AF

Question 1

definition

Answer 1

Characterized by rapid, chaotic and ineffective atrial electrical conduction. Often subdivided into: ‘permanent’, ‘persistent’ and ‘paroxysmal’.

Question 2

causes

Answer 2

Systemic causes: Thyrotoxicosis, hypertension, pneumonia, alcohol.
Heart: Mitral valve disease, ischaemic heart disease, rheumatic heart disease, cardiomyopathy, pericarditis, sick sinus syndrome,1 atrial myxoma. Lung: Bronchial carcinoma, pulmonary embolism.

Question 3

investigations

Answer 3

ECG: Uneven baseline (fibrillations) with absent P waves, irregular QRS complexes. If there is a saw-tooth baseline, consider if there is atrial flutter.2
Blood: Cardiac enzymes, TFT, lipid profile, U&E, Mg, Ca (risk of digoxin toxicity increased with hypokalaemia, hypomagnesaemia or hypercalcaemia).
Echocardiogram: To assess for mitral valve disease, left atrial dilation, left ventricular dysfunction or structural abnormalities.

Question 4

symptoms

Answer 4

Often asymptomatic. Some patients experience palpitations or syncope. Symp- toms of the cause of the AF.

Question 5

management

Answer 5

Treat any reversible cause (e.g. thyrotoxicosis, chest infection). Specific treatment strategy focuses on:
1. Rhythm control:
If the AF is >48h from onset, anticoagulate (at least 3–4 weeks) before attempting cardioversion.
DC cardioversion: Synchronized DC shock (2 x 100 J, 1 x 200 J).
Chemical cardioversion: Flecainide (contraindicated if there is history of ischaemic heart disease) or amiodarone.
Prophylaxis against AF: Sotalol, amiodarone or flecainide.

2. Rate control:
   Chronic ‘permanent’ AF: Ventricular rate control with digoxin, verapamil and/or b- blockers. (Aim for rate of about 90 BPM)
3. Stroke risk stratification:
   Low-risk patients can be managed with aspirin, and high-risk patients require anticoagulation with warfarin.
   Risk factors indicating high risk are previous thromboembolic event, age more than or equal to 75 years with hypertension, diabetes or vascular disease, and/or clinical evidence of valve disease, heart failure or impaired left ventricular function.

Question 6

complications

Answer 6

thromboembolism

Question 7

prognosis

Answer 7

chronic AF in diseased heart doesn’t usually go back to normal sinus rhythm