Atrial Fibrillation

Question 1

What is atrial fibrillation (AF)?

Answer 1

Supraventricular tachyarrhythmia characterized by disorganized and rapid atrial activation and uncoordinated atrial contraction

AF occurs at a rate of over 100 bpm.

Question 2

What mnemonic is used to remember the causes of atrial fibrillation?

Answer 2

PIRATES

Each letter represents a different cause.

Question 3

What does the ‘P’ in the PIRATES mnemonic stand for?

Answer 3

Pulmonary (PE, COPD), post-operative

PE refers to pulmonary embolism and COPD refers to chronic obstructive pulmonary disease.

Question 4

What does the ‘I’ in the PIRATES mnemonic stand for?

Answer 4

Ischaemic heart disease (MI, CAD), IV central line

MI refers to myocardial infarction and CAD refers to coronary artery disease.

Question 5

What does the ‘R’ in the PIRATES mnemonic stand for?

Answer 5

Rheumatic heart disease (mitral valve diseases)

Rheumatic heart disease can occur after rheumatic fever.

Question 6

What does the ‘A’ in the PIRATES mnemonic stand for?

Answer 6

Anaemia, alcohol, age (over 65 yrs old)

These factors can increase the risk of developing AF.

Question 7

What does the ‘T’ in the PIRATES mnemonic stand for?

Answer 7

Thyroid overactivity

Hyperthyroidism can lead to increased heart rate and AF.

Question 8

What does the ‘E’ in the PIRATES mnemonic stand for?

Answer 8

Endocarditis

Endocarditis is an infection of the inner lining of the heart.

Question 9

What does the ‘S’ in the PIRATES mnemonic stand for?

Answer 9

Sepsis, sick sinus syndrome, sleep apnea

These conditions can also contribute to the development of AF.

Question 10

Is atrial fibrillation more common in men or women?

Answer 10

Much more common in men

Studies indicate a significant gender disparity in the prevalence of AF.

Question 11

What are the two mechanisms of atrial fibrillation pathophysiology?

Answer 11

1. Atrial ectopic focal discharges
2. Reentry circuit

These mechanisms explain how AF develops in the heart.

Question 12

What are atrial ectopic focal discharges?

Answer 12

Excitable group of cells that causes a premature heart beat outside the normally functioning SA node

Ectopic foci are typically located in the pulmonary veins.

Question 13

Where can ectopic foci be located besides the pulmonary veins?

Answer 13

Superior vena cava, coronary sinus, posterior left atrium, crista terminalis

These locations can also initiate abnormal heartbeats.

Question 14

What effect do ectopic foci have on the AV node?

Answer 14

Ectopic foci fire rapid depolarisations to AV node, causing irregular impulses

This results in a rapid irregular ventricular rate.

Question 15

What is a reentry circuit in atrial fibrillation?

Answer 15

Circuit in atrial myocardium that forms due to changes in atrial morphology

Changes can arise from ischaemic heart disease, age, and hypertension.

Question 16

What are the characteristics of slow-conducting areas in the atrial myocardium?

Answer 16

They have shorter refractory periods and need less time to rest before reactivation

This property contributes to the reentry mechanism.

Question 17

What are the two bifurcated conducting pathways in cardiac tissue?

Answer 17

Fast-conducting and slow-conducting pathways

These pathways are separated due to a fixed or functional unexcitable centre.

Question 18

What happens when an impulse collides with the slowly conducting antegrade impulse?

Answer 18

It extinguishes the impulse

This collision is a key feature of the reentry circuit.

Question 19

What occurs when a sufficiently premature stimulus enters the proximal common pathway?

Answer 19

It travels slowly down the slow pathway

This happens when the fast pathway is unexcitable due to its long refractory period.

Question 20

What may happen due to the slow conduction velocity in the slow pathway?

Answer 20

The fast pathway may no longer be refractory, allowing impulses to travel retrograde up the fast pathway

This can potentially activate the circuit repeatedly.

Question 21

What is atrial remodelling?

Answer 21

Structural and electrical changes in atria in response to atrial fibrillation

Changes occur within a few hours of AF onset and maintain fibrillation.

Question 22

What are the three main electrophysiological changes in the atria during atrial fibrillation?

Answer 22

• Cellular calcium ion loading
• Shortened refractory periods
• Increased ectopic activity

These changes contribute to the persistence of AF.

Question 23

What occurs during structural remodelling in atrial fibrillation?

Answer 23

Irreversible atrial fibrosis that predisposes to chronicity of AF

Structural changes can lead to long-term complications.

Question 24

What is contractile remodelling in the context of atrial fibrillation?

Answer 24

Impaired atrial dilation due to reduced contractibility and increased compliance

This affects the heart’s ability to pump effectively.

Question 25

List some common presentations of atrial fibrillation.

Answer 25

* Fatigue and lack of energy * Sleeping disturbances * Shortness of breath (SOB) on exertion * Irregular pulse with palpitations * Dizziness or light-headedness * Chest pain/angina * Syncope * Thromboembolic events (e.g., stroke) * Psychological effects (e.g., anxiety) ## Footnote Symptoms can vary widely among patients.

Question 26

What is first-diagnosed AF?

Answer 26

AF that has not been diagnosed before ## Footnote This is the initial identification of atrial fibrillation in a patient.

Question 27

Define paroxysmal AF.

Answer 27

More than one episode of AF that self-terminates spontaneously within 7 days ## Footnote Most cases of paroxysmal AF terminate within 48 hours.

Question 28

What characterizes persistent AF?

Answer 28

Continuous AF that lasts more than 7 days ## Footnote This type of AF requires different management strategies.

Question 29

What is long-standing persistent AF?

Answer 29

Continuous AF that lasts 1 year or longer ## Footnote It is when a rhythm control strategy is considered.

Question 30

What is permanent AF?

Answer 30

AF with a joint decision of patient and doctor to have no further attempts to restore or maintain sinus rhythm ## Footnote It represents a stage where treatment goals change significantly.

Question 31

True or False: Atrial fibrillation can lead to thromboembolic events.

Answer 31

True ## Footnote Examples include stroke and heart failure.

Question 32

Fill in the blank: Atrial remodelling involves structural and _______ changes in response to atrial fibrillation.

Answer 32

electrical

Question 33

What is the primary investigation for atrial fibrillation?

Answer 33

12-lead ECG ## Footnote No P wave indicates the SA node is not functioning, and fibrillatory F waves are present.

Question 34

What are the characteristics of the QRS complexes in atrial fibrillation?

Answer 34

Narrow QRS complexes with irregular rhythm.

Question 35

What additional investigations are needed for atrial fibrillation?

Answer 35

Blood pressure, blood tests (FBC, LFTs, thyroid function tests, U&Es, coagulation screen), echocardiogram (TTE preferred over TOE), Holter monitor.

Question 36

What is the first-line approach for managing atrial fibrillation?

Answer 36

Rate control is tried before rhythm control.

Question 37

What are the initial monotherapy options for rate control?

Answer 37

Beta-blocker or calcium channel blocker.

Question 38

What is the alternative for patients with non-paroxysmal AF who do little/no exercise?

Answer 38

Digoxin monotherapy.

Question 39

What is the management approach if monotherapy is ineffective?

Answer 39

Combination therapy with 2 of either beta-blocker, diltiazem, or digoxin.

Question 40

When is rhythm control considered in atrial fibrillation management?

Answer 40

If rate control is ineffective.

Question 41

What is the thromboembolic risk if sinus rhythm is restored within 48 hours of acute AF?

Answer 41

The thromboembolic risk is low, and anticoagulation is not required.

Question 42

What is the emergency procedure for a patient with haemodynamic instability?

Answer 42

Emergency electrical cardioversion.

Question 43

What are the options for a patient without haemodynamic instability?

Answer 43

Electrical cardioversion or pharmacological cardioversion.

Question 44

What is pharmacological cardioversion?

Answer 44

Using IV or oral antiarrhythmic drugs to convert abnormal rhythm into normal sinus rhythm.

Question 45

What antiarrhythmic drugs are used if there is no structural/ischaemic heart disease?

Answer 45

Oral flecainide or propafenone.

Question 46

What antiarrhythmic drug is used if there is aortic stenosis?

Answer 46

IV amiodarone.

Question 47

What antiarrhythmic drugs are used if there is CAD, left ventricular failure, or heart failure?

Answer 47

IV amiodarone or vernakalant.

Question 48

What is chronic rhythm control?

Answer 48

Long-term antiarrhythmic therapy to improve symptoms.

Question 49

What are the options for chronic rhythm control?

Answer 49

Patient can either choose pharmacological cardioversion or catheter ablation.

Question 50

What is pharmacological cardioversion?

Answer 50

A method used to restore normal heart rhythm.

Question 51

When is pharmacological cardioversion used?

Answer 51

If there is no structural/ischaemic heart disease.

Question 52

Which drugs are used for pharmacological cardioversion without structural heart disease?

Answer 52

Flecainide, propafenone, dronedarone, or sotalol.

Question 53

What is a risk associated with Class I drugs like flecainide and propafenone?

Answer 53

High risk of ventricular proarrhythmia and potential for sudden death in heart failure, LV dysfunction, and coronary artery disease.

Question 54

What drugs are used for pharmacological cardioversion if there is CAD/valve disease/severe LVH?

Answer 54

Amiodarone, dronedarone, sotalol.

Question 55

What drug is used for pharmacological cardioversion in heart failure?

Answer 55

Amiodarone.

Question 56

What is catheter ablation?

Answer 56

A minimally invasive procedure that creates scars to terminate/modify electrical impulses causing irregular heart rhythm.

Question 57

How is catheter ablation performed?

Answer 57

Using electrode catheters through heart blood vessels.

Question 58

What is radiofrequency ablation (RFA)?

Answer 58

A method that causes tissue damage using heat.

Question 59

What is Arctic Front Cryoablation?

Answer 59

A method that causes tissue damage by freezing the target region.

Question 60

What is a pacemaker?

Answer 60

A device used to regulate heart rhythm.