1. Supraventricular Arrhythmias
Ira R. Friedlander, M.D.
8/26/14

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 ( )
May be irregular or regular (mechanism)
BP may be low or with narrow pulse pressure
Neck veins may reveal cannon waves.

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

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

12. Focal Atrial Tachycardia
CSO
IVC
RAFW
RAA
LAA
LAFW PV SN
I A S CT
* * *
SVC

13. 20 yr woman with post-partum congestive heart failureII
III
aVR
aVL
aVF V1 V2 V3 V4 V5 V6

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

15. Post- Adenosine InjectionII
III
aVR
aVL
aVF V1 V2 V3 V4 V5 V6

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

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

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

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

20. 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
CS Os
TA 9,10
TA 1,2
TA 11,12
TA 13,14
TA 17,18
TA 19,20
CS Os

21. Activation on Halo Catheter
Atypical = Clockwise II
aVF V1
CS Os
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
TA 19,20
TA 9,10
CS Os
TA 1,2

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

23. 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)

24. 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

25. Atrial Fibrillation Treatment
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:
Rhythm control (anti-arrhytmic drugs, catheter ablation)

26. Drug Therapy to Maintain Sinus Rhythm in Patients with Recurrent Paroxysmal or Persistent Atrial Fibrillation ACC/AHA/ESC Guidelines

27. Atrial Fibrillation Catheter Ablation
Ablate PV potentials PV Isolation Pappone
(circumferential LA ablation)

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

29. 27 y.o with palpitations
Does seeing the next ECG help you

30. Pseudo R’ in V1 during tachycardia
NSR
AVNRT

31. Junctional Ectopic Tachycardia

32. Normal sinus rhythm
Junctional tachycardia

33. 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)

34. 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)

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

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

37. Atrial Fibrillation

38. RF Ablation in WPW

39. SUMMARY Mechanisms of SVT Atrial Tachycardia AVNRT AVRT SP FP
Predictions about V:A time for DDX
Circuits require two pathways with different conduction vel and different refractory periods
Atrial Tachycardia
AVNRT
AVRT

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

41. 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