1. Supraventricular Arrhythmias Mohamed Hamdan, MD Professor of Internal Medicine Director, Clinical Cardiac Electrophysiology

2. Definition • Rapid heart rhythm during which the electrical impulse propagates down the normal His Purkinje system similar to normal sinus rhythm • Distinct from ventricular tachycardia which only originates in the ventricles

3. Mechanisms of Arrhythmia • Automaticity • Enhanced automaticity • Abnormal automaticity

4. Mechanisms of Arrhythmia • Triggered Activity • Small depolarizations during or just after repolarization (phases 3 or 4) which can trigger a new depolarization.

5. Mechanisms of Arrhythmia • Reentry-most common mechanism • Short circuit that forms between two “pathways” that are either anatomically or functionally distinct • Typically: • Path 1: Slow conduction, short refractory period • Path 2: Rapid conduction, long refractory period

6. Reentry Panel A: Most impulses conduct down both pathways. Panel B: Unidirectional block, due to longer refractoriness in one pathway. Panel C: Potential to have reentry back up the previously refractory pathway Panel D: Reentry then can persist.

7. Supraventricular Arrhythmias • Atrial arrhythmias (AT, AFL and AF) • Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) • Atrioventricular reentrant tachycardia (AVRT) Wolf-Parkinson-White Syndrome • Orthodromic AVRT • Antidromic AVRT

8. SVT: Symptoms • May be variable • Palpitations, chest pounding, neck pounding • Weakness/malaise • Dyspnea • Chest pain • Lightheadedness • Near syncope/syncope • Symptoms usually abrupt in onset and termination • May have history of symptoms since childhood or have a positive FHx

9. SVT: Physical Exam • In absence of tachycardia, usually normal • Rapid heart rate (150-250) • May be irregular or regular (mechanism) • BP may be low or with narrow pulse pressure • Neck veins may reveal cannon waves.

10. Supraventricular Arrhythmias • Atrial arrhythmias (AT, AFL and AF) • Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) • Atrioventricular reentrant tachycardia (AVRT) Wolf-Parkinson-White Syndrome • Orthodromic AVRT • Antidromic AVRT

11. Originates in sinus node (automaticity) 50-100 bpm resting Up to 200 bpm Conduction through normal AV axis P wave morphology reflects site of onset Sinus Rhythm

12. Atrial Tachycardia • Ectopic atrial focus • Reentrant, automatic or triggered • 150-250 bpm • 1:1 AV conduction • Paroxysmal or “warm up” • P wave morphology variable

13. Focal Atrial Tachycardia RAA LAA SN * * * SVC IA S CT RAFW PV CSO LAFW IVC

14. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 20 yr woman with post-partum congestive heart failure

15. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 Adenosine Injection

16. I II III aVR aVL aVF V1 V2 V3 V4 V5 V6 Post- Adenosine Injection

17. CT CT MAP MAP CS CS His His Catheter location : Right atrial appendage LAO RAO

18. I II III aVL MAP dist MAP prox CT 1,2 CT 3,4 CT 5,6 CT 7,8 CT 9,10 CT 11,12 CT 13,14 CT 15,16 CS dist CS prox Earliest Atrial Activation : Right Atrial Appendage - 23 msec

19. I II III aVL MAP dist MAP prox CT 1,2 CT 3,4 CT 5,6 CT 7,8 CT 9,10 CT 11,12 CT 13,14 CT 15,16 CT 17,18 CT 19,20 CS dist CS prox Atrial Tachycardia Sinus Rhythm RF on 1.9 sec

20. Atrial Tachycardia: Inferior Crista Terminalis Atrial Tachycardia: Inferior Crista Terminalis V1 II aVL aVF Rove 1,2 Rove 3,4 CT 1,2 CT 3,4 CT 5,6 CT 7,8 CT 9,10 CT 13,14 CT 15,16 CT 17,18 CT 19,20 CS prox RV -38 ms

21. Scar Tricuspid Annulus II III V1 V6 RA Atrial Tachycardia Sinus Rhythm RF On ABL

22. Atrial Flutter • Reentrant circuit localized to the RA • 250-350 bpm • 2:1 or variable AV block • Classic “saw-tooth” P waves

23. Activation on Halo Catheter Activation on Halo Catheter Typical = Counterclockwise V1 II aVF TA 19,20 TA 1,2 TA 9,10 TA 3,4 TA 5,6 TA 7,8 TA 9,10 CS Os TA 1,2 TA 11,12 TA 13,14 TA 17,18 TA 19,20 CS Os

24. Activation on Halo Catheter Activation on Halo Catheter V1 II aVF TA 1,2 TA 3,4 TA 5,6 TA 7,8 TA 9,10 TA 11,12 TA 13,14 TA 17,18 19,20 CS Os Atypical = Clockwise TA 19,20 TA 9,10 CS Os TA 1,2

25. Atrial Fibrillation • Chaotic atrial rhythm due to multiple reentrant wavelets • 350-500 bpm • Ventricular rate irregular and rapid due to variable AV block • HTN, valvular dz., metabolic dz., CMP, EtOH

26. Atrial Fibrillation • The rapid atrial activity results in: • Increased risk of thrombus formation and stroke • Rapid and irregular ventricular rate • The treatment is aimed at: • Decreasing the risk of stroke (coumadin, ASA) • Decreasing the ventricular rate (beta-blockers, calcium channel blockers, digoxin) • Restoring the rhythm to sinus (drug therapy, catheter ablation, surgical Maze)

27. Atrial Fibrillation • Advantages of rhythm control: • Abolition of symptoms • Halting atrial enlargement • Improvement in left ventricular function and exercise capacity • Disadvantages of rhythm control: • Subjecting patients to drug therapy and/or procedure that might be associated with complications

28. Atrial FibrillationTreatment • In patients with minimal symptoms and normal left ventricular function: • Coumadin/ASA • Rate control (drugs, AVJ ablation + BV pacing) • In patients with significant symptoms and/or left ventricular dysfunction: • Coumadin/ASA • Rate control (drugs, AVJ ablation + BV pacing) • Rhythm control (anti-arrhytmic drugs, catheter ablation)

29. Drug Therapy to Maintain Sinus Rhythm in Patients with Recurrent Paroxysmal or Persistent Atrial FibrillationACC/AHA/ESC Guidelines Heart Disease No (or minimal) Yes Heart Failure CAD Hypertension FlecainidePropafenoneSotalol LVH greater than or equal to 1.4 cm Sotalol Amiodarone Dofetilide Amiodarone Dofetilide Yes No Amiodarone, Dofetilide Flecainide Propafenone Disopyramide Procainamide Quinidine Disopyramide Procainamide Quinidine Considernonpharmacologicaloptions Amiodarone Dofetilide Sotalol Amiodarone Fuster et al. J Am Coll Cardiol. 2001;38:1231-1265. Disopyramide, Procainamide, Quinidine

30. Atrial FibrillationCatheter Ablation Ablate PV potentials PV Isolation Pappone (circumferential LA ablation)

31. Supraventricular Arrhythmias • Atrial arrhythmias (AT, AFL and AF) • Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) • Wolf-Parkinson-White Syndrome • Orthodromic AVRT • Antidromic AVRT • Atrial fibrillation with preexcitation

32. AV Nodal Reentrant Tachycardia Morphology and location of P wave relative to QRS distinct

33. 27 y.o with palpitations

34. Pseudo R’ in V1 during tachycardia NSR AVNRT

35. Junctional Ectopic Tachycardia

36. Normal sinus rhythm Junctional tachycardia

37. Supraventricular Arrhythmias • Atrial arrhythmias (AT, AFL and AF) • Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) • Atrioventricular reentrant tachycardia (AVRT) Wolf-Parkinson-White Syndrome • Orthodromic AVRT • Antidromic AVRT

38. Wolff-Parkinson-White Syndrome • Second electrical connection exists between the atria and ventricles (accessory pathway) • Resemble atrial tissue • Results in a short PR and • Delta wave (pre-excitation) • Some AP conducts only retrograde (concealed)

39. Arrythmias in WPW • The most common arrhythmia is orthodromic AV reentrant tachycardia (narrow QRS) • Less common are pre-excited tachcyardias (wide QRS) • Antidromic AV reentrant tachycardia • Atrial tachycardia/flutter with pre-excitation • AVNRT with pre-excitation • Atrial fibrillation with pre-excitation (most life threatening due to rapid ventricular response)

40. Orthodromic AVRT Conduction down AV axis during tachycardia gives NARROW QRS complex

41. Pre-excited Tachycardia Mechanisms AT AVRT AVNRT Conduction down AP during tachycardia gives WIDE QRS complex

42. Atrial Fibrillation

43. RF Ablation in WPW

44. Supraventricular Arrhythmias • Atrial arrhythmias (AT, AFL and AF) • Atrioventricular nodal reentrant tachycardia (AVNRT) and junctional ectopic tachycardia (JET) • Atrioventricular reentrant tachycardia (AVRT) Wolf-Parkinson-White Syndrome • Orthodromic AVRT • Antidromic AVRT

45. SUMMARY Mechanisms of SVT FP SP AVNRT Atrial Tachycardia AVRT

46. Short RP AVRT AT Slow-Slow AVNRT Long RP AT Atypical AVNRT PJRT Differential Diagnosis of NCT • P buried in QRS • Typical AVNRT • AT • JET

47. SUMMARY • Obtain a 12 lead ECG. The location of the P wave will dictate the differential diagnosis • If hemodynamically unstable (chest pain, heart failure, hypotension) CARDIOVERSION • If hemodynamically stable AV NODAL AGENT • Long term therapy depends on mechanism and can be conservative, pharmacologic or invasive • EP study often needed for definitive characterization of mechanism and can cure most SVTs with 90% success rate