Atrial Fibrillation Flashcards
What are the different types of AF
Paroxysmal
Persistent
Permanent
What is paroxysmal AF
Self-limiting
Less than 7 days
Recurs
What is persistent AF
Lasts over 7 days
Is not self-limiting
Cardioversion often attempted
May recur
What is permanent AF
Failed cardioversion
No further attempt to return to sinus rhythm
How do you manage paroxysmal AF
If rare and brief, it may be ignored
If frequent:-
Drugs to prevent episodes
Self-administered drugs to stop attacks after onset ("pill in the pocket")
Possible ablation if drugs ineffective
Anticoagulate if episodes continue
What drugs are used to prevent episodes of paroxysmal AF
Amiodarone
Sotalol
Propafenone
Flecainide
What are some side effects of amiodarone
Slate grey pigmentation of skin after exposure to sunlight
Abnormal LFTs
Lung fibrosis
Abnormally low BP
Many others
What drugs are used as “pill in the pocket”
Flecainide (most commonly)
Propafenone
How do you manage persistent AF
Attempt cardioversion
May have better outcomes if giving anti-arrhythmic drugs before and after cardioversion for 3-4 weeks
If arrhythmia is present for over 48 hrs, anticoagulation is necessary
For how long should you anticoagulate a patient with persistent AF
Around 3 weeks pre and post cardioversion
Long term if cardioversion is unsuccessful
What is cardioversion
Rhythm control
Can be DC (direct current) or pharmacological
What medications are used for pharmacological cardioversion
Flecainide
Amiodarone
In what cases is cardioversion unlikely to succeed
AF present for over a year
Valve disease
Poor LV function
Uncontrolled hypertension
What is rate control
Control of the ventricular rate to reduce symptoms
Can be used as an alternative to rhythm control if cardioversion contraindicated or patient
doesn’t want it
Used in permanent AF (failed cardioversion)
Delivered in combination with anticoagulation
What medication is used for rate control
Beta-blocker
Rate-limiting calcium channel blocker (eg. diltiazem, verapamil)
NEVER combine the two - can cause bradycardia
What is the problem with digoxin as a rate-controlling drug
It is good at controlling ventricular rate at rest, but not during exercise
What medication is used as anticoagulation in AF
Warfarin (LMWH as bridging agent)
NOAC (new oral anti-coagulant)
*Aspirin no longer used as not effective
What are the NOACs
Thrombin antagonist - dabigatran
Factor Xa antagonists - rivaroxaban, apixaban
*Doses more predictable than with warfarin, and fewer interactions
What is a downside of NOACs
They don’t have antidotes like warfarin (vit K)
Expensive
What is AF
Uncoordinated and disordered contraction of the atria at a fast rate, which leads to initiation of ventricular contraction at varying intervals
What is the major risk factor for AF
Age
What are some causes of AF
LONEly CHAV
Lone AF (no structural heart disase or cause found)
Coronary artery disease
Hypertension
Alcohol
Valvular heart disease (esp. mitral stenosis)
*Other acute medical conditions:- Infections/sepsis (esp. pneumonia) PE Thyrotoxicosis Non-cardiac surgery
What are the symptoms of AF
Often asymptomatic
Palpitations - if ventricular response is slow or fast
SOB, peripheral oedema and syncope - if a fast rate reduces ventricular filling
Chest pain - if coronary artery disease
What is seen on an ECG of a patient with AF
No P waves
Varying intervals between QRS complexes
How can paroxysmal AF be detected
Using a Holter monitor
What surgical options are available for AF
Pulmonary vein ablation
What is pulmonary vein ablation
Procedure carried out using a catheter inserted from the groin into the left atrium and into the ostia of the pulmonary veins
Stop ectopic beats travelling from the pulmonary veins from initiating AF
What is the CHA2DS2-VASc score
Calculates stroke risk for patients with AF
Congestive heart failure Hypertension (BP consistently over 140/90) Age over 75 (2 points) Diabetes mellitus Stroke or TIA or thromboembolism previously (2 points) Vascular disease Age 65-74 Sex category (ie. male or female)
Max score 9 - stroke risk 15%
What is the HAS-BLED score
Estimates risk of major bleeding for patients on anticoagulation for AF
Hypertension
Abnormal renal and liver function (1 point for each)
Stroke
Bleeding
Labile INRs (time in therapeutic range less than 60%)
Elderly - age over 65
Drugs or alcohol (1 point for alcohol, 1 point for medication predisposing to bleeding)
What are the common causes of AF?
Cardiovascular disease: HTN, HF and MI
Valvular: Mitral valve disease
Toxins: Alcohol-related heart disease
Infection (e.g. resp, urinary)
Iatrogenic: Post-surgical (especially cardiothoracic)
Endocrine: Thyrotoxicosis
What INR do you aim for in AF?
2-3
