Questions about atrial fibrillation are commonly asked in MRCP, there are a few important points to take note in order for you to be able to answer all cardiology questions about AF.
ECG for AF
ECG with AF is above and below is an ECG with sinus rhythmRemember that AF is a supraventricular tachyarrhythmia characterized by an ECG with absent P waves.
Causes for AF
Ischaemic heart disease
Thyrotoxicosis
Chronic rheumatic heart disease especially mitral stenosis
Post surgery
Chronic lung disease
Alcohol intoxication
Atrial septal defect
Types of Atrial Fibrillation
Remember that patients can have permanent AF ( it is unlikely the rhythm be reverted to sinus rhythm, you can anticipate this if patient has AF longer than 1 year, ECHO shows dilated left atrium ( >5cm)and patient is older. Patient may also have paroxysmal AF where there is possibility that the rhythm can be reverted to sinus rhythm.
Cardioversion
Cardioversion of AF to sinus rhythm can be done either electrically or pharmacologically,
However, remember that for elective cardioversion ( electrical or pharmacological), anticoagulate patients with AF >48 hours with warfarin 3-4 weeks before and after cardioversion.
Electrical cardioversion can be performed with synchronized DC shock of 50 till 100 J
Drugs used for Pharmacological Cardioversion
These drugs include amiodarone, flecanide, ibutilide, dofetilide, propafenone and quinidine. ( Learn more about amiodarone and flecanide)
Acute Management of Fast AF
Remember the principles below,
a) Sustain haemodynamic stability
b) Control ventricular rhythm
c) Anticoagulation
d) Find the underlying cause
e) Long term cardioversion ( rhythm control) or rate control
If a patient is admitted for fast atrial fibrillation, first thing to assess is patient’s haemodynamic stability, if patient’s blood pressure is unstable , urgent DC shock is needed. However, if the patient is stable and has fast AF, try to control the ventricular rhythm. Two common drugs are used, beta-blocker or digoxin, digoxin is preferred if patient has heart failure.
After the patient is stable, try to find the underlying cause for the problem. If you think patient has permanent AF or paroxysmal AF and planned for cardioversion, discuss anticoagulation ( warfarin) with the patient. You may just want to have rate control if you think patient is unlikely to be reverted back to sinus rhythm!
MRCP Questions
1)The following are recognised causes of atrial fibrillation EXCEPT
A anxiety
B hyperthyroidism
C atrial septal defect
D alcohol abuse
E COAD
ANSWER: A
2)A patient presenting with atrial fibrillation who has reverted to sinus rhythm is more likely to remain in sinus rhythm in the following circumstances:
A age >75 years old
B been commenced on warfarin
C left atrium size > 6 cm on ECHO
D short history on AF
E a ventricular rate on presentation of 130 bpm
ANSWER: D
3)Causes of atrial fibrillation include:
A Aortic stenosis
B Maladie de Roger VSD
C anxiety
D recent MI
E complete heart block
ANSWER: D
4) A 70 year-old lady presents with sudden breathlessness and chest discomfort. On examination, she was observed to have an irregular heart beat with rate of 140 bpm, BP 122/74 and normal heart sounds. On auscultation of the chest, Fine basal crepitations are heard. An ECG confirms fast. She is anticoagulated with heparin and given diuretics. Her heart rate remains rapid. What is the most appropriate management of the lady's AF?
1 ) Cardioversion.
2 ) IV amiodarone.
3 ) IV betablocker.
4 ) IV digoxin.
5 ) Oral quinidine therapy.
ANSWER: 4
5)A 70-year-old woman has a history of dyspnoea and palpitations for six months. An ECG at that time showed atrial fibrillation. She was given digoxin, diuretics and aspirin. She now presents with two short-lived episodes of altered sensation in the left face, left arm and leg. There is poor coordination of the left hand. ECHO was normal as was a CT head scan.
What is the most appropriate next step in management?
1 ) anticoagulation
2 ) carotid endarterectomy
3 ) clopidogrel
4 ) corticosteroid treatment
5 ) no action
ANSWER: 1
6)A 48 year-old MAN with atrial fibrillation is admitted for DC cardioversion.He is reverted to sinus rhythm. Which one of the following drugs would be most likely to maintain sinus rhythm following this procedure?
1 ) amiodarone
2 ) digoxin
3 ) heparin
4 ) sotalol
5 ) verapamil
ANSWER: 1
7)A 50-year-old politician presented with a strange fluttering sensation in his chest, but no chest pain. The symptoms had lasted 24 hours. An ECG revealed atrial fibrillation with a ventricular rate of 130 beats per minute.
Which one of the following drugs is most likely to restore sinus rhythm?
1 ) Adenosine
2 ) Bisoprolol
3 ) Digoxin
4 ) Flecainide
5 ) Verapamil
ANSWER: 4
8)The risk of embolic stroke with atrial fibrillation is increased in: EXCEPT
A Left ventricular ejection fraction of 60%.
B Diabetes mellitus.
C Controlled hypertension.
D Age greater than 75 years.
E Rheumatic mitral valve disease.
ANSWER: A
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