Atrial Fibrillation

Question 1

What is atrial fibrillation?

Answer 1

Electrical activity in the atria t becomes disorganised, leading to fibrillation (random muscle twitching) of the atria and an irregularly irregular pulse

Question 2

Overall effects

Answer 2

Irregularly irregular ventricular contractions
Tachycardia (fast heart rate)
Heart failure due to impaired filling of the ventricles during diastole
Increased risk of stroke

Question 3

Pathophysiology

Answer 3

Normally, the sinoatrial node produces organised electrical activity that coordinates the contraction of the atria.

Atrial fibrillation occurs when this electrical activity is disorganised, causing the contraction of the atria to become uncoordinated, rapid and irregular.

Question 4

Common causes

Answer 4

S – Sepsis
M – Mitral valve pathology (stenosis or regurgitation)
I – Ischaemic heart disease
T – Thyrotoxicosis
H – Hypertension

Alcohol and caffeine are lifestyle causes worth remembering.

Question 5

Presentation

Answer 5

Patients are often asymptomatic, and atrial fibrillation is an incidental finding. It may be diagnosed after a stroke.

Patients may present with:

Palpitations
Shortness of breath
Dizziness or syncope (loss of consciousness)
Symptoms of associated conditions (e.g., stroke, sepsis or thyrotoxicosis)

Question 6

Key examination finding

Answer 6

Irregularly irregular pulse.

Question 7

ECG findings

Answer 7

Absent P waves
Narrow QRS complex tachycardia
Irregularly irregular ventricular rhythm

Question 8

What is Paroxysmal Atrial Fibrillation?

Answer 8

Episodes of atrial fibrillation that reoccur and spontaneously resolve back to sinus rhythm.

These episodes can last between 30 seconds and 48 hours.

Question 9

Principles of treatment

Answer 9

Rate or rhythm control
Anticoagulation to prevent strokes

Question 10

Rate control in all but:

Answer 10

A reversible cause for their AF
New onset atrial fibrillation (within the last 48 hours)
Heart failure caused by atrial fibrillation
Symptoms despite being effectively rate controlled

Question 11

Options for rate control

Answer 11

Beta blocker first-line (e.g., atenolol or bisoprolol)

Question 12

Aim of rhythm control

Answer 12

Return the patient to normal sinus rhythm

Question 13

What can rhythm control be done by?

Answer 13

Cardioversion
Long-term rhythm control using medications

Question 14

What are the options for cardioversion?

Answer 14

Immediate cardioversion
Delayed cardioversion

Question 15

When is immediate cardioversion used?

Answer 15

Present for less than 48 hours
Causing life-threatening haemodynamic instability

Question 16

What are the options for cardioversion?

Answer 16

Pharmacological cardioversion
Electrical cardioversion

Question 17

Pharmacological cardioversion

Answer 17

Flecainide
Amiodarone (the drug of choice in patients with structural heart disease)

Question 18

What happens with electrical cardioversion?

Answer 18

shock the heart back into sinus rhythm. It involves using a cardiac defibrillator machine to deliver controlled shocks. This is usually done with sedation or general anaesthesia.

Question 19

What happens in delayed cardioversion?

Answer 19

Used if the atrial fibrillation has been present for more than 48 hours and they are stable. Electrical cardioversion is recommended.

The patient should be anticoagulated for at least 3 weeks before delayed cardioversion.

Question 20

Long term AF control

Answer 20

Beta blockers first-line
Dronedarone second-line for maintaining normal rhythm where patients have had successful cardioversion
Amiodarone is useful in patients with heart failure or left ventricular dysfunction

Question 21

Why are DOAC better than warfarin?

Answer 21

No monitoring is required
No issues with time in therapeutic range (provided they have good adherence)
No major interaction problems
Equal or slightly better than warfarin at preventing strokes in atrial fibrillation
Equal or slightly lower risk of bleeding than warfarin

Question 22

Most common DOAC indications

Answer 22

Stroke prevention in patients with atrial fibrillation
Treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE)
Prophylaxis of venous thromboembolism (DVTs and PEs) after a hip or knee replacement

Question 23

CHA2DS2-VASc

Answer 23

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)

Question 24

CHA2DS2-VASc score results and actions

Answer 24

0 – no anticoagulation
1 – consider anticoagulation in men (women automatically score 1)
2 or more – offer anticoagulation