Basic electrophysiology Dr Mohamad Abdelshafy Assistant lecturer Suez Canal University.
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Transcript of Basic electrophysiology Dr Mohamad Abdelshafy Assistant lecturer Suez Canal University.
Basic Basic electrophysiologyelectrophysiology
Dr Mohamad AbdelshafyDr Mohamad Abdelshafy
Assistant 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