Atrial Fibrillation

Question 1

Which of the following is not a common complication of atrial fibrillation?

A	Acute ischaemic stroke
B	Cardiac failure
C	Pulmonary embolism
D	Acute mesenteric ischaemia
E	Acute limb ischaemia

Answer 1

Pulmonary embolism may be a cause of, but not commonly a direct consequence of, atrial fibrillation.
Patients with atrial fibrillation are at risk of developing blood clots within the left atrial appendage. Stasis of blood promotes thrombus formation.

Embolisation to the brain may cause cerebral ischaemia. Embolisation to the limbs may cause acute limb ischaemia and to the bowel will cause acute mesenteric ischaemia. Patients with atrial fibrillation are also at risk of developing cardiac failure. There is a temporal relationship between atrial fibrillation and cardiac failure related to a number of shared risk factors and neurohormonal dysregulation that occurs in both conditions.

Question 2

A 79-year-old female presents to the acute medical unit with a one-year history of dizzy spells. She does not complain of palpitations or chest pain but does get increasingly breathless on minimal exertion. She has a past medical history of hypertension and her only medication is ramipril. On examination, she has an irregular pulse at 130 bpm. An ECG is performed, which reveals an irregularly irregular rhythm and an absence of P waves. Her CHA2DS2-VASc score is 3.

What is the most appropriate initial treatment option from the choices below?

A    Apixaban and bisoprolol
B	Elective DC cardioversion
C	Heparin and amiodarone
D	Dabigatran monotherapy
E	Flecainide monotherapy

Answer 2

In patients with persistent AF the recommended management is rate control drugs (e.g. beta-blockers, calcium channel blockers) and anti-coagulation according to risk stratification.

A

Question 3

Older anti-coagulants (e.g. warfarin) are widely used for the prevention of thromboembolism in AF. However, patients should ideally be converted to DOACs - WHY?

Answer 3

Older anti-coagulants (e.g. warfarin) are widely used for the prevention of thromboembolism in AF. However, patients should ideally be converted to DOACs (e.g. apixaban) as they are better tolerated and do not require any monitoring. In the presence of new-onset AF, a DOAC should be offered first-line if advocated by a high CHADS-VASc score. If DOACs are not tolerated or not suitable, a vitamin K antagonist can be given.

Question 4

In the presence of new-onset AF, a … should be offered first-line if advocated by a high CHADS-VASc score.

Answer 4

In the presence of new-onset AF, a DOAC should be offered first-line if advocated by a high CHADS-VASc score.

Question 5

The … score is a risk stratification tool used in atrial fibrillation to determine those at greatest risk of cerebrovascular events.

Answer 5

The CHA2DS2-VASc score is a risk stratification tool used in atrial fibrillation to determine those at greatest risk of cerebrovascular events.

Question 6

NICE NG196 recommends anticoagulation (DOAC) in all patients with a score ≥ … taking into account bleeding risk. Anticoagulation should be considered in men with a score of 1. In women with a score of 1 due to gender, NICE does not consider this an indication for treatment.

Answer 6

NICE NG196 recommends anticoagulation (DOAC) in all patients with a score ≥ 2 taking into account bleeding risk. Anticoagulation should be considered in men with a score of 1. In women with a score of 1 due to gender, NICE does not consider this an indication for treatment.

Question 7

A variety of non-cardiac causes may precipitate atrial fibrillation.

Answer 7

Respiratory: COPD, pneumonia, pulmonary emoblism
Endocrine: hyperthyroidism, diabetes mellitus
Acute infection
Electrolyte disturbances: hypokalaemia, hypomagnesaemia, hyponatraemia
Drugs: bronchodilators, thyroxine
Lifestyle factors: alcohol, excessive caffeine, obesity

Question 8

Traditionally, causes of AF are divided into cardiac and non-cardiac. It is most commonly associated with hypertension, coronary artery disease and myocardial infarction.
Cardiac causes?

Answer 8

Hypertension
Ischaemic heart disease
Valvular disease (e.g. rheumatic heart disease)
Myocardial infarction
Cardiomyopathy

Question 9

One of the major complications of AF is..

Answer 9

One of the major complications of AF is the formation of a thrombus (i.e. blood clot) within the atria.

Question 10

Symptoms AF

Answer 10

Asymptomatic
Palpitations
Shortness of breath
Angina
Presyncope
Lethargy

Question 11

AF signs

Answer 11

Irregularly irregular pulse
Absent ‘a’ wave on JVP: corresponds to atrial contraction
Tachycardia
Hypotension
Features of heart failure: bibasal crackles, raised JVP, peripheral oedem

Question 12

Causes of an irregularly irregular pulse include:

Answer 12

Atrial fibrillation
Premature beats (i.e. ectopics)
Atrial flutter with variable block
Other atrial tachyarrhythmias (e.g. multi-focal atrial tachycardia)

Question 13

If AF is suspected, a formal diagnosis is made by performing a 12-lead ECG. Alternatively, if paroxysmal AF is suspected then ambulatory ECG monitoring can be requested:

Answer 13

24-hour monitoring: for asymptomatic episodes or symptomatic episodes < 24 hours apart
48-hour monitoring (occasionally completed)
7-day monitoring: longer period of monitoring if symptomatic episodes are infrequent
Loop recorder: a small device placed surgically under the skin. Provides continuous monitoring up to 3 years.
New technology: new software is available on smartwatches and phones that monitor for AF

Question 14

Atrial fibrillation is characterised by …

Answer 14

Atrial fibrillation is characterised by an irregularly irregular rhythm, absent P waves and fibrillating baseline.

Question 15

Both transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE) and important in the work-up and management of AF:

Answer 15

TTE: basic echo that involves imaging of the heart via the chest wall with an ultrasound probe
TOE: invasive echo that involves the insertion of an endoscope into the oesophagus to look at the heart with an ultrasound internally

Question 16

TTE

Answer 16

A TTE is commonly requested routinely in patients with new-onset AF. This is because it helps with the long-term management of AF, particularly when a rhythm control strategy is opted for (discussed further below). It is also needed in patients where there is high risk of suspicion of an underlying structural heart defect (e.g. valvular heart disease or left ventricular dysfunction) or to refine risk stratification for the use of anticoagulation.

Question 17

TOE

Answer 17

A TOE is a more specialised imaging investigation that is typically used to better clarify structural abnormalities (e.g. valvular heart disease). It is also used to exclude a thrombus within the left atrial appendage (LAA) prior to cardioversion. This is because during cardioversion there is a risk of causing an embolic event and TOE is much better at visualising the LAA.

Question 18

Management of AF comprises a combination of …

Answer 18

Management of AF comprises a combination of rate control, rhythm control and prevention of thromboembolic events.

Question 19

NICE released new guidelines (NG196) for the diagnosis and management of AF in 2021 (NG196). This summarises the key components of management including:

Answer 19

Rate control
Rhythm control
Management of acute AF
Prevention of thromboembolic events

Question 20

In any new-onset AF, the underlying causes should be identified and treated (e.g. antibiotics for infection, antiplatelets for myocardial infarction). A decision then needs to be made as to whether patients should be treated with a rate or rhythm control strategy. Finally, patients need to be risk-stratified to decide on whether anticoagulation to reduce the risk of embolic events (e.g. stroke) is appropriate.

Answer 20

In any new-onset AF, the underlying causes should be identified and treated (e.g. antibiotics for infection, antiplatelets for myocardial infarction). A decision then needs to be made as to whether patients should be treated with a rate or rhythm control strategy. Finally, patients need to be risk-stratified to decide on whether anticoagulation to reduce the risk of embolic events (e.g. stroke) is appropriate.

Question 21

This is the most common type of management and aims to control AF that presents with a fast ventricular rate. In patients with AF that is not of acute onset, rate control is usually the first-line strategy.

Options include:

Answer 21

Beta-blockers (e.g. metoprolol, bisoprolol)
Rate-limiting calcium channel blockers (e.g. verapamil, diltiazem)
Digoxin: usually reserved for patients that do no or very little physical exercise (e.g. bedbound) or other drugs are inappropriate (contraindicated, side-effects, patient preference).

Question 22

Rhythm control aims to restore and/or maintain the heart in normal sinus rhythm. Rhythm control may either be pharmacological or electrical:

Answer 22

Pharmacological: using medications to restore and/or maintain sinus rhythm. Examples include amiodarone, flecainide, beta-blockers (e.g. sotalol).
Electrical: using DC cardioversion to revert the heart into sinus rhythm.

Question 23

Outside of acute onset AF, a rhythm control strategy is indicated in patients with ongoing symptomatic AF despite adequate rate control to improve quality of life. Patients who may be suitable for rhythm control include:

Answer 23

New-onset AF
Identifiable reversible cause
Heart failure (exacerbated by AF)
Associated with atrial flutter (and ablation strategy appropriate)
Rhythm control felt more suitable (clinical judgement)

Question 24

In patients presenting acutely with AF, it is first important to perform a clinical assessment (e.g. ABCDE) and determine haemodynamic stability:

Answer 24

Life-threatening haemodynamic instability: carry out emergency electrical cardioversion
Haemodynamic stability: rate or rhythm control strategies

Question 25

In patients who are stable, the key determinant to further management is the precise time of onset. This is because cardioversion (restoration of sinus rhythm) is associated with an increased risk of embolic events.

Answer 25

Onset > 48 hours or unclear: increased risk of thromboembolism. Patients need adequate anticoagulation (minimum 3 weeks) to reduce thromboembolic risk prior to cardioversion. Onset < 48 hours: low risk of thromboembolism. Patients' can be considered for immediate electrical or pharmacological cardioversion.

Question 26

In patients with early cardioversion (performed within 48 hours), pharmacological cardioversion is usually preferred with amiodarone or …. Assessment of the cardiac function with echocardiography is required because flecainide (type I antiarrhythmic) is dangerous in structural heart disease (pro-arrhythmic and increased risk of sudden cardiac death). Electrical cardioversion is usually preferred in delayed cardioversion.

Answer 26

In patients with early cardioversion (performed within 48 hours), pharmacological cardioversion is usually preferred with amiodarone or flecainide. Assessment of the cardiac function with echocardiography is required because flecainide (type I antiarrhythmic) is dangerous in structural heart disease (pro-arrhythmic and increased risk of sudden cardiac death). Electrical cardioversion is usually preferred in delayed cardioversion.

Question 27

Following cardioversion, anticoagulation is commonly given for a minimum of … weeks, even in patients at low-risk because of the risk of thromboembolism from atrial stunning post-restoration of sinus rhythm. Long-term continuation is then guided by usual risk stratification (i.e. CHADS-VASc).

Answer 27

Following cardioversion, anticoagulation is commonly given for a minimum of 4 weeks, even in patients at low-risk because of the risk of thromboembolism from atrial stunning post-restoration of sinus rhythm. Long-term continuation is then guided by usual risk stratification (i.e. CHADS-VASc).

Question 28

The two main options for anticoagulation include:

Answer 28

Vitamin K antagonists (e.g. warfarin): have been the mainstay for many years. Regular INR measurements are required. Target INR is usually 2-3. Direct-acting oral anticoagulants (DOACs): newer agents such as Direct Xa inhibitors (e.g. apixaban, rivaroxaban) and direct thrombin inhibitors (e.g. Dabigatran). No monitoring is required.

Question 29

The CHA2DS2-VASc score is a risk stratification tool to assess stroke risk in patients with AF.

Answer 29

All patients with new-onset AF should have a CHA2DS2-VASc score calculated, which is a risk stratification tool to determine the annual risk of developing an embolic event. The result of this score can be used to guide the need for anticoagulation. DOACs should be offered first-line with warfarin used if a DOAC is not suitable or not tolerated. NICE NG196 recommends anticoagulation (DOAC) in all patients with a score ≥ 2 taking into account bleeding risk. Anticoagulation should be considered in men with a score of 1. In women with a score of 1 due to gender, NICE do not consider this an indication for treatment. If a DOAC is not suitable or not tolerated, patients should be offered a vitamin K antagonist (e.g. warfarin).

Question 30

Patients with AF should undergo a formal risk assessment for major bleeding with anticoagulation using the ORBIT score.

Answer 30

In patients with AF who are being considered for anticoagulation based on the CHA2DS2-VASc score, an ORBIT score should be calculated. OBRIT is a risk stratification tool to identified patients at risk of major bleeding events on anticoagulation. There are five total demains with a score from 0-7: Haemoglobin (< 130 g/L males or < 120 g/L females): +2 Age > 74 years: +1 Bleeding history (GI bleeding, intracranial bleeding, haemorrhagic stroke): +2 eGFR < 60 mL/min/1.73 m2: +1 Treatment with antiplatelet: +1

Question 31

In patients with AF who are being considered for anticoagulation based on the CHA2DS2-VASc score, an ORBIT score should be calculated. OBRIT is a risk stratification tool to identified patients at risk of major bleeding events on anticoagulation. There are five total demains with a score from 0-7:

Answer 31

Haemoglobin (< 130 g/L males or < 120 g/L females): +2 Age > 74 years: +1 Bleeding history (GI bleeding, intracranial bleeding, haemorrhagic stroke): +2 eGFR < 60 mL/min/1.73 m2: +1 Treatment with antiplatelet: +1

Question 32

HAS-BLED is an old risk stratification tool that was commonly used for the assessment of bleeding risk. NICE now recommends ORBIT as it has a higher accuracy of predicting bleeding risk. However, due to the widespread use of HAS-BLED, it may still be used until ORBIT is more formally embedded in clinical pathways and electronic systems.

Answer 32

HAS-BLED is an old risk stratification tool that was commonly used for the assessment of bleeding risk. NICE now recommends ORBIT as it has a higher accuracy of predicting bleeding risk. However, due to the widespread use of HAS-BLED, it may still be used until ORBIT is more formally embedded in clinical pathways and electronic systems.

Question 33

Catheter ablation

Answer 33

AF catheter ablation is an alternative treatment to long-term anti-arrhythmic drugs to maintain sinus rhythm that involves modification of the left atrium through ablation.

Question 34

Patients with infrequent paroxysmal AF may be treated with a '…’ regimen

Answer 34

Patients with infrequent paroxysmal AF may be treated with a 'pill-in-pocket' regimen.

Question 35

Patients with infrequent episodes of paroxysmal AF may not require long-term antiarrhythmic therapy. In selected outpatients, self-administration of .. at the onset of AF to induce pharmacological cardioversion may be preferred to in-hospital pharmacological cardioversion. The drug should be safe to use, previously shown efficacy and there be no evidence of structural or ischaemic heart disease. … may be combined with a beta-blocker in this type of patient-led cardioversion.

Answer 35

Patients with infrequent episodes of paroxysmal AF may not require long-term antiarrhythmic therapy. In selected outpatients, self-administration of flecainide at the onset of AF to induce pharmacological cardioversion may be preferred to in-hospital pharmacological cardioversion. The drug should be safe to use, previously shown efficacy and there be no evidence of structural or ischaemic heart disease. Flecainide may be combined with a beta-blocker in this type of patient-led cardioversion.

Question 36

AF is associated with both cardiac and non-cardiac complications.

Answer 36

Cardiac ``` Heart failure Tachycardia-induced cardiomyopathy Ischaemia Sudden cardiac arrest Non-cardiac ``` Thromboembolic events: stroke, TIA, mesenteric ischaemia, ischaemic limb Collapse Bleeding events (anticoagulation)