Atrial fibrillation/flutter

Question 1

Define atrial fibrillation

Answer 1

Characterised by rapid, chaotic and ineffective atrial electrical conduction.

Often subdivided into:
Permanent
Persistent
Paroxysmal

Question 2

Explain the aetiology and risk factors of atrial fibrillation

Answer 2

There may be no identifiable cause

Secondary causes lead to an abnormal atrial electrical pathway that results in AF

Systemic Causes
Thyrotoxicosis
Hypertension
Pneumonia
Alcohol

Heart Causes
Mitral valve disease
Ischaemic heart disease
Rheumatic heart disease
Cardiomyopathy
Pericarditis
Sick sinus syndrome
Atrial myxoma

Lung Causes
Bronchial carcinoma
PE

Question 3

Summarise the epidemiology of atrial fibrillation

Answer 3

VERY COMMON in the elderly
Present in 5% of those > 65 years
May be paroxysmal

Question 4

Recognise the presenting symptoms of atrial fibrillation

Answer 4

Often ASYMPTOMATIC
Palpitations
Syncope (if low output)
Symptoms of the cause of AF

Question 5

Recognise the signs of atrial fibrillation on physical examination

Answer 5

Irregularly irregular pulse
Difference in apical beat and radial pulse
Check for signs of thyroid disease and valvular disease

Question 6

Identify appropriate investigations for atrial fibrillation

Answer 6

ECG - Uneven baseline with absent p waves
Irregular intervals between QRS complexes
Atrial flutter = saw-tooth

Bloods
Cardiac enzymes
TFT
Lipid profile
U&Es, Mg2+ and Ca2+
Because there is increased risk of digoxin toxicity with hypokalaemia, hypomagnesaemia and hypercalcaemia

Echocardiogram
May show:
Mitral valve disease
Left atrial dilatation
Left ventricular dysfunction
Structural abnormalities

Question 7

Generate a management plan for atrial fibrillation

Answer 7

First and foremost, try to treat any reversible causes
(e.g. thyrotoxicosis, chest infection)
There are TWO main components to AF management:

RHYTHM CONTROL
If > 48 hrs since onset of AF
Anticoagulate for 3-4 weeks before attempting cardioversion

If < 48 hrs since onset of AF
DC cardioversion (2 x 100 J, 1 x 200 J)
Chemical cardioversion: flecainide or amiodarone

NOTE: flecainide is contraindicated if there is a history of ischaemic heart disease

RATE CONTROL - Chronic (Permanent) AF
Control ventricular rate with:
Digoxin
Verapamil
Beta-blockers
Aim for ventricular rate ~ 90 bpm

Question 8

Prophylaxis against AF

Answer 8

Sotalol
Amiodarone
Flecainide

Consider pill-in-the-pocket (single dose of a cardioverting drug (e.g. flecainide) for patients with paroxysmal AF) strategy for suitable patient

Question 9

AF STROKE RISK STRATIFICATION

Answer 9

LOW RISK patients can be managed with aspirin
HIGH RISK patients require anticoagulation with warfarin

This is based on the CHADS-Vasc Score

Risk factors include:
Previous thromboembolic event
Age > 75 yrs
Hypertension
Diabetes
Vascular disease
Valvular disease
Heart failure
Impaired left ventricular function

Question 10

Identify the possible complications of atrial fibrillation

Answer 10

THROMBOEMBOLISM - Embolic stroke risk of 4% per year: Risk is increased with left atrial enlargement or left ventricular dysfunction

Worsening of existing heart failure

Question 11

Summarise the prognosis for patients with atrial fibrillation

Answer 11

Chronic AF in a disease heart does not usually return to sinus rhythm