1. Cardiac Electrophysiology & Ablation
Electrophysiology study
Cardiac Ablation
Arrhythmias for ablation
Supra-ventricular tachycardia
Wolff-Parkinson White
Atrial Flutter
Atrial Fibrillation
Atrial Tachycardia
Ventricular Tachycardia
Helen Eftekhari : Arrhythmia Nurse

2. THE HEART’S INTRINSIC CONDUCTION SYSTEM 1)Sino-Atrial node spreads depolarization wave across atria 2) Electrical Impulses collect at the atrio-ventricular node 3)Sends signals down conduction pathways depolarizing the ventricles.

3. Electrophysiology Study
Study for diagnosis of tachycardia – induce tachy
Recording of heart electrical activity
Wires placed in right atrium heart to pace & sense (via RFV)
Transeptal approach used to cross right atrium to left atrium
Intracardiac electrogram (ICegram) records electrical activity at precise locations.
3-D mapping systems: computer-generated image of cardiac chambers

4. Catheter Ablation Destruction of Tissue
Most Tachycardias depend on re-entry pathways (90%): can be focal
Can be “cured” by destruction of tissue
Energy source:
Radiofrequency energy: cells destroyed by heating > 50C
Cool-tip
Cryoablation: specialised ablation catheter - liquid nitrous oxide released
Complications: 1% permanent pacemaker, 1-2% cardiac
tamponade, groin haematoma, <1% thromboembolic risk,
Additional procedures: cardioversion, pericardiocentisis
Post Ablation conduction block is checked.

5. Regular Narrow Complex Tachycardia (RNCT) SVT (supraventricular tachycardia) HR bpm Sudden Onset / Terminated by vasovagal manouvers or adenosine Atrio-ventricular re-entry tachycardia (AVRT) Atrio-ventricular node re-entry tachycardia (AVNRT)

6. Supra-Ventricular Tachycardia (SVT)
Younger healthy people.
Atrio-ventricular groove tough tissue
Extra soft tissue (myocardial strands) = “Concealed” accessory pathway
Extra electrical connection atria & ventricles
Atrio-ventricular Re-entry tachycardia OR
Dual AV node pathways (AVNRT)
Slow pathway modification
70% middle aged women
Success 90 – 95% : Post RFA VA block confirmed / no inducible tachycardia

7. Pre-Excitation

8. Wolf-Parkinson White Syndrome
ECG : Revealed Pathway
short PR interval (less 120ms)
Slurring & slow rise of the QRS (delta wave)
Widened QRS Complex (>0.12 milliseconds)
Only ECG changes: WPW type ECG or pre-excitation
Plus Palpitations = WPW syndrome
ECG guides pathway location
EPS diagnostic of exact position
Manifest Accessory pathway: ability to conduct antegrade & retrograde
Success 90%
Post RFA success AV & VA block

9. WPWS & Atrial Fibrillation: Pre-Excited Atrial Fibrillation
WPW accessory pathways conduct from atria to ventricles
20-30% of patients with accessory pathways prone to Atrial Fibrillation
Not well understood why.
Some pathways can rapidly conduct.
Patients without a pathway who have atrial arrhythmias, the AV node acts as a brake.
WPW in AF with rapidly conducting pathway = bypasses AV node = exceedingly rapid ventricular response.
Diagnosis of Pre-excited Atrial Fibrillation is from ECG.
Needs Urgent attention: high risk of degenerating into VF
Fengler et al 2007, Gautam et el 2010)

10. Emergency Management Pre-excited AF this can increase conduction over pathway & high risk of VF
Anti-Arrhythmic Drugs to treat Pre-Excited Atrial Fibrillation
Class I: (1C class) Flecainide – usually the drug of choice
(1A class) Procainamide
Class III: amiodarone (to be used with caution) ibutilide
Adenosine should be used with caution – although it acts on the AV node, adenosine has an extremely short half-life
. Anti-Arrhythmic Drugs to Avoid in Pre-Excited Atrial Fibrillation (those which impede conduction via the AV node)
Class II: Beta-Blockers
Class IV Calcium Channel Blockers – Verapamil, Diltiazem Adenosine
Class V Digoxin 
ACC/AHA/ESC Guidelines 2003,Fengler et al 2007, Gautam et al 2010, Opie, L. Gersh, B. (2009) Drugs for the Heart. 7th Edition. Philadelphia, USA: Elsevier.

11. Which Arrhythmia?

12. Atrial Flutter – CTI Ablation
Macro-reentry circuit
Commonest form: typical anti-clockwise atrial flutter (70%)
Positive flutter waves V1; negative flutter waves in inferior leads
Re-entry circuit in right atrium, anticlockwise dependent on tissue called cavo-tricuspid isthmus.
CTI ablation.Anatomical procedure
Around 90% success. Bidirectional block confirmed
No transeptal approach stay on warfarin.
INR’s above 2 for 3 weeks pre

13. Advice Post EPS & RFA /CTI
Pre-Procedure stop anti-arrhythmics
Successful procedure do not restart
Aspirin / warfarin
Heart Rhythm advice
Groin Care
Chest discomfort
DVLA: 2 days – we recommend 1 week
Flying 1 month
Light activties within the 1st week- heavy activities 3-4 weeks

14. Which Arrhythmia?

15. Atrial Fibrillation – Pulmonary Vein Isolation
Single source of electrical waves
(pulmonary veins)
1-3 cm where myocardium fuses with pulmonary vein focus
Paroxysmal Atrial Fibrillation
Treatment for quality of life
Transeptal approach
70% success in paroxysmal A.F.
Success 50% if AF permanent.
Complex add lines w/ substrate
1% risk stroke, 1% pulmonary stenosis, 1% phrenic nerve injury, 1% cardiac tamponade, 1% PPM

16. Ablate & Pace strategy Symptomatic atrial fibrillation
Poor control w/ medical therapy
No further options
Implant permanent pacemaker
Ablate AV node – cannot conduct fast atrial rates
Poor percentage of biventricular pacing due to atrial fibrillation

17. Which Arrhythmia?

18. Atrial Tachycardia Lead V1, a negative or +/- P-wave was 100% specific for RA and a + or -/+ P-wave showed a sensitivity of 100% for an LA focus.
Foci in atria drives tachycardia
Difficult to ablate
Needle in Haystack
Complex mapping
often required

20. Which Arrhythmia?

21. Different Arrhythmia?

22. Normal Heart Ventricular Tachycardia
Right Ventricular Outflow Tract
LBBB positive inferior leads
Fascicular VT
RBBB negative inferior leads

23. Ventricular Tachycardia
Ventricular Tachycardia Ablation
VT in normal hearts: Types of VT with good success (90%) for ablation: RVOT & fascicular.
Very small numbers of patients with VT in structural heart disease are suitable for ablation.
VT STIM: ventricular stimulation:
EP study inducting ventricular tachycardia assess for ICD, VT ablation

24. Questions