Peri-arrest arrhythmias Flashcards
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What are the two divisions of peri-arrest arrhythmias?
- arrhythmias that may lead to cardiac arrest
- arrhythmias that occur after initial resuscitation from cardiac arrest
What features indicate an arrhythmia is causing instability
- Shock
- syncope
- heart failure
- myocardial ischaemia
- extremes of heart rate
What is extreme tachycardia?
When heart rate increases, diastole is shortened to a greater degree than systole
What is extreme bradycardia?
Less than 40
What are the treatment options available for an arrhythmia?
- none
- vagal maneovures/percussion pacing
- pharmacological
- electrical
What should you remember to do after treating an arrhythmia?
Record an ECG
What could an unsynchronised shock cause?
Could co-incide with the T wave and cause VFib
What energy should be used in a broad-complex tachycardia needing shocked?
Start with 120-150J
What energy should you use for unstable AFib needing shocked?
maximum defib output
What energy is needed for atrial flutter and narrow complex tachycardia needing shocked?
70-120 J
What pad position should be used for AFib/flutter needing shocked?
AP
In a broad complex regular tachycardia treated with amiodarone, what are the next steps?
If successful then infusion of 900mg over 24h
What is an irregular broad-complex tachycardia most likely to be?
AF with BBB
How is TDP treated?
- stop all drugs that prolong the QT interval
- correct electrolyte abnormalities
- give mg 2g over 10 minutes
- get expert help
- if unstable features - shock
- If pulseless commence ALS
What are the different regular narrow complex tachycardias?
- sinus tachycardia
- paroxysmal SVT
- AF with regular AV conduction
What may the patient present like in paroxysmal SVT
usually benign unless structural heart disease, patient may have symptoms they find frightening
What is the atrial rate in atrial flutter?
About 300
What are the different vagal maneovres?
- carotid sinus massage
- valsalva
How effective are vagal maneovres?
They will terminate up to 1/4 of SVT
If vagal maneovres are not successful and the rhythm is not flutter what should you do?
Give adenosine 6mg
Why is a rapid narrow-complex pulseless tachycardia an exception to the ALS protocol?
Despite being PEA it is treatable by shock
In general, people who have been in AF for >48 hours should not be treated with cardioversion until they have been anticoagulated for how long?
3 weeks
unless trans-oesophageal echo has detected no evidence of thrombus
If the clinical situation indicates a patient who has been in AF requires urgent cardioversion what should you do?
Give LMWH in therapeutic dose or IV bolus of unfractionated heparin followed by an infusion to maintain the APTT at 1.5-2 times the reference control value
What are the contraindications of propafenone and flecainide?
Drugs used in chemical cardioversion of AF
- heart failure
- ihd
- left ventricular impairment
- prolonged QT
Which drugs should be avoided in cardioversion of pre-excited AF or A flutter and why?
- adenosine
- diltiazem
- verapamil
- digoxin
They may cause a relative increase in pre-excitation as they block the AV node
What are the cardiac causes of bradyarrhythmia?
AV block or sinus node disease
What are the non-cardiac causes of bradyarrhythmia
vasovagal, hypothermia, hypothyroidism, hyperkalaemia
What are the drug induced causes of bradyarrhythmia
beta-blockade, diltiazem, digoxin and amiodarone
What is usually the initial treatment in patients with adverse effects from a bradyarrhythmia?
Pharmacological
Pacing is used in those who have an ineffective/inadequate response and those at risk of asystole
What should you consider if beta-blockade or calcium-channel blockade is thought to be the cause of bradycardia?
consider giving IV glucagon
If digoxin is thought to be the cause of bradycardia- what should be done?
Consider use of digoxin specific antibody fragments
When should aminophylline be considered?
In bradycardia complicating;
* acute inferior wall infarction
* spinal cord injury
* cardiac transplantation
dose= 100-200mg by slow IV injection
Why should patients with cardiac transplants not be given atropine?
Hearts are denervated and will not respond to vagal blockade by atropine, which may cause paradoxical sinus arrest or high-grade AV block
What are the second line options for treatment of bradycardia?
- isoprenaline (starting at 5mcg per min)
- adrenaline (2-10mcg min)
- dopamine (2.5-10mcg kg min)
