Ventricular tachycardia (CVS) Flashcards
Define ventricular tachycardia
Ventricular tachycardia (VT) is a regular broad-complex tachycardia originating from a ventricular ectopic focus.
What is a broad complex tachycardia?
Arrhythmias that have a heart rate greater than 100bpm and a QRS complex that is greater than 120ms.
What are the features of VT on an ECG?
Tachycardia (>beats per minute), absent P waves,
Can be with or without a pulse (without is an emergency)
What are the two types of VT - describe difference?
Monomorphic ventricular tachycardia - all QRS complexes have same shape and size
Polymorphic ventricular tachycardia - different QRS complexes
What is torsades de pointes?
A type of polymorphic ventricular tachycardia, caused by prolongation of the QT interval
What is monomorphic VT commonly caused by?
Myocardial infarction (due to causing scarring)
What are the causes of VT?
IHD, structural heart disease e.g. cardiomyopathy, electrolyte imbalances, Drugs that cause QT prolongation
Describe aetiology/development of ventricular tachycardia?
Most common mechanism is a re-entrant circuit - usually due to the scarring caused by MI
What are the clinical features/symptoms of VT?
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
What are the investigations/diagnostic criteria for VT?
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
What are the differentials of VT?
SVT w/ aberrancy (bund branch block) or pre excitation, AFib, Aflutter, sepsis
diagnosed once done ecg tho
What is the immediate management of pulsed VT with adverse features?
Adverse features = shock, syncope, chest pain, or heart failure
Immediate synchronised DC cardioversion (up to 3 attempts)
What is the immediate management of pulsed VT with no adverse features?
Anti arrhythmics e.g. IV amiodarone
If the drugs fail then synchronised DC cardioversion (up to 3 attempts)
What are the complications of VT?
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
What is emergency presentation of VT?
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
What is the emergency management of pulseless VT?
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
What is long term treatment for VT?
Anti arrhythmics e.g. amiodarone (but NOT verapamil)
Implantable cardioverter defibrillators aka ICD (esp for impaired LV function)
