Ventricular arrhythmias

RMC

1. BY
DR SHAWANA SAJJAD
Ventricular
Tachyarrhythmias

2. Module Objectives –
Ventricular Tachyarrhythmias
•Differentiate types of ventricular
tachycardias using ECG
After completion of this module,
the participant should be able to:

3. Module Outline –
Ventricular Tachyarrhythmias
I.Description
II.Characteristics
A.Mechanisms
B.Sustained vs. nonsustained
C.Premature ventricular contractions

4. Module Outline –
Ventricular Tachyarrhythmias
III.Classification
A.Monomorphic
1.Idiopathic
a.Description
b.ECG recognition
c.Treatment – ablation
2.Bundle branch
a.Description
b.ECG recognition
c.Treatment –ablation

5. Module Outline –
Ventricular Tachyarrhythmias
III.Classifications - continued
1.Ventricular flutter
a.ECG recognition
4.Ventricular fibrillation
a.ECG recognition
B.Polymorphic
1.Torsades de pointes
a.Description
b.ECG recognition

6. Ventricular Tachycardia (VT)
•Originates in the ventricles
•Can be life threatening
•Most patients have significant heart disease
–Coronary artery disease
–A previous myocardial infarction
–Cardiomyopathy

7. Mechanisms of VT
•Reentrant
–Reentry circuit (fast and slow pathway) is confined to
the ventricles and/or bundle branches
•Automatic
–Automatic focus occurs within the ventricles
•Triggered activity
–Early afterdepolarizations (phase 3)
–Delayed afterdepolarizations (phase 4)

8. Reentrant
•Reentrant ventricular arrhythmias
–Premature ventricular complexes
–Idiopathic left ventricular tachycardia
–Bundle branch reentry
–Ventricular tachycardia and fibrillation when
associated with chronic heart disease:
•Previous myocardial infarction
•Cardiomyopathy

9. Automatic
•Automatic ventricular arrhythmias
–Premature ventricular complexes
–Ischemic ventricular tachycardia
–Ventricular tachycardia and fibrillation when
associated with acute medical conditions:
•Acute myocardial infarction or ischemia
•Electrolyte and acid-base disturbances, hypoxemia
•Increased sympathetic tone

10. Automaticity
Abnormal Acceleration of Phase 4
Fogoros: Electrophysiologic Testing. 3
rd
ed. Blackwell Scientific 1999; 16.

11. Triggered
Fogoros: Electrophysiologic Testing. 3
rd
ed. Blackwell Scientific 1999; 158.

12. Sustained vs. Nonsustained
•Sustained VT
–Episodes last at least 30 seconds
–Commonly seen in adults with prior:
•Myocardial infarction
•Chronic coronary artery disease
•Dilated cardiomyopathy
•Non-sustained VT
–Episodes last at least 6 beats but < 30 seconds

13. Premature Ventricular
Contraction
•PVC
–Ectopic beat in the ventricle that can occur singly
or in clusters
–Caused by electrical irritability
•Factors influencing electrical irritability
–Ischemia
–Electrolyte imbalances
–Drug intoxication

14. Classification
•Ventricular Tachycardia
–Monomorphic
•Idiopathic VT
•Bundle branch reentry tachycardia
•Ventricular flutter
•Ventricular fibrillation
–Polymorphic
•Torsades de pointes (TdP)

15. Monomorphic VTs

16. Monomorphic VT
•Heart rate: 100 bpm or greater
•Rhythm: Regular
•Mechanism
–Reentry
–Abnormal automaticity
–Triggered activity
•Recognition
–Broad QRS
–Stable and uniform beat-to-beat appearance

17. ECG Recognition
ECG used with permission of Dr. Brian Olshansky.

18. Distinguishing wide complex SVT
from ventricular tachycardia
In VENTRICULAR TACHYCARDIA
•H/O coronary disease or infarction
•QRS width >0.14 sec
•AV dissociation showing capture or fusion beats
•Extreme right axis deviation
•Q wave in V6

19. The Brugada Criteria
Table I.
Diagnosis Of Wide QRS Complex Tachycardia With A Regular Rhythm
Step 1. Is there absence of an RS complex in all precordial leads V1 – V6?
If yes, then the rhythm is VT.
· Sens 0.21 Spec 1.0
Step 2. Is the interval from the onset of the R wave to the nadir of the S
wave greater than 100 msec in any precordial leads?
If yes, then the rhythm is VT.
· Sens 0.66 Spec 0.98
Step 3. Is there AV dissociation?
If yes, then the rhythm is VT.
· Sens 0.82 Spec 0.98
Step 4. Are morphology criteria for VT present? See Table II.
If yes, then the rhythm is VT.
· Sens 0.99 Spec 0.97

20. Morphology Criteria for VT
Table II.
Morphology Criteria for VT
Right bundle type requires waveform from both V1 and V6.
V1 V6
Monophasic R wave QS or QR
QR or RS R/S <1
Left bundle type requires any of the below morphologies.
V1or V2 V6
R wave > 30 msec
Notched downstroke
S wave.
Greater than 60msec
nadir S wave.
QR or QS
Adapted from Brugada et al. A new approach to the differential diagnosis of regular tachycardia with a wide QRS complex.
Circulation 1991; 83:1649-59.

21. Idiopathic Right
Ventricular Tachycardia
•Right ventricular idiopathic VT
–Focus originates within the right ventricular
outflow tract
–Ventricular function is usually normal
–Usually LBBB, inferior axis
•Treatment options:
–Pharmacologic therapy (beta blockers, verapamil)
–RF ablation

22. Kay NG. Am J Med 1996; 100: 344-356.
ECG Recognition

23. Case History: Idiopathic VT
•First episode
–9 hours of palpitations
–In ER, found to be in wide-complex tachycardia of
LBBB, inferior axis, at 205 bpm
–Converted with IV lidocaine; placed on tenormin
•Second episode
–While on tenormin, patient had onset of palpitations
at airport
–In ER, converted with IV lidocaine
•Patient underwent EP study
39 y.o. female with no prior cardiac history

24. Case History: Idiopathic VT
•At EP study, tachycardia focus was mapped
and localized to right ventricular outflow tract
•The focus was successfully ablated
using radiofrequency energy, with no
subsequent inducible or clinical VT

25. Idiopathic Left
Ventricular Tachycardia
•RBBB
–Involves the Purkinje network
•Treatment options:
–RF ablation
–Pharmacologic therapy (verapamil, beta blockers)

26. ECG used with permission of Kay NG.
ECG Recognition

27. Bundle Branch Reentry
•Reentry circuit is confined to the left and right
bundle branches
•Usually LBBB, during sinus rhythm
•Presents with:
–Syncope
–Palpitations
–Sudden cardiac death
•Treatment: RF ablation of right bundle

28. VT Due to Bundle
Branch Reentry

29. Ventricular Flutter
•Heart rate: 300 bpm
•Rhythm: Regular and uniform
•Mechanism: Reentry
•Recognition:
–No isoelectric interval
–No visible T wave
–Degenerates to ventricular fibrillation
•Treatment: Cardioversion

30. Ventricular Fibrillation
•Heart rate: Chaotic, random and asynchronous
•Rhythm: Irregular
•Mechanism: Multiple wavelets of reentry
•Recognition:
–No discrete QRS complexes
•Treatment:
–Defibrillation

31. ECG Recognition
•P waves and QRS complexes not present
•Heart rhythm highly irregular
•Heart rate not defined

32. Polymorphic VT

33. Polymorphic VT
•Heart rate: Variable
•Rhythm: Irregular
•Mechanism:
–Reentry
–Triggered activity
•Recognition:
–Wide QRS with phasic variation
–Torsades de pointes

34. ECG Recognition
EGM used with permission of Texas Cardiac Arrhythmia, P.A.

35. Torsades de Pointes (TdP)
•Heart rate: 200 - 250 bpm
•Rhythm: Irregular
•Recognition:
–Long QT interval
–Wide QRS
–Continuously changing QRS morphology

36. Mechanism
•Events leading to TdP are:
–Hypokalemia
–Prolongation of the action potential duration
–Early afterdepolarizations
–Critically slow conduction that contributes to reentry

37. ECG Recognition
•QRS morphology continuously changes
•Complexes alternates from positive to negative

38. A 67 year old male with history of previous infarct and
reduced LV function presents with palpitations and dizziness.
His blood pressure is 80/40. The appropriate next step is ?
•A. Synchronized cardioversion for VT
•B. I.V. Procainamide for Atrial Fibrillation with
WPW syndrome
•C. Synchronized cardioversion for unstable SVT
with aberrancy.
•D. I.V. Amiodarone for SVT with aberrancy in a
patient with reduced LV function.

40. Answer A.
•This patient has ventricular tachycardia. An RS
interval of greater than 100 msec is clearly visible.
In addition, by history this patient is
overwhelmingly likely to present with VT with a
wide complex rhythm. Also this patient is not
stable with relative hypotension requiring
immediate cardioversion as opposed to
pharmacologic therapy.

41. A 46 year old female is admitted with dizziness. She is
an alcoholic, on methadone, with schizophrenia. She
began feeling dizzy after starting a fluoroquinalone for a
UTI. Which of the following should be your next step?
•A. Administer I.V . Procainamide
•B. Consult E.P. for placement of a defibrillator
•C. Discontinue antibiotic, treat with I.V. magnesium, discontinue
antipsychotic, and consider temporary pacing
•D. Administer I.V. amiodarone because it is unlikely cause
Torsades de Pointes.

43. Answer C.
•This patient has Torsades de Pointes with classic
polymorphic VT and prolonged QT demonstrated
in the bottom strip. Antipsychotics,
hypomagnesemia, quinolones all may predispose
to this arrhythmia. Procainamide or amiodarone
would worsen this rhythm. ICD is not indicated .

44. Thank
you!