUREMENT OF CONDUCTION
INTERVALS
• Range of screen or paper speed generally used is 100
to 400mm/sec
• To evaluate sinus node function 100mm/sec is
adequate
• Routine refractory period studies require slightly faster
speeds (150 to 200mm/sec)
• For detailed mapping of endocardial activation paper
speeds of ≥200mm/sec or more should be used.
• Accuracy at 100mm/sec is approx ± 5msec
• Accuracy at 400mm/sec is approx ± 1msec

47. P Wave-Atrial Interval
• The P wave-atrial interval is
measured from the first evidence
of sinus node depolarization,
whether on the intracardiac or
surface ECG, to the atrial
deflection as recorded in the HB
lead. It represents conduction
through the RA to the
inferoposterior interatrial septum
(in the region of the AVN and HB).
• The normal range of the PA
interval is 25 to 55 milliseconds
• Rarely, diseased atrial conduction
can underlie first-degree AV block,
indicated by a prolonged PA
interval. A short PA interval
suggests an ectopic source of atrial
activation.

48. Atrial–His Bundle Interval
• The AH interval is measured from
the first rapid deflection of the atrial
deflection in the HB recording to the
first evidence of HB depolarization
in the HB recording
• Is an approximation of the AVN
conduction time, because it
represents conduction time from
the low RA at the interatrial septum
through the AVN to the HB.
• The AH interval has a wide range in
normal subjects (55 to 125
milliseconds) and is markedly
influenced by the autonomic
nervous system

49. ASSESSMENT OF H-V INTERVAL
• Time from depolarization of proximal His
bundle to the onset of ventricular
depolarization ranges from 35 to 55 msec.
NOTE- RBB deflection invariably occurs 30msec
or less before ventricular activation. Thus ,
during sinus rhythm an apparent His
deflection of less than 30msec either
reflects recording of a bundle branch
potential or the presence of preexcitation.
• Shorter than 35msec – an accessory
pathway is usually present producing
ventricular preexcitation during sinus
rhythm.
• Prolonged H-V interval longer than 70msec
suggest a possible AV block
• More than 100 msec is severe abnormalitry
and warrants permanent pacemaker

56. 56
Drive train with a single extra stimulus
S1 S1 S1 S1 S1 S1 S1 S1 S2Sensed
PAUSEDRIVETRAIN
S1-S2
Interval
Sense-S1
Interval

57. 57
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

58. Sinus Node Recovery Time
• It is the interval measured in the HRA from the last paced complex to the
first spontaneous complex after the cessation of pacing
• Evaluate the effect of overdrive suppression on sinus node automaticity

60. When corrected for the underlying baseline sinus cycle length
CSNRT = SNRT – SCL
Pacing at several cycle lengths (e.g. 600, 500, 400, 350,
300)
Reasonable values: maximum SNRT < 1500 ms
maximum CSNRT < 550 ms

61. 61
SNRT:1180 CSNRT: SNRT- SINUS CYCLE LENGTH = 400

62. SACT- defined as the
conduction time between
sinus node and the adjacent
atrial tissue
A2A3 = A1A1 + 2 X SACT
SACT =(A2A3-A1A1) / 2
Ref. val. 50-115 ms

63. TO BE CONTINUED….

64. ….NEXT presentations
• Basic EP protocols
• Atrial arrhythmias
• Ventricular Pre-excitation and AVRT
• Ventricular arrhythmias
• Catheter ablation