Atrial fibrillation Flashcards
What is atrial fibrillation (AF)?
A condition where the electrical activity in the atria becomes disorganised, leading to fibrillation (random muscle twitching) of the atria and an irregularly irregular pulse.
What are the overall effects of atrial fibrillation?
Irregularly irregular ventricular contractions, tachycardia, heart failure due to impaired ventricular filling during diastole, increased risk of stroke.
What is the pathophysiology of atrial fibrillation?
Disorganised electrical activity in the atria overrides the normal sinoatrial node rhythm, causing uncoordinated, rapid, and irregular atrial contractions that pass through to the ventricles.
What are common causes of atrial fibrillation? (SMITH mnemonic)
- Sepsis
- Mitral valve pathology (stenosis or regurgitation)
- Ischaemic heart disease
- Thyrotoxicosis
- Hypertension
Alcohol and caffeine are lifestyle causes.
How may atrial fibrillation present in patients?
- Asymptomatic (incidental finding)
- Palpitations
- Shortness of breath
- Dizziness or syncope
- Symptoms of associated conditions (e.g., stroke, sepsis, or thyrotoxicosis)
What is the key examination finding in atrial fibrillation?
Irregularly irregular pulse.
What are the differential diagnoses for an irregularly irregular pulse?
- Atrial fibrillation
- Ventricular ectopics (disappear with exercise)
What are the ECG findings in atrial fibrillation?
- Absent P waves
- Narrow QRS complex tachycardia
- Irregularly irregular ventricular rhythm
What investigations may be required for atrial fibrillation?
- ECG
- Echocardiogram (for valvular heart disease, heart failure, or planned cardioversion)
What is paroxysmal atrial fibrillation?
AF episodes that recur and spontaneously resolve, lasting between 30 seconds and 48 hours.
What investigations may be used to assess paroxysmal atrial fibrillation?
- 24-hour ambulatory ECG (Holter monitor)
- Cardiac event recorder (1-2 weeks)
What is the treatment principle for atrial fibrillation?
- Rate or rhythm control
- Anticoagulation to prevent stroke
What is the first-line treatment for rate control in atrial fibrillation?
Beta blockers (e.g., bisoprolol).
What are the options for rhythm control in atrial fibrillation?
- Cardioversion (pharmacological or electrical)
- Long-term rhythm control (beta blockers, dronedarone, amiodarone)
What is immediate cardioversion used for?
- AF present for less than 48 hours
- Life-threatening haemodynamic instability
What anticoagulation treatment options are available for atrial fibrillation?
- Direct-acting oral anticoagulants (DOACs) first-line
- Warfarin second-line (if DOACs are contraindicated)
What is the CHA2DS2-VASc score used for?
Assessing whether a patient with atrial fibrillation should start anticoagulation to prevent stroke.
What factors are included in the CHA2DS2-VASc score?
- C – Congestive heart failure
- H – Hypertension
- A2 – Age above 75 (scores 2)
- D – Diabetes
- S2 – Stroke or TIA previously (scores 2)
- V – Vascular disease
- A – Age 65-74
- S – Sex (female)
What is the ORBIT score used for?
Assessing the risk of major bleeding in patients with atrial fibrillation on anticoagulation.
What are the factors in the ORBIT score?
- O – Older age (75 or above)
- R – Renal impairment (GFR <60)
- B – Bleeding history
- I – Iron deficiency (low haemoglobin or haematocrit)
- T – Taking antiplatelet medication
What is left atrial appendage occlusion?
A procedure for patients with contraindications to anticoagulation and high stroke risk, involving a catheter to block the left atrial appendage.
What is the target INR range for patients with atrial fibrillation on warfarin?
2 - 3.
What are direct-acting oral anticoagulants (DOACs)?
Oral anticoagulants that do not require INR monitoring, such as apixaban, edoxaban, rivaroxaban, and dabigatran.
What is the “pill-in-the-pocket” approach in paroxysmal atrial fibrillation?
A treatment where patients take a pill (usually flecainide) to terminate AF when symptoms start.
