Tachycardia

1. Narrow Complex &
Wide Complex Tachycardia
Department of Cardiology
Yangon General Hospital

2. General Approach

5. Supraventricular Tachycardias
Supraventricular - a rhythm process in which the
ventricles are activated from the atria or AV
node/His bundle region
 QRS typically narrow (in the absence of bundle
branch block)
 termed narrow QRS tachycardia
 regular rhythm (140-220 bpm)
 paroxysmal in nature

6. Presentation of PSVT
 Episodes of palpitation (sudden & abrupt onset)
with variable duration
 Pre-syncope, syncope, chest pain and abnormal
neck pulsation
 Urge to urinate (Atrial Natriuretic Peptide release)
 Rarely, Congestive Heart Failure and
Cardiomyopathy
 Dx based on symptom – rhythm correlation

7. Supraventricular Arrhythmias
 Atrial fibrillation
 Paroxysmal supraventricular tachycardias (PSVT)
 AV nodal reentry tachycardia (AVNRT)
 AV reentry tachycardia
 WPW Syndrome
 AV reentry over concealed bypass tract
 Atrial tachycardia

8. AVNRT
(retrograde P waves in I,II, V1 to V3)

9. Wolff-Parkinson-White Syndrome
(Short PR interval and Delta wave)

10. Orthodromic AVRT
Antidromic AVRT
Pre-excited AF

11. Atrial tachycardia

12. Atrial tachycardia
Termination with IV Adenosine

13. Atrial Flutter
(Saw-tooth shape P waves, negative in II,III, aVF)

14. Atrial Fibrillation
(loss of discernible P wave, irregular RR interval)

15. Acute Management of PSVT
 Vagotonic Maneuvers
 Carotid sinus massage
 Valsalva maneuver (bearing down)
 Facial ice pack (“diving reflex;” for kids)
 Increase the vagal tone, prolong AVN
refractoriness, terminate tachycardia
 Useful to clarify the underlying mechanism

16. Stimulation of carotid sinus triggers baroreceptor reflex and
increased vagal tone, affecting SA and AV nodes
Carotid Sinus Massage

17. Termination of SVT by Vagotonic Maneuver
(Carotid Sinus Massage)

18. Acute Management of PSVT
(pharmacologic intervention)
 IV Adenosine
 CCB: IV Verapamil ( if adenosine is
contraindicated and recurrent tachycardia)
 Elective cardioversion

19. Acute Management of PSVT
(pharmacologic intervention)
 IV Adenosine
 6 mg (max: 18 mg), short half life, rapid
administration, safe to use in pt with structural
heart d/s
 Caution: in patients taking Dipyridamole
 Contraindication: asthma & COPD
 Can terminate AVN dependent rhythm
 May terminate some types of AT
 Transient sensation of TOC, nausea and
flushing

20. SVT
Adenosine 6 mg
P P P P

21. Long-term treatment of PSVT
 AVN blocking agents: Verapamil, Diltiazem, β
blockers
(decrease frequency & severity, 30-60%)
 Class I: Flecainide, Propafenone (for WPW)
(prevented 80%, potential adverse effects)
 Class III: Sotalol, Amiodarone
(rarely indicated , potential toxicity for long-term use)
 Catheter ablation with using radiofrequency
energy ( refer to tertiary center )

22. Broad Complex Tachycardia & PSVT
 Preexisting BBB, intraventricular conduction
block
 Tachycardia contingent BBB : functional BBB or
rate related BBB
 Pre-excitation or conduction over AP (Antidromic
tachycardia & pre-excited AF)
 D/Dx - VT

23. Fusion activation
of the ventricles
“Delta” Wave
AP
PR < .12 s
QRS  .12 s
Sinus
beat
Hybrid
QRS shape
Accessory Pathway with Ventricular Pre-excitation
(Wolff-Parkinson-White Syndrome)

24. SVT with aberrancy

25. Pre-excited Atrial Fibrillation

26. Hallmarks of VT
 AV dissociation
 Capture and fusion beats
 Extreme axis deviation
 Atypical BB morphology, duration of QRS
 Precordial concordance
Rule of thumb
Broad complex tachycardia with CAD/ MI
considered as VT until proven otherwise

27. Ventricular Tachycardia
(LBBB with inferior axis)

28. Ventricular Tachycardia

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

30. Ventricular Fibrillation

31. Ventricular Fibrillation

32. 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

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

34. Torsades de Pointes (TdP)
Polymorphic VT
 Heart rate: 200 - 250 bpm
 Rhythm: Irregular
 Recognition:
 Long QT interval
 Wide QRS
 Continuously changing QRS morphology

35. ECG Recognition
 QRS morphology continuously changes
 Complexes alternates from positive to negative

36. Causes of Long QT interval
 Hypothyroidism
 Hypothermia
 Myocardial ischemia
 Increased ICP
 Electrolyte imbalance
 Hypokalaemia
 Hypocalcaemia
 hypomagnesaemia
 Congenital long QT syndrome

37. Causes of Long QT interval
Drugs :
 Macrolides : Erythromycin, Clarithromycin
 Quinidine
 Antifungals : Ketoconazole, Fluconazole
 Antipsychotics: haloperidol, amitriptyline,
chlorpromazine, risperidone
 Antinausea drugs: Ondansetron/granisetron,
Domperidone
 Methadone
 Anti-retrovirals : protease inhibitors
 Drugs used for MDRTB : Clofazimine (Cfz) ,
Bedaquiline (Bdq), Delamanid (Dlm) , Moxifloxacin
(Mfx), Levofloxacin (Lfx)

38. Treatment
 Pharmacologic therapy:
 Potassium
 Magnesium
 Isoproterenol
 Possibly class Ib drugs (lidocaine) to decrease
refractoriness/shorten length of action potential
 Overdrive ventricular pacing
 Cardioversion

39. The End