Atrial fibrillation (AF)

Question 1

What is AF?

Answer 1

AF is a chaotic, irregular atrial rhythm at 300-600 bpm.

The AV node responds intermittently, hence an irregular ventricular rhythm.

Question 2

What happens to the CO in AF?

Answer 2

CO drops by 10-20% as the ventricles aren’t primed reliably by the atria.

Question 3

Causes of AF

Answer 3

HF 
Mitral valve disease 
Pneumonia 
Ischaemic heart disease 
Rare causes: 
Cardiomyopathy
Constrictive pericarditis 
Sick sinus syndrome 
Lung cancer 
Endocarditis 
Haemochromatosis 
Sarcoid

Question 4

What does the term ‘lone AF’ mean?

Answer 4

This means that no cause of AF can be found.

Question 5

Signs and symptoms of AF

Answer 5

AF may be asymptomatic. 
Chest pain 
Palpitations 
Dyspnoea
Syncope 
Fatigue 
Dizziness 
Irregularly irregular pulse 
Apical pulse rate > radial rate 
1st heart sound is of variable intensity 
Signs of LVF

Question 6

Why should you do a full systemic examination for a patient with AF?

Answer 6

AF is often associated with non-cardiac diseases.

Question 7

Investigations with AF

Answer 7

ECG shows absent P waves and irregular QRS complexes.
Blood tests: U&Es, cardiac enzymes, thyroid function tests
Echocardiogram to look for left atrial enlargement-important to exclude cardiac pathologies (valvular disease and cardiomyopathies)
Mitral valve disease
Poor LV function and other structural abnormalities

Question 8

Types of AF

Answer 8

Paroxysmal AF
Persistent AF
Permanent AF

Question 9

ECG recording in paroxysmal AF

Answer 9

In people with suspected paroxysmal atrial fibrillation undetected by standard ECG recording:

• use a 24-hour ambulatory ECG monitor in those with suspected asymptomatic episodes or symptomatic episodes less than 24 hours apart
• use an event recorder ECG in those with symptomatic episodes more than 24 hours apart.

Question 10

When should you do an echocardiogram in the diagnosis of AF?

Answer 10

Perform transthoracic echocardiography in people with atrial fibrillation:

• for whom a baseline echocardiogram is important for long-term management
• for whom a rhythm-control strategy that includes cardioversion (electrical or pharmacological) is being considered
• in whom there is a high risk or a suspicion of underlying structural/functional heart disease (such as heart failure or heart murmur) that influences their subsequent management (for example, choice of an antiarrhythmic drug)
• in whom refinement of clinical risk stratification for antithrombotic therapy is needed.

Question 11

Risk factors for AF

Answer 11

HTN 
CAD 
CHF 
Old age 
DM 
Rheumatic valvular disease 
Alcohol abuse 
Male sex 
Presence of other arrhythmias 
Smoking

Question 12

Differentials of AF

Answer 12

Atrial flutter
Multifocal atrial tachycardia
Atrial tachycardia with variable AV conduction
Sinus rhythm with premature atrial contractions.

Question 13

Management of AF

Answer 13

Offer people with atrial fibrillation a personalised package of care.
Ensure that the package of care is documented and delivered and that it includes:
-stroke awareness and measures to prevent stroke
-rate control
-assessment of symptoms for rhythm control
-who to contact for advice if needed
-psychological support if needed
Assess the need for drug treatment for long-term rhythm control, taking into account the person’s preferences, associated comorbidities, risks of treatment and likelihood of recurrence of atrial fibrillation.

Question 14

When is emergency cardioversion indicated?

Answer 14

Carry out emergency electrical cardioversion, without delaying to achieve anticoagulation, in people with life-threatening haemodynamic instability caused by new-onset atrial fibrillation.
ABCDE then cardioversion (synchronized shock, start 150J)

Question 15

What are the signs of life-threatening haemodynamic instability?

Answer 15

Shock
MI
Syncope
Heart failure

Question 16

Treatment of acute AF with no life-threatening haemodynamic instability

Answer 16

In people with atrial fibrillation presenting acutely without life-threatening haemodynamic instability, offer rate or rhythm control if the onset of the arrhythmia is less than 48 hours, and start rate control if it is more than 48 hours or is uncertain.

Question 17

When should anticoagulation be offered in a patient with AF?

Answer 17

In people with new-onset AF who are receiving no, or subtherapeutic, anticoagulation therapy:
-in the absence of CI, offer heparin at initial presentation
-continue heparin until a full assessment has been made and appropriate antithrombotic therapy has been started, based on risk stratification
In people with a confirmed diagnosis of atrial fibrillation of recent onset (less than 48 hours since onset), offer oral anticoagulation if:
-stable sinus rhythm is not successfully restored within the same 48-hour period following the onset of acute AF
-there are factors indicating a high risk of AF recurrence
-it is recommended in preventing stroke.

Question 18

What are the factors indicating a high risk of AF?

Answer 18

A history of failed attempts at cardioversion
Structural heart disease (mitral valve disease
Left ventricular dysfunction or an enlarged left atrium)
A prolonged history of AF (more than 12 months)
Previous recurrences of AF.

Question 19

What are the types of rhythm control?

Answer 19

Pharmacological or electrical cardioversion
In people with atrial fibrillation in whom the duration of the arrhythmia is greater than 48 hours or uncertain and considered for long-term rhythm control, delay cardioversion until they have been maintained on therapeutic anticoagulation for a minimum of 3 weeks. During this period offer rate control as appropriate.

Question 20

Management of AF using pharmacological cardioversion

Answer 20

If pharmacological cardioversion has been agreed on clinical and resource grounds for new‑onset atrial fibrillation, offer:
A choice of flecainide or amiodarone to people with no evidence of structural or ischaemic heart disease
Amiodarone to people with evidence of structural heart disease.
Do not offer magnesium or a calcium-channel blocker for pharmacological cardioversion.

Question 21

When to offer rate or rhythm control

Answer 21

Offer rate control as the first-line strategy to people with atrial fibrillation, except in people:

• whose AF has a reversible cause
• who have heart failure thought to be primarily caused by AF
• with new-onset AF
• with atrial flutter whose condition is considered suitable for an ablation strategy to restore sinus rhythm
• for whom a rhythm control strategy would be more suitable based on clinical judgement.

Question 22

The treatment used in rate control for AF

Answer 22

Offer either a standard beta-blocker (that is, a beta-blocker other than sotalol) or a rate-limiting calcium-channel blocker as initial monotherapy to people with atrial fibrillation who need drug treatment as part of a rate control strategy.
Base the choice of the drug on the person’s symptoms, heart rate, comorbidities and preferences when considering drug treatment.

Consider digoxin monotherapy for people with non-paroxysmal AF only if they are sedentary (do no or very little physical exercise).

If monotherapy does not control symptoms, and if continuing symptoms are thought to be due to poor ventricular rate control, consider combination therapy with any 2 of the following:
a beta-blocker
diltiazem
digoxin.

Do not offer amiodarone for long-term rate control.

Consider pharmacological and/or electrical rhythm control for people with atrial fibrillation whose symptoms continue after heart rate has been controlled or for whom a rate-control strategy has not been successful.

Question 23

What are the drugs used for long-term rhythm control for AF?

Answer 23

If drug treatment for long-term rhythm control is needed, consider a standard beta-blocker (that is, a beta-blocker other than sotalol) as first-line treatment unless there are contraindications.
If beta-blockers are contraindicated or unsuccessful, assess the suitability of alternative drugs for rhythm control, taking comorbidities into account.
Consider amiodarone for people with a left ventricular impairment or heart failure.
Do not offer class 1c antiarrhythmic drugs such as flecainide or propafenone to people with known ischaemic or structural heart disease.

Question 24

What is the ‘pill in the pocket’ strategy?

Answer 24

Pill in the pocket
Where people have infrequent paroxysms and few symptoms, or where symptoms are induced by known precipitants (such as alcohol, caffeine), a ‘no drug treatment’ strategy or a ‘pill-in-the-pocket’ strategy should be considered and discussed with the person.
In people with paroxysmal AF, a ‘pill-in-the-pocket’ strategy should be considered for those who:
have no history of left ventricular dysfunction or valvular or ischaemic heart disease and
have a history of infrequent symptomatic episodes of paroxysmal AF and
have systolic BP greater than 100 mmHg and a resting HR above 70 bpm and are able to understand how to, and when to, take the medication.

Question 25

When should consider ablation?

Answer 25

If drug treatment has failed to control symptoms of atrial fibrillation or is unsuitable:
offer left atrial catheter ablation to people with paroxysmal atrial fibrillation
consider left atrial catheter or surgical ablation for people with persistent atrial fibrillation
discuss the risks and benefits with the person.
Consider left atrial surgical ablation at the same time as other cardiothoracic surgery for people with symptomatic atrial fibrillation.
Pace and ablate strategy
Consider pacing and atrioventricular node ablation for people with permanent atrial fibrillation and symptoms or left ventricular dysfunction thought to be caused by high ventricular rates.
When considering pacing and atrioventricular node ablation, reassess symptoms and the consequent need for ablation after pacing has been carried out and drug treatment further optimised.
Consider left atrial catheter ablation before pacing and atrioventricular node ablation for people with paroxysmal atrial fibrillation or heart failure caused by non-permanent (paroxysmal or persistent) atrial fibrillation.

Question 26

When is dronedarone used?

Answer 26

Dronedarone is recommended as an option for the maintenance of sinus rhythm after successful cardioversion in people with paroxysmal or persistent AF:
whose AF is not controlled by first-line therapy (usually including beta-blockers), that is, as a second-line treatment option and after alternative options have been considered and
who have at least 1 of the following cardiovascular risk factors:
hypertension requiring drugs of at least 2 different classes
diabetes mellitus
previous transient ischaemic attack, stroke or systemic embolism
left atrial diameter of 50 mm or greater or
age 70 years or older and
who do not have left ventricular systolic dysfunction and
who do not have a history of, or current, heart failure.
People who do not meet the criteria above who are currently receiving dronedarone should have the option to continue treatment until they and their clinicians consider it appropriate to stop.