Atrial Fibrillation

Question 1

What is atrial fibrillation?

Answer 1

Uncoordinated, rapid and irregular contraction of the atria as a result of disorganised electrical activity (which overrides the normal electrical activity of the SA node)

Question 2

What are the clinical features of AF?

Answer 2

• Many patients asymptomatic

- If symptomatic: palpitations, SOB, syncope

Question 3

What are the two differentials for an irregularly irregular pulse?

Answer 3

• AF

- Ventricular ectopic

Question 4

What are the features of AF on an ECG?

Answer 4

• Absent P waves
• Narrow QRS complexes
• Irregularly irregular ventricular rhythm

Question 5

What is the definition of valvular AF?

Answer 5

Patients with AF who also have moderate/severe mitral stenosis or a mechanical heart valve

Question 6

What are the most common causes of AF?

Answer 6

AF affects Mrs SMITH:

• Sepsis
• Mitral valve pathology, e.g. stenosis
• IHD
• Thyrotoxicosis
• Hypertension

Question 7

What are the two main principles of treating AF?

Answer 7

• Rate vs. rhythm control

- Anticoagulation to prevent stroke

Question 8

Rate vs. rhythm control in AF… How do you decide which one to use?

Answer 8

• Can use rhythm (or rate) control if presentation LESS than 48 hours
• Always use rate control if presentation MORE than 48 hours

Question 9

Which drugs can be used for RATE control in AF?

Answer 9

• Beta-blocker, e.g. atenolol (usually first line)
• CCB (rate limiting) e.g. diltiazem - not in HF!!
• Digoxin

Question 10

What is the aim of rhythm control in AF?

Answer 10

To return the patient to normal sinus rhythm

Question 11

What are the options for rhythm control in AF?

Answer 11

Cardioversion:

• EITHER pharmacological, e.g. flecainide, or amiodarone (if evidence of structural heart disease)
• OR electrical

Question 12

What is paroxysmal AF?

Answer 12

When the AF comes and goes in episodes, usually not lasting more than 48 hours

Question 13

How is paroxysmal AF managed?

Answer 13

• “Pill in the pocket” approach using flecainide

- Anticoagulation

Question 14

What kind of drug is warfarin?

Answer 14

Vitamin K antagonist

Question 15

What is the target INR range for AF?

Answer 15

2-3

Question 16

How is warfarin metabolised?

Answer 16

By the cytochrome P450 system in the liver

Question 17

Which foods is INR affected by?

Answer 17

• Foods containing vitamin K, e.g. leafy green vegetables

- Foods affecting the CYP450 system, e.g. cranberry juice (inhibitor) and alcohol (inhibitor/inducer)

Question 18

Give some examples of DOACs

Which is used in patients with renal failure?

Answer 18

• Rivaroxaban
• Edoxaban
• Dabigatran
• Apixaban

Apixaban is used in patients with renal failure

Question 19

What are the components of the CHADSVASc score?

How is this score interpreted?

Answer 19

C - Congestive HF (1 point)
H - HTN (1 point)
A - Age > 75 (2 points)
D - Diabetes mellitus (1 point)
S - Stroke/TIA history (2 points)
V - Vascular disease (1 point)
A - Age 65-74 (1 point)
Sc - Sexual characteristics (women score 1 point)

Score of 1 for men = consider anticoagulation
Score of 2 for women = consider anticoagulation

Question 20

What are the components of the HASBLED score?

Answer 20

H - Hypertension
A - Abnormal renal/liver function
S - Stroke
B - Bleeding
L - Labile INRs (on warfarin)
E - Elderly
D - Drugs or alcohol