Dr Mervat Aboulmaaty prof. of Cardiology Ain Shams University

Dr Rehab Hamdy

Lecturer of Cardiology Elazhar University 2014

Basic electrophysiology

The normal conductive system of the heart

SAN

AVN

His

Objectives

General objectives of EP-study

Assess the integrity or function of the

Conductive System

Induce tachycardia & study its mechanism

RF ablation

Sinus node function AVNN function

EPS procedure

Vascular access (Venous – arterial)

Electrode catheter (mapping – pacing)

Catheter position (Cath Lab)

Multichannel recording system + programmable stimulator

3D Electroanatomical Mapping

Electrode catheter

Bipolar intracardiac recording (localized leectrical activity- depolarization of tissue)

Connecting port

1 4 3 2 1

Dist. Prox.

EP Lab = Cath Room + EPS machine + Ablator

+/- 3D mapping

Floroا

Stimulator

EPS Machine RF ablator & Infusion Pump

جهاز القسطرة

Display screen: The first page is 12 lead surface ECG

second page :intracardiac ECG (local electrograms)

Ablation catheter

Femoral sheaths

Subclavian venous sheath

CS catheter

Ablator

Indifferent electrode

Ablation catheter

Temp: time: Impedence:

Catheter position

SVT VT

HRA SAN HRA

His AV cond His

RVA RVA +/- LVA

CS SCV/IVC

Recording from RA, RV, His , CS

Catheter Placement and recording

HRA

CS

HIS

RV

Catheter position RAO LAO

CS

His

RV

CS ABL

ABL

Catheters projection in RAO and LAO views Cs catheter (deflectable) inserted through IVC

LAO 20 Pole mapping catheter catheter (HALLO) and long sheaths for stability

Halo catheter

mapping the RA

CS

His

ABL

Long Sheath

Ablation Catheters

Millisecond (msec) - The unit of time used in

measuring intervals. 0.001 of a second.

Heart rate (HR)- The number of

depolarizations per minute.

Cycle length (CL) - msec it takes from a

single point in one cardiac cycle to the

same point in the next cardiac cycle.

CL= 60000 / HR msec

HR= 60000 / CL bpm

Measurements

BASIC DEFINITIONS: Nomenclature

S : Sinus activation

A : Atrial activation

H : His Bundle activation

V : Ventricular activation

S1: Regularly delivered stimulus in a series

A1: Atrial activation resulting from S1

H1: His bundle activation resulting from S1

V1: Ventricular activation resulting from S1

S2: First premature stimulus

S3: Second premature stimulus

A2: Atrial activation resulting from S2

H3: His bundle activation resulting from S3

Refractory Period

Effective refractory period (ERP) is the longest S1-S2 that fails to depolarize the chamber being paced or the AV node.

Functional refractory period (FRP) is the shortest S1-S2 that depolarizes the chamber being paced or the AV node.

Catheter Placement – High Right Atrium (HRA)

Catheter Placement – Right Ventricular Apex (RVA)

Catheter Placement – His Bundle

Catheter Placement – Coronary Sinus

baseline cond. intervals

SCL= interval bet. 2 successive A waves

AH interval ( 50—120 msec) AVN

HV interval (35 – 55 msec) His-RV/QRS

His deflection (cond. Via His bundle)

Basic intracardiac recordings

Basic intracardiac measurements

SAN function

Pacing (site- type- differentiation)

Tests of SAN function:

-SNRT (assess SAN automaticity) (up to 1500 msec) - variable with HR

-cSNRT (SNRT-BSL) up to 525 msec

- SACT (50-125 msec) assess cond. of impulse from SAN to adjacent atrial tiss

SAN function

S1

A 550

SCL= 450 msec SNRT= 550 msec CSNRT= 150 msec

400

Time = 30 sec

HRA

Recovery interval

SAN function Sino Atrial Conduction Time

S1 A

Idea: reset the SAN – Narula method

580

Recovery interval= time of paced beat penetrates & resets SAN+SCL+time for spont. Beat to exit SAN = SCL+ 2 SACT SACT=580-450/2 = 65 msec

8 paced beats

Tests of AVN function

Antegrade 1:1 AV conduction

Antegrade WCL

Retrograde 1:1 VA conduction

Retrograde WCL

AVN/ERP

Atrial pacing 1:1 AV cond.

A V

Atrial pacing Weckebach AV block

A

V

A

V

A A

H

V

HIS

HIS

RA

R V

Basic ICECG Basic study

Atrial pacing, Wenckebach more yellow than purple

Atrial Extrastimulation To measure AVN/ERP

Atrial Extrastimulation to measure AVN/ERP

Atrial Extrastimulation AVN/ERP 500/280 msec

V pacing To measure retrograde AVN or detect AP

A V V A

1:1 VA cond.

PCL= 300 msec

V A

Retrograde sequence of activation

Concentric

V A V A

Ventricular Pacing VA dissociation

PCL=260 msec

A A

V V V

A A A

Ventricular Extrastimulation S1 S2

V1 V2

A1 A2

Ventricular Extrastimulation Decremental conduction

V1 V2

A2 A1

Ventricular Extrastimulation : ERP of retrograde limb of AVN

A1

S2 No V V1

Ventricular Tachycardia Study Induction by Extra stimulus and termination by Overdrive Pacing

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The CARTO XP System Components

• Location Pad

(external, ultra-low magnetic field emitter.)

• Patient Interface Unit (PIU)

• PC Windows NT 4 Workstation

• Communication Unit (COM)

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Location Pad

An External Ultra-Low Magnetic Field Emitter

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Catheter Tip Location

D1

D2

D3

The Triangulation Principle

The Fields possess Temporal and spatial distinguishing characteristics

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Location Pad Location Pad

Mapping Catheter

Reference Patch

Mapping Catheter

Reference Patch

Two Sensors: REF and MAP

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Carto Concept: Sequential Contact Mapping of Endocardium

What is new ??!! Patient with LVOT VT .CARTO 3 Mapping

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