ventricular arrhythmias Flashcards
what are the main VAs? 5
ventricular tachyarrhythmias
- torsades des pointes
- ventricular fibrillation
- premature ventricular complex
- asystole
what does TdP look like on an ECG?
like VF but it is actually VT with varying axis
- there is a broad QRS complex and continuously changing QRS morphology
is the rhythm regular or irregulaar in TdP?
irregular
what may be the events leading to TdP?
- hypokalaemia
- prolongation of the action potential (drug induced)
- renal impairment (increased drug levels)
what does PVC look like on ecg?
very borad QRS
There is a fall in ___ following the ectopic beat - the patient might feel light headed
There is a fall in BP following the ectopic beat - the patient might feel light headed
what are some of the causes of PVC?
- Ischaemic heart disease,
- hypertension with left ventricular hypertrophy
- heart failure
- May be marker for inherited arrhythmia syndromes e.g. cardiomyopathy
if PVC worse on ______, need to investigate further
If worse on exercise, need to investigate further
what drugs are used in the treatment of PVC?
b blockers
most patients who get VT have significant heart disease , such as….
- coronary artery disease
- previous MI
what are the rare causes of VT?
- cardiomyopathy
- inherited/ familial syndromes
give some examples of inherited/familial arrhythmia syndrome that can cause VT?
long QT
brugada syndrome
what is the difference between monomorphic and polymorphic VT?
monomorphic - the qrs stay relatively stable
why do the QRS stay relatively stable in monomorphic VT?
each ventricular impulse is being generated from the same place in the ventricles
monomorphic VT is usually due to ______
scarring
polymorphic VT is usually due to ______ _ _______
TdP
what is VF?
a chaotic ventricular electrical activity which causes the heart to lose the ability to function as a pump
what is the treatment for VF?
- DC cardioversion
- cardiopulmonary resuscitation
what is the abnormilty in conduction in brugada syndrome?
there are faulty sodium channels which predispose to fatal arrhythmias
which group of people typically get brugada?
young males
what can trigger brugada?
fever
how do you prevent the arrhythmias caused by brugada if you know someone has it?
ICD
how do you manage acute long QT syndrome?
- correct any electrolyte disturbance
- stop causative drugs
- heart rate maintaed with atrial or ventricular pacing
- IV isoprenaline when QT prolongation is acquired
when do you not use isoprenaline in treatment of long QT?
when QT prolongation is congenital
what is the long term management of long QT?
- beta blockers
- left cardiac sympathetic denervation
- pacemaker therapy
what are the causes of VT and VF?
- mainly due to structural heart disease
- can be primary electrical disease though
what is the treatment for acute VT?
- dc cardioversion if unstable
acute CV only if it is an emergency - if stable consider pharmcologic cardioversion with AAD
- consider adenosine to make a diagnosis
what may be the causes of VT?
- electrolyte- hypokalaemia hypomagnesaemia
- ischaemia
- hypoxia
- medications that prolong the QT interval
which medications may prolong the QT interval?
sotalol. quinidine, terfenadine, erythromycin, digoxin
what are the treatment steps according to cheese and onion? part 1
- Give high-flow oxygen by face mask.
- Obtain IV access. Send U&E, cardiac enzymes, Ca2+, Mg2+. Correct low K+or Mg2+.
- Obtain 12-lead ECG.
- ABG (if evidence of pulmonary oedema, reduced conscious level, sepsis).
- Amiodarone IVI. Phlebitis may result if peripheral line used, especially if concentration >2mg/mL. Rarely, lidocaine 50mg over 2min instead, followed by infusion; see BNF.
what are the treatment steps according to cheese and onion? part 2
If polymorphic (torsade de pointes) magnesium sulphate 2g over 5min.
If this fails, or if cardiac arrest, use DC shock (p806 and inside back cover).
After correction of VT, establish the cause from history/investigations.
Maintenance antiarrhythmic therapy may be required, eg amiodarone.
Prevention of recurrent VT: implantation of automatic defibrillators (ICD) may help.
In refractory cases radiofrequency ventricular tachycardia ablation may be tried.
what is the treatment of VT long term?
- correct ischaemia - revascularisation
- ICD if life threatening
what is the indication for AADs in VT long term-
not so great
what is the function of ICD in the ventricle?
VT prevention, antitachycardia pacing, cardioversion, defibrillation
what is the function of ICD in the ventricle and atria ?
bradycardia sensing
bradycardia pacing
