Atrial Fibrillation/Flutter Flashcards
Define atrial fibrillation
characterised by rapid, chaotic and ineffective atrial electrical conduction. Often subdivided into:
Permanent
Persistent
Paroxysmal
Permanent atrial fibrillation
continuous and lasts longer than 12 months
Persistent atrial fibrillation
If your irregular heartbeat episode lasts for more than a week
Paroxysmal atrial fibrillation
occurs when a rapid, erratic heart rate begins suddenly and then stops on its own within 7 days
Explain the aetiology and risk factors of atrial fibrillation
There may be no identifiable cause
Secondary causes lead to an abnormal atrial electrical pathway that results in AF
Systemic Causes
Thyrotoxicosis- excess thyrid hormone
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
Summarise the epidemiology of atrial fibrillation
VERY COMMON in the elderly
Present in 5% of those > 65 years
May be paroxysmal
Recognise the presenting symptoms of atrial fibrillation
Often ASYMPTOMATIC
Palpitations
Syncope (if low output)
Symptoms of the cause of AF
Recognise 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
Identify appropriate investigations for atrial fibrillation
ECG
Bloods
Echocardiogram
ECG
Uneven baseline with absent p waves
Irregular intervals between QRS complexes
Atrial flutter = saw-tooth
Bloods
Cardiac enzymes
TFT- thyroid function
Lipid profile
U&Es, Mg2+ and Ca2+
Because there is increased risk of digoxin toxicity with hypokalaemia, hypomagnesaemia and hypercalcaemia tf
Echocardiogram
Mitral valve disease
Left atrial dilatation
Left ventricular dysfunction
Structural abnormalities
Generate a management plan for atrial fibrillation
First and foremost, try to treat any reversible causes (e.g. thyrotoxicosis, chest infection)
There are TWO main components to AF management:
RHYTHM CONTROL
RATE CONTROL
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
Prophylaxis against AF
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 patients
RATE CONTROL
Chronic (Permanent) AF
Control ventricular rate with:
Digoxin
Verapamil
Beta-blockers
Aim for ventricular rate ~ 90 bpm
STROKE RISK STRATIFICATION
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
Identify the possible complications of atrial fibrillation
THROMBOEMBOLISM
Embolic stroke risk of 4% per year
Risk is increased with left atrial enlargement or left ventricular dysfunction
Worsening of existing heart failure
Summarise the prognosis for patients with atrial fibrillation
Chronic AF in a diseased heart does not usually return to sinus rhythm
