Atrial Fibrillation Flashcards
What causes AF?
Disrupted electrical signals in the heart, causing an irregular heart beat
What are the 3 parameters which AF can be classified by?
- Heart rate - tachycardia/bradycardia
- Origin of electrical impulses - atria/ventricles
- Time
What are the 2 arrhythmias called which originate in the atria, and in the ventricles?
In the atria = supraventricular arrhythmia
In the ventricles = ventricular arrhythmia
What is absent on an ECG in an AF patient?
P wave, due to the disrupted depolarisation of the patients atria
What can cause AF?
Damage to heart
Drugs - caffeine, alcohol, thyroxine, B2 agonists
Non-cardiac causes - hyperthyroidism, acute infection
What is the tool used to measure someones bleeding risk?
HASBLED scoring system
Now some places are using the ORBIT tool
What is given to reverse the effects of warfarin?
K+ supplements
What is the CHA2DS2VASc tool? How do you interpret a patients score?
It measures a patients stroke risk.
1 point = no therapy/aspirin considered
>2 points = warfarin/DOAC given (high risk)
What types of drug classes should AF patients avoid?
NSAIDs
SSRIs
antiplatalets
These can all increase their bleeding risk while they are on anticoagulation therapy
What anticoagulants are given to AF patients to help reduce their stroke risk?
DOACs, e.g. apixaban, rivaroxiban, edoxaban
What is the treatment of rhythm control in AF?
Stable AF - flecainide (no IHD), or amiodarone (with IHD)
Unstable - DC shock given
What is the 1st line treatment for rate control in AF?
B-blocker
OR rate-limiting CCB, e.g. verapamil/diltiazem
Digoxin could also be given as monotherapy
Why should you never give a b-blocker with a CCB in AF?
Because it can increase the patients risk of a heart attack
What is the treatment for bradycardia?
Atropine 500mcg IV
What is the treatment for tachycardia?
Unstable - synchronised DC shock
Stable - adenosine 6mg IV
What monitoring is needed for AF?
INR (patient must be between 2-3)
Symptoms of AF
HR
ECG
What are the benefits of using a DOAC compared to warfarin?
Good safety
Fixed dosing regimen
Less interactions
What are the other alternative options of treatment for AF?
Class 1 - Na+ channel blockers
1A - quinidine, procainamide
1B - lidocaine, phenytoin
1C - flecainide
Class 2 - B-blockers
Class 3 - K+ channel blockers
Amiodarone, soltalol
Class 4 - Rate-limiting CCBs
Verapamil, diltiazem
Class 5 - adenosine, digoxin
What is the difference between dabigatran, and the other DOACs?
Dabigatran is the only direct thrombin inhibitor.
The rest are oral factor Xa inhibitors.
