Ventricular tachycardia (CVS)

Question 1

Define ventricular tachycardia

Answer 1

Ventricular tachycardia (VT) is a regular broad-complex tachycardia originating from a ventricular ectopic focus.

Question 2

What is a broad complex tachycardia?

Answer 2

Arrhythmias that have a heart rate greater than 100bpm and a QRS complex that is greater than 120ms.

Question 3

What are the features of VT on an ECG?

Answer 3

Tachycardia (>beats per minute), absent P waves,
Can be with or without a pulse (without is an emergency)

Question 4

What are the two types of VT - describe difference?

Answer 4

Monomorphic ventricular tachycardia - all QRS complexes have same shape and size
Polymorphic ventricular tachycardia - different QRS complexes

Question 5

What is torsades de pointes?

Answer 5

A type of polymorphic ventricular tachycardia, caused by prolongation of the QT interval

Question 6

What is monomorphic VT commonly caused by?

Answer 6

Myocardial infarction (due to causing scarring)

Question 7

What are the causes of VT?

Answer 7

IHD, structural heart disease e.g. cardiomyopathy, electrolyte imbalances, Drugs that cause QT prolongation

Question 8

Describe aetiology/development of ventricular tachycardia?

Answer 8

Most common mechanism is a re-entrant circuit - usually due to the scarring caused by MI

Question 9

What are the clinical features/symptoms of VT?

Answer 9

Haemodynamically stable pts may present with no symptoms, palpitations, dizzyness, light headed, shortness of breath, chest pain

Unstable pts may present with same as above and severe hypotension, severe dyspnea, dizzy, syncope and can lead to cardiac arrest

Question 10

What are the investigations/diagnostic criteria for VT?

Answer 10

ECG - diagnostic criteria is having tachycardia (>100bpm), absent p waves, broad QRS complex (>120ms)
It may also show the cause and type e.g. if mono/polymorphic
- also, electrolytes, transthoracic echo

Question 11

What are the differentials of VT?

Answer 11

SVT w/ aberrancy (bund branch block) or pre excitation, AFib, Aflutter, sepsis
diagnosed once done ecg tho

Question 12

What is the immediate management of pulsed VT with adverse features?

Answer 12

Adverse features = shock, syncope, chest pain, or heart failure
Immediate synchronised DC cardioversion (up to 3 attempts)

Question 13

What is the immediate management of pulsed VT with no adverse features?

Answer 13

Anti arrhythmics e.g. IV amiodarone

If the drugs fail then synchronised DC cardioversion (up to 3 attempts)

Question 14

What are the complications of VT?

Answer 14

It can lead to Vfib - pulseless, irregular broad complex tachycardia
ECG shows fibrillation waves - no identifiable p waves, QRS complexes or T waves
Has a very chaotic rhythm and rate

Question 15

What is emergency presentation of VT?

Answer 15

A pulseless VT - form of cardiac arrest so emergency
As they are haemodynamically unstable pts so show severe hypotension, severe dyspnea, chest pain, dizzy, syncope

Question 16

What is the emergency management of pulseless VT?

Answer 16

If pulseless VT = cardiac arrest emergency and a shockable rhythm
So requires 200J bi phasic unsynchronised shocks (aka defib),
After 3rd shock, 1mg/10ml IV adrenaline and 300mg IV amiodarone should be given. Then repeated adrenaline every 3-5 mins

Question 17

What is long term treatment for VT?

Answer 17

Anti arrhythmics e.g. amiodarone (but NOT verapamil)

Implantable cardioverter defibrillators aka ICD (esp for impaired LV function)