Atrial Fibrillation Flashcards
Define Atrial Fibrillation?
Characterised by rapid, chaotic and ineffective atrial electrical conduction
How is Atrial Fibrillation often subdivided?
Permanent
Persistent
Paroxysmal
What is the aetiology of Atrial Fibrillation?
There may be no identifiable cause
Secondary Causes lead to an abnormal atrial electrical pathway that results in AF
What are the systemic causes of Atrial Fibrillation?
Thyrotoxicosis
Hypertension
Pneumonia
Alcohol
What are the cardiac causes of Atrial Fibrillation?
Mitral valve disease Ischaemic Heart Disease Rheumatic Heart Disease Cardiomyography Pericarditis Sick sinus syndrome Atrial myxoma
What are the lung causes of Atrial Fibrillation?
Bronchial Carcinoma
PE
What is the epidemiology of Atrial Fibrillation?
Very common in the elderly
Present in 5% of those >65 years
May be paroxysmal
What are the presenting symptoms of Atrial Fibrillation?
Often Asymptomatic
Palpitations
Syncope (if low output)
Symptoms of the cause of AF
What are the signs of Atrial Fibrillation on physical examination?
Irregularly irregular pulse
Difference in apical beat and radial pulse
Check for signs of thyroid disease and valvular disease
What would you see on an ECG for Atrial Fibrillation?
Uneven baseline with absent P waves
Irregular intervals between QRS complexes
Atrial Flutter = saw-tooth
What bloods would you do for Atrial Fibrillation?
Cardiac Enzymes TFT Lipid Profiles U&Es Mg2+ Ca2+
Why do we do U&Es, Mg2+ and Ca2+?
There is an increased risk of digoxin toxicity with hypokalaemia, hypomagnesaemia and hypercalcaemia
What might we see on an Echocardiogram in Atrial Fibrillation?
Mitral Valve disease
Left atrial dilation
Left Ventricular dysfunction
Structural Abnormalities
What do we do first when managing Atrial Fibrillation?
Try to treat any reversible causes (e.g. thyrotoxicosis, chest infection)
What are the two main components to AF management?
Rhythm Control
Rate Control
What do we do in Rhythm Control if it is > 48 hrs since onset of Atrial Fibrillation?
Anticoagulate for 3-4 weeks before attempting cardioversion
What do we do in Rhythm Control if it is < 48 hrs since onset of Atrial Fibrillation?
DC cardioversion (2 x 100 J, 1 x 200 J) Chemical cardioversion: flecainide or amiodarone
When is flecainide contraindicated?
If there is a history of Ischaemic Heart Disease
What’s the other step we do to control rhythm?
Prophylaxis against Atrial Fibrillation
What’s involved in Prophylaxis against Atrial Fibrillation?
Sotanol
Amiodarone
Flecainide
Consider pill-in-the-pocket (single dose of a cardioverting drug (e.g. flecainide) for patients with paroxysmal AF) strategy for suitable patients
What do we do to control rate in chronic AF?
Control ventricular rate with:
Digoxin
Veraparmil
Beta-Blockers
What ventricular rate do we aim for in AF management?
90 bpm
How do we stratify the risk of stroke in patients with Atrial Fibrillation?
CHADS-Vasc Score
What risk factors are included in the CHADS-Vasc Score?
Previous thromboembolic event Age > 75 years Hypertension Diabetes Vascular disease Valvular disease Heart Failure Impaired left ventricular function
How do we manage patients with a low risk of stroke?
Aspirin
What do we do to patients with a high risk of stroke?
Require anticoagulation with warfarin
What are the possible complications of Atrial Fibrillation?
Thromboembolism
Worsening of existing heart failure
What are the characteristics of Thromboembolism?
Embolic stroke risk of 4% per year
Risk is increased with left atrial enlargement or left ventricular dysfunction
What is the prognosis for patients with Atrial Fibrillation?
Chronic AF in a disease heart doesn’t usually return to sinus rhythm
