Cardiology - Atrial Fibrillation Flashcards

1
Q

Why can AF increase the risk of thrombus formation?

A

Uncoordinated atrial activity causing blood to stagnate in the atria

5x higher risk in AF for a stroke

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2
Q

What lifestyle factors can cause AF?

A

Alcohol
Caffeine

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3
Q

What are the most common causes of AF?

A

SMITH

Sepsis
Mitral valve pathology
Ischaemic heart disease
Thyrotoxicosis
Hypertension

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4
Q

What is the key examination finding in AF?

A

Irregularly irregular pulse

May also be ventricular ectopics

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5
Q

What happens to ventricular ectopics during exercise?

A

Ventricular ectopics disappear when heart rate is high enough and heart rate becomes normal

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6
Q

What are the ECG findings for AF?

A

Absent P waves
Narrow QRS complex tachycardia
Irregularly irregular

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7
Q

What is paroxysmal atrial fibrillation?

A

Episodes of AF that reoccur and spontaneously resolve back to sinus rhythm

Episodes last between 30 seconds and 48 hours

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8
Q

What investigations are used for suspected paroxysmal AF?

A

24 hour ambulatory ECG (Holter monitor)
Cardiac event recorder (lasts 1-2 weeks)

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9
Q

What is valvular atrial fibrillation?

A

AF with significant mitral stenosis or a mechanical heart valve

Assumption is that AF has been caused by valvular issue

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10
Q

How is AF managed?

A

Rate or rhythm control
Anticoagulation to prevent strokes

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11
Q

How do ventricles fill in AF?

A

Suction and gravity as atrial contractions are not coordinated

So higher heart rate less time for filling, reducing CO

Rate control to bring heart rate down to increase filling

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12
Q

When should patients with AF not be given a rate control as first line?

A

A reversible cause for AF

New onset within 48 hours

Heart failure caused by AF

Symptoms despite being controlled well

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13
Q

What options are used for rate control in AF?

A

Beta blocker (atenolol or bisoprolol)
Calcium-channel blocker (diltiazem or verapamil)
Digoxin

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14
Q

When is rhythm controlled offered to AF patients?

A

Reversible cause
New onset within 48 hours
Heart failure due to AF
Symptoms despite being controlled well

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15
Q

What options are used for rhythm control?

A

Cardioversion
Long-term rhythm control with medications

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16
Q

When is immediate vs delayed cardioversion used?

A

Immediate
- Present for less than 48 hours
- Causes life-threatening haemodynamic instability

Delayed
- AF present for more than 48 hours and stable
- Patient should be anticoagulated for at least 3 weeks
- If patient has developed a clot in the atria reverting to sinus can mobilise the clot

17
Q

What is used for immediate cardioversion?

A

Flecainide
Amiodarone (drug of choice with structural heart disease)
Electrical cardioversion

18
Q

What is used for long-term rhythm control whilst waiting for cardioversion?

A

Beta blockers- first line

Dronedarone- second line, maintaining normal rhythm where patients have had successful cardioversion

Amiodarone- HF or LV dysfunction

19
Q

How is paroxysmal AF managed?

A

Flecainide is used when the patient feels symptoms are starting

Risk of flecainide converting AF into flutter with 1:1 AV conduction causing a very fast ventricular rate

20
Q

What is ablation used for?

A

Where drug treatment for rate or rhythm is not adequate or tolerated

Left atrial ablation (remove abnormal electrical pathways)

or

AVN ablation and permanent pacemaker

Anticoagulation is still needed

21
Q

What anticoagulants are used for AF?

A

First line
DOACs e.g. rivaroxaban

Second line
Warfarin- if DOACs are contraindicated

22
Q

What is the mechanism of action of Dabigatran?

A

Direct thrombin inhibitor

23
Q

How often are DOACs taken?

A

Apixaban and dabigatran
Twice daily

Edoxaban and rivaroxaban
Once daily

24
Q

What agents can be used to reverse effects in uncontrolled life-threatening bleeding due to DOACs?

A

Andexanet alfa (apixaban and rivaroxaban)

Idarucizumab (dabigatran)

25
Q

What are the advantages of DOACs vs Warfarin?

A

No monitoring needed
No issues with time in therapeutic range
No major interaction problems
Better at preventing strokes in AF
Lower bleeding risk

26
Q

What is the INR (international normalised ration)?

A

Prothrombin time of an average healthy adult

INR of 1 is normal

INR target for AF is 2-3

27
Q

What is TTR (time in therapeutic range)?

A

Percentage of time that INR is in target range

If the INR is too low patient is at risk of stroke

Too high patient is at risk of bleeding

28
Q

What can be used to reverse effects of warfarin?

A

Vitamin K

29
Q

What is CHA2DS2VASc for?

A

Tool used to assess if a patient with AF should start anticoagulation

C– Congestive heart failure
H – Hypertension
A2 – Age above 75
D – Diabetes
S2 – Stroke or TIA previously
V – Vascular disease
A – Age 65 – 74
S – Sex (female)

0- No anticoagulation
1- Consider in men (women automatically score 1)
2 - Offer anticoagulation

30
Q

What is an ORBIT score used for?

A

Assessing risk of major bleeding in patients with AF taking anticoagulation

Over 75
Renal impairment (GFR < 60)
Bleeding previously (GI or intracranial bleeding
Iron (low Hb or haematocrit)
Taking antiplatelet medication

31
Q

What is left atrial appendage occlusion?

A

Left atrial appendage is a small pouch where thrombi commonly form

Occlusion is where the septum is punctured to access the LA and a plug is placed to prevent blood entering that area