Ventricular Tachycardia

Question 1

VT= broad complex tachycardia originating in ventricles

• HR > 100
• QRS > 120 ms

Answer 1

Classification:

1. Morphology
   - monomorphic
   - polymorphic
   - Torsades de pointe- polymorphic with QT prolongation
   - RV outflow tract tachycardia
   - Fasicular tachycardia
   - bidirectional VT
   - Ventricular flutter
   - Ventricular fibrillation
2. Duration
   - sustained: > 30 sec or requiring intervention due to haemodynamic compromise
   - non sustained: 3 or more consecutive ventricular complexes terminating spontaneously < 30 sec
3. Clinical presentation
   - haemodynamically stable
   - haemodyanmically unstable

Question 2

ECG Features suggestive of VT

Answer 2

• Rate > 100
• Rhythm: AV dissociation
• Rhythm: fusion & capture beats
• extreme axis deviation: QRS + aVR & - in I & aVF
• QRS: > 160ms very broad
• absence of typical LBBB or RBBB
• concordance precordial leads
• Brugadas signs: distance onset QRS to nadir S wave > 100ms
• josephsons sign: notching near nadir S wave
• RSR’ complex taller L rabbit ear

Question 3

Clinical features VT:

Answer 3

age > 35
structural heart disease
Ischaemic heart disese
privous MI
Congestive heart failure
cardiomyopathy
Family hx:
-sudden cardiac death
-HOCM
-Congenital long QT
-Brugada syndrome
-Arrhythmogenic RV dysplasia

Question 4

Monomorphic VT

Answer 4

Regular rhythm
originates from single focus within ventricles
Produces uniform QRS complexes within each lead

Question 5

Monomorphic VT: CAUSES

Answer 5

Ischaemia
Dilated cardiomyopathy
hypertrophic cardiomyopathy
Chagas disease

Question 6

Polymorphic VT

Answer 6

multiple ventricular foci
QRS complex varying amplitude, axis & duration
Cause: ischaemia

Question 7

Torsades De Pointe

Answer 7

Polymorphic VT in context of QT prolongation
QRS complex twist around isoelectric point
short lived
degenrate into VF
CAUSES
- drug: prolong QT
-electrolyte: hypokalemia, hypomagnesemia
-medical conditon

Question 8

Causes of prolonged QT

Answer 8

Antipsychotic
-amisulpride
-chlorpromazine
-droperidol
-haloperidol
-Olanzapine
-Quetiapine
Class 1A antidysrhythmic
-quinidine
-procainamide
Class 1C antidysrhythmic
- flecanide
Class III antidysrhythmic agent
-sotalol
TCA
-amitriptyline 
-doxepin
Other antidepressants
-citalopram
-escitalopram
-bupropion
-moclobomide
Antihistamine
-loratadine
Antimalarial
-chloroquine
-hydroxychloroquine
-quinine
Antibacterial
-macrolides
-erythormycin
Antifungal
-azols
Methadone