ventricular tachycardias Flashcards
what are sustained ventricular tachycardia (>30sec)
A ventricular rhythm faster than 100 bpm lasting at least 30 seconds or requiring termination due to haemodynamic instability. VT is defined as a wide complex tachycardia (QRS 120 milliseconds or greater) that originates from one of the ventricles, and is not due to aberrant conduction (e.g., from bundle branch block)
what does sustained ventricular tachycardia cause
- pre syncope
- syncope
- hypotension
- cardiac arrest
what is the pulse rate typically of sustained ventricular tachycardia
120-220 bpm
what does the ECG of sustained ventricular tachycardia show
- rapid ventricular rhythm
- broad abnormal QRS complex
- visible P wave which appear to march through the tachycardia, capture beats and fusion beats
what are capture beats
an intermittent narrow QRS complex owing it to normal ventricular activation via the AV node and conducting system
what are fusion beats
intermediate between ventricular tachycardia beat and capture beat
what are symptoms of ventricular tachycardia
Dizziness Shortness of breath Lightheadedness Feeling as if your heart is racing (palpitations) Chest pain (angina)
Sustained and more-serious episodes of ventricular tachycardia may cause:
Loss of consciousness or fainting Cardiac arrest (sudden death)
how do you manage ventricular tachycardia
- haemodynamically compromised = emergency DC cardioversion
- haemodynamically stable = IV therapy with beta blockers, class 1 drugs or aminodarone
what is ventricular fibrillation
Ventricular fibrillation is a heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to quiver uselessly, instead of pumping blood
what can happen to a patient with ventricular fibrillation
the patient is pulseless and becomes rapidly unconscious; respiration ceases (cardiac arrest)
what does the ECG show in ventricular fibrillation
- Chaotic irregular deflections of varying amplitude
- No identifiable P waves, QRS complexes, or T waves
- Rate 150 to 500 per minute
- Amplitude decreases with duration (coarse VF -> fine VF)
what provokes ventricular fibrillation
ventricular ectopic beat
how do you treat ventricular fibrillation
electrical defibrillation
what is Brugadas syndrome
Brugada syndrome can cause the heart to beat dangerously fast. These unusually fast heartbeats – known as an arrhythmia – can sometimes be life threatening.
Brugada syndrome is usually caused by a faulty gene that’s inherited by a child from a parent. A simple heart test can be done to see if you have it.
what are symptoms of brugadas syndrome
- asymptomatic
- blackouts
- fits (seizures)
- occasional noticeable heartbeats (palpitations)
- chest pain
- breathlessness
- dizziness