Atrial fibrillation (AF) Flashcards
What is AF?
AF is a chaotic, irregular atrial rhythm at 300-600 bpm.
The AV node responds intermittently, hence an irregular ventricular rhythm.
What happens to the CO in AF?
CO drops by 10-20% as the ventricles aren’t primed reliably by the atria.
Causes of AF
HF Mitral valve disease Pneumonia Ischaemic heart disease Rare causes: Cardiomyopathy Constrictive pericarditis Sick sinus syndrome Lung cancer Endocarditis Haemochromatosis Sarcoid
What does the term ‘lone AF’ mean?
This means that no cause of AF can be found.
Signs and symptoms of AF
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
Why should you do a full systemic examination for a patient with AF?
AF is often associated with non-cardiac diseases.
Investigations with AF
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
Types of AF
Paroxysmal AF
Persistent AF
Permanent AF
ECG recording in paroxysmal AF
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.
When should you do an echocardiogram in the diagnosis of AF?
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.
Risk factors for AF
HTN CAD CHF Old age DM Rheumatic valvular disease Alcohol abuse Male sex Presence of other arrhythmias Smoking
Differentials of AF
Atrial flutter
Multifocal atrial tachycardia
Atrial tachycardia with variable AV conduction
Sinus rhythm with premature atrial contractions.
Management of AF
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.
When is emergency cardioversion indicated?
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)
What are the signs of life-threatening haemodynamic instability?
Shock
MI
Syncope
Heart failure
Treatment of acute AF with no life-threatening haemodynamic instability
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.
When should anticoagulation be offered in a patient with AF?
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.
What are the factors indicating a high risk of AF?
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.
What are the types of rhythm control?
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.
Management of AF using pharmacological cardioversion
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.
When to offer rate or rhythm control
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.
The treatment used in rate control for AF
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.
What are the drugs used for long-term rhythm control for AF?
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.
What is the ‘pill in the pocket’ strategy?
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.
When should consider ablation?
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.
When is dronedarone used?
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.
