Rhythm Disorders Flashcards
When is digoxin given for AF?
It’s 2nd line if non-paroxysmal and sedentary
Carbimazole for hyperthyroidism needs to be promptly stopped when?
If the pt has signs of infection, take bloods. If low WCC (bc can cause agranulocytosis and neutropenia) need to stop the carbimazole ASAP
Give some common causes of bradycardia
- Physiological (sleep, athletes)
- Cardiac (AV block, sinus node disease)
- Non-cardia (vasovagal, hypothermia, hypothyroidism, hyperkalaemia)
- Drugs (B-blockers, diltiazem, digoxin, amiodarone)
What’s given for chemical cardioversion? When is it given for AF?
Given only after 3w of anticoagulation (if not acutely unwell)
- Anti-arrhythmic e.g. flecainide, amiodarone (If structural / IHD -> amiodarone) (300mg IV over 20-60 mins followed by 900mg infusion over 24hrs)
- Give a rate-control drug at the same time (Beta-blocker e.g. bisoprolol, metoprolol, esmolol, carvedilol (not sotalol), or rate limiting CCB e.g. diltiazem or verapamil (NOT CCB if HF w/ reduced EF)
If you’ve given someone cardioversion, what anticoagulation do you give them?
- Start anticoagulation w/ heparin or enoxaparin pre-cardioversion
- Then continue a DOAC for >4w if have been in AF for >24hrs e.g. rivaroxaban, apixaban, edoxaban, dabigatran, warfarin
- After 4w, decide about continuation using CHA2DS2VASc
What is involved in the CHADVASC score?
CHA₂DS₂-VASc
- CHF
- BP >140/90 or current antihypertensives
- Age > 75yo (2 points)
- DM
- Stroke, TIA (2 points)
- Vascular disease (MI, PAD, aortic plaque)
- Age 65-74
- Sex (female)
How do you manage bradycardias which are “unstable” (shock, syncope, myocardial ischaemia, HF)?
- Treat the cause
- 500mcg IV atropine every 3-5 mins up to 3mg (i.e. 6 times) (unless cardiac transplant, and beware in MI)
- Then can consider 2nd line drugs or proceed to transcutaneous pacing
Which peri-arrest rhythms are adenosine given for? What dose
Regular narrow-complex tachycardias (sinus tachycardia, paroxysmal SVT (AVNRT, AVRT (WPW)), atrial flutter w/ regular AV conduction
Vagal manoeuvres -> 6mg adenosine as rapid IV bolus -> 12mg adenosine -> 12mg adenosine
What CHA2DS2VASc score indicates the need for anticoagulation?
> 2 in females or >1 in men
Give an example of an anticoagulant and dose used for AF
DOAC e.g. 20mg rivaroxaban od
Which peri-arrest rhythms do you shock?
Tachycardias which are “unstable” i.e. shock, syncope, myocardial ischaemia, HF
What rate control is given for AF if they fail to respond to one drug?
Can combine 2 of BB, diltiazem and digoxin if no improvement
Beta-blocker e.g. bisoprolol, metoprolol, esmolol, carvedilol (not sotalol)
When given DC electrical cardioversion, what drugs need to be given at the same time?
- Anaesthetic drugs
- Start anticoagulation pre-cardioversion (heparin/enoxaparin) or continue their current anticoagulation
What scoring systems are used to decide on giving anticoagulation in AF?
o CHA2DS2VASc
o HAS-BLED
What rate control is given for AF?
AV nodal blocking drugs:
• Beta-blocker e.g. bisoprolol, metoprolol, esmolol, carvedilol (not sotalol)
• Rate limiting CCB e.g. diltiazem or verapamil (NOT if HF w/ reduced EF)
Which peri-arrest rhythms respond to vagal manoeuvres?
Regular narrow-complex tachycardias (sinus tachycardia, paroxysmal SVT (AVNRT, AVRT (WPW)), atrial flutter w/ regular AV conduction
What is involved in the HAS-BLED score?
- HTN >160
- Harmful alcohol
- Abnormal liver function
- Abnormal renal function
- Stroke
- Bleeding Hx or predisposition
- Labile INR
- Elderly >65yo
- Drugs (antiplatelets, NSAIDs)
When may atropine be CI for bradycardias? What can you give instead?
BEWARE in acute myocardial ischaemia / MI bc may cause worsening ischaemia
AVOID if cardiac transplant
Consider 100-200mg theophylline by slow IV injection if acute inferior MI, spinal cord injury or cardiac transplant
Consider proceeding straight to transcutaneous pacing
When starting warfarin, what else do you start and why?
Start unfractionated heparin / LMWH at same time, until INR 2.0-3.0
How are peri-arrest tachycardias classified? Give examples of each
Narrow-complex (<0.12s / 3 small squares):
- Regular: sinus tachy, paroxysmal SVT (AVNRT, AVRT (WPW)), atrial flutter w/ regular AV conduction
- Irregular: AF, or atrial flutter w/ variable AV conduction
Broad-complex:
- Regular: VT (or SVT w/ BBB)
- Irregular: AF w/ BBB, AF w/ WPW, polymorphic VT (torsade de pointes)
What can be given for bradycardia?
IV atropine or isoprenaline
500mcg IV atropine - repeat every 3-5 mins up to 3mg (i.e. 6 times)
What can be given for bradycardias caused by acute inferior MI, spinal cord injury or cardiac transplant?
100-200mg theophylline
What anticoagulation is given for AF longterm?
DOAC: apixaban, dabigatran, rivaroxaban, or vit K antagonist
What J of cardioversion do you use when?
o Cardiovert w/ 120-150J if broad-complex tachycardia or AF
o Cardiovert w/ 70-120J if narrow-complex tachycardia or atrial flutter
How is VT treated?
300mg IV amiodarone over 20-60 mins, followed by 900mg infusion over 24hrs
What doses of amiodarone are given for peri-arrest rhythms?
Loading dose of 300mg IV over 20mins, followed by a 900mg infusion over 24hrs if:
- Unstable tachycardia (shock, syncope, myocardial ischaemia, HF)
- AF
- VT
How do you treat an unstable (shock/syncope/MI/HF) tachycardia?
DC cardioversion (up to 3 times) -> still unstable? -> amiodarone and re-attempt cardioversion
o Can also do vagal manoeuvres if regular narrow complex tachycardia
o Cardiovert w/ 120-150J if broad-complex tachycardia or AF
o Cardiovert w/ 70-120J if narrow-complex tachycardia or atrial flutter
o Give amiodarone as a loading dose of 300mg IV over 10-20mins, followed by a 900mg infusion over 24hrs
How are regular narrow-complex tachycardias managed?
Vagal manoeuvres -> 6mg adenosine as rapid IV bolus -> 12mg adenosine -> 12mg adenosine
o Carotid sinus massage, Valsalva manoeuvre
o Adenosine quickly through large cannula, may cause chest discomfort
o These steps should almost always terminate AVNRT/AVRT (check for signs of atrial flutter)
Give an examples of a rate-control drug and dose used in AF
Beta-blocker e.g. bisoprolol 1.25mg od
