Basic Basic electrophysiologyelectrophysiologyDr Mohamad AbdelshafyDr Mohamad AbdelshafyAssistant lecturer Suez Canal Assistant lecturer Suez Canal UniversityUniversity

ObjectivesObjectives General objectives of EP-study:General objectives of EP-study: - Induce tachycardia & study its - Induce tachycardia & study its

mechanismmechanism - Assess the integrity or - Assess the integrity or

function of conductive systemfunction of conductive system

Sinus node function AVN function

EPS procedureEPS procedure Vascular access (Venous – Vascular access (Venous –

arterial)arterial) Electrode catheter (contact Electrode catheter (contact

mapping – pacing)mapping – pacing) Catheter positionCatheter position Multichannel recording system + Multichannel recording system +

programmable stimulator programmable stimulator

Electrode catheterElectrode catheter

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

Connecting port

14 3 2 1

Dist.Prox.

Ablation catheterAblation catheter RF-current applic.

Catheter positionCatheter position SVT VTSVT VT HRA SAN HRAHRA SAN HRA His AV cond HisHis AV cond His RVA RVA +/- RVA RVA +/-

LVALVA CS SCV punctureCS SCV puncture Recording from all major 4 chambers & His position

Catheter positionCatheter positionRAO LAO

CS

His

RV

Intracardiac electrogramIntracardiac electrogram

Bipolar recording of cardiac Bipolar recording of cardiac elecrical activity (localized area)elecrical activity (localized area)

High frequency, high amplitude High frequency, high amplitude signal (tissue depolar.) in contact signal (tissue depolar.) in contact with recording electrodewith recording electrode

Nomenclature …….Nomenclature ……. Sequence of activationSequence of activation

Nomenclature & Nomenclature & Measurement of baseline Measurement of baseline cond. intervalscond. intervals

Cycle length = 60.000/ HR length of time bet. Heart beats

V

A

V

SCLP

His electrogram (3 components) low RA- His-upper RV-no AVN

baseline cond. intervalsbaseline cond. intervals

SCL= interval bet. 2 successive A SCL= interval bet. 2 successive A waveswaves

AH interval ( 50—120 msec) AVNAH interval ( 50—120 msec) AVN HV interval (35 – 55 msec) His- HV interval (35 – 55 msec) His-

purkpurk His deflection (cond. Via His bundle)His deflection (cond. Via His bundle) IACT (not basic) = interval bet SAN & IACT (not basic) = interval bet SAN &

HisHis

Sequence of activation-Sequence of activation-catheter setupcatheter setup

SAN functionSAN function

Pacing (site- type- differentiation)Pacing (site- type- differentiation) Tests of SAN function:Tests of SAN function: -SNRT (assess SAN automaticity) (up -SNRT (assess SAN automaticity) (up

to 1500 msec) - variable with HRto 1500 msec) - variable with HR -cSNRT (SNRT-BSL) up to 525 msec-cSNRT (SNRT-BSL) up to 525 msec - SACT (50-125 msec) assess cond. of - SACT (50-125 msec) assess cond. of

impulse from SAN to adjacent atrial impulse from SAN to adjacent atrial tiss tiss

SAN functionSAN function

S1A550

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

400

Time = 30 sec

HRA

Recovery interval

SAN functionSAN function

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

8 paced beats

Assessment of AVN functionAssessment of AVN function

Pacing:Pacing: sitesite type (burst –ramp)type (burst –ramp)Extrastimulation (site – number- Extrastimulation (site – number-

coupling intervals)coupling intervals)Differentiation (atrial- ventricular)Differentiation (atrial- ventricular)

Atrial pacingAtrial pacing

A V

A V

S1

Pacing interval

V pacingV pacing

A V V A

Tests of AVN functionTests of AVN function

Antegrade 1:1 AV conductionAntegrade 1:1 AV conduction Antegrade WCLAntegrade WCL Retrograde 1:1 VA conductionRetrograde 1:1 VA conduction Retrograde WCLRetrograde WCL AVN/ERPAVN/ERP

1:1 AV cond.1:1 AV cond.

A V

AVN/ERPAVN/ERP

400/350

S1 S2

1:1 VA cond.1:1 VA cond.

PCL= 300 msec

V A

Retrograde sequence of activation

VA dissociationVA dissociation

PCL=260 msec

A A

V V V

V. extrastimV. extrastim

S1

SS2