Atrial Fibrillation

Question 1

What is Atrial Fibrillation?

Answer 1

Atrial Fibrillation is a condition in which the atria fail to contract efficient, and depolarise spontaneously in a rapid, uncoordinated fashion. This results in some of these impulses being sent to the AVN and as such an irregularly irregular ventricular pulse occurs. The impaired contraction of the atria can cause stagnation of blood, leading to thrombus formation and a risk of embolism, which could go on to cause stroke. It can also cause a reduction in cardiac output which may lead to heart failure.

There are 3 main types of atrial fibrillation:
Paroxysmal AF - attacks start and stop without intervention
Persistent AF - Attacks do not stop spontaneously and require medical help to stop them
Permanent AF - AF where medical treatment cannot maintain sinus rhythm

Question 2

What are the causes of Atrial Fibrillation?

Answer 2

Common - Ischaemic heart disease, Hypertension, Valvular heart disease, Hyperthyroidism, Infection, Caffeine, Alcohol

Others - Pericarditis and cardiomyopathy, Heart failure, Alcohol, Pulmonary embolism, pneumonia, COPD, Cor pulmonale, Idiopathic

Question 3

What will you find on a history taking of Atrial Fibrillation?

Answer 3

Symptoms:
Fast irregular palpitations - Sudden onset, defined duration, sudden offset
Breathlessness - More common in patients with underlying hearty disease
General Malaise, tiredness
Chest Pain
Stroke
Asymptomatic

Specific Questions to ask:
Black outs - very uncommon in AF
Ask about the type of palpitations - Non-cardiac palpitations come on gradually and not suddenly

Differentials:
Another type of Arrhythmia
Anxiety

Question 4

What will you find on examination of Atrial Fibrillation?

Answer 4

End of the bed:
Fever – Infection can be a cause 
Hands:
Fast or Slow heart rate
Irregularly irregular pulse
Hypertension – Can be a cause 
Radial-Apical Pulse deficit (Not every apical beat can be felt at radial pulse)
Neck:
Goitre – Hyperthyroidism can be a cause
Face:
Thyroid eye disease - Hyperthyroidism can be a cause
Chest:
Heart Failure – Can be caused by AF 
Legs:
Oedema – Due to heart failure

Question 5

What investigations will you order in Atrial Fibrillation?

Answer 5

Bedside:
ECG - Irregularly Irregular, no P waves
24-hour ambulatory ECG monitor - If paroxysmal and frequent enough to be picked up in 24 hours
Event recorder ECG - If paroxysmal and not frequent enough for 24-hour monitoring

Bloods:
TFTs - Rule out hyperthyroidism
FBC - Anaemia may precipitate heart failure
U&E - Abnormal Potassium levels can potentiate arrhythmias and patient may be given digoxin
LFTs and coagulation screen – Given pre-warfarin

Imaging:
CXR – Looking for heart failure

Special Tests:
Transthoracic echocardiography - Looking for valve disease, heart failure or looking for clots pre cardioversion

Question 6

What is the treatment of Atrial Fibrillation?

Answer 6

Resuscitation:
A-E approach
Get IV Access/Give O2 to maintain sats of 94+ /Attach 12 lead ECG
Assessment with AMPLE history and brief examination
Get help - Cardiovascular registrar on call/Consider calling 2222
Frequent Observations - Constant or 15 minutely
If pulseless begin the arrest protocol
If unstable DC cardioversion

Medical:
Treat any underlying electrolyte abnormalities or conditions e.g. sepsis
Treat associated heart failure.
<48 hours since onset - Dc cardioversion or flecainide (Or amiodarone if flecainide contraindicated – Structural hearty disease or IHD), start Heparin (in case the cardioversion gets delayed)
>48 hours - Rate control with Beta/Calcium channel blockers (Digoxin or Amiodarone can be added if not controlled). Assess Chad2Vasc (assess clot risk) and HASBLED (assess bleeding risk) scores and give anti-coagulation if indicated (NOAC/Warfarin (target INR 2-3).
Refer for rhythm control (DC cardioversion or flecainide) 3 weeks after anticoagulation is started (Only if indicated). Pre-cardioversion they will require an echo to look for any thrombus
Flecainide can be used during attacks of paroxysmal AF
If not controlled by medical therapy then consider pacemaker therapy or atrial ablation

Lifestyle:
Avoid precipitating factors (e.g. Alcohol or caffeine)

Indications for rhythm control (Cardioversion) in stable patients:
Young patients
New onset AF
Heart Failure
AF caused by a treated precipitant