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Basic electrophysiology

Basic electrophysiology. Dr Mohamad Abdelshafy Assistant lecturer Suez Canal University. Objectives. General objectives of EP-study: - Induce tachycardia & study its mechanism - Assess the integrity or function of conductive system. Sinus node function. AVN function.

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Basic electrophysiology

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  1. Basic electrophysiology Dr MohamadAbdelshafy Assistant lecturer Suez Canal University

  2. Objectives • General objectives of EP-study: - Induce tachycardia & study its mechanism - Assess the integrity or function of conductive system Sinus node function AVN function

  3. EPS procedure • Vascular access (Venous – arterial) • Electrode catheter (contact mapping – pacing) • Catheter position • Multichannel recording system + programmable stimulator

  4. Electrode catheter Connecting port 1 4 3 2 1 Dist. Prox. Bipolar intracardiac recording (localized leectrical activity- depolarization of tissue)

  5. Ablation catheter RF-current applic.

  6. Catheter position • SVT VT HRA SAN HRA His AV cond His RVA RVA +/- LVA CS SCV puncture Recording from all major 4 chambers & His position

  7. Catheter position RAO LAO His CS RV

  8. Intracardiac electrogram • Bipolar recording of cardiac elecrical activity (localized area) • High frequency, high amplitude signal (tissue depolar.) in contact with recording electrode • Nomenclature ……. • Sequence of activation

  9. Nomenclature & Measurement of baseline cond. intervals His electrogram (3 components) low RA- His-upper RV-no AVN P SCL A V V Cycle length = 60.000/ HR length of time bet. Heart beats

  10. baseline cond. intervals • SCL= interval bet. 2 successive A waves • AH interval ( 50—120 msec) AVN • HV interval (35 – 55 msec) His- purk • His deflection (cond. Via His bundle) • IACT (not basic) = interval bet SAN & His

  11. Sequence of activation-catheter setup

  12. 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

  13. SAN function Recovery interval Time = 30 sec A 550 400 HRA S1 SCL= 450 msec SNRT= 550 msec CSNRT= 150 msec

  14. SAN function Idea: reset the SAN – Narula method 8 paced beats 580 S1 A Recovery interval= time of paced beat penetrates & resets SAN+SCL+time for spont. Beat to exit SAN = SCL+ 2 SACT

  15. Assessment of AVN function • Pacing: site type (burst –ramp) Extrastimulation (site – number- coupling intervals) Differentiation (atrial- ventricular)

  16. Atrial pacing Pacing interval S1 A V A V

  17. V pacing A V V A

  18. Tests of AVN function • Antegrade 1:1 AV conduction • Antegrade WCL • Retrograde 1:1 VA conduction • Retrograde WCL • AVN/ERP

  19. 1:1 AV cond. A V

  20. AVN/ERP S1 S2 400/350

  21. 1:1 VA cond. Retrograde sequence of activation V A PCL= 300 msec

  22. VA dissociation A A V V V PCL=260 msec

  23. V. extrastim S1 S2 S

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