Atrial Fibrillation/Flutter

Question 1

Definition

Answer 1

Characterised by rapid, chaotic and ineffective atrial electrical conduction.

Often subdivided into:
o Permanent
o Persistent
o Paroxysmal

Question 2

Aetiology/risk factors (systemic)

Answer 2

· There may be no identifiable cause

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

· Systemic Causes
o Thyrotoxicosis
o Hypertension
o Pneumonia
o Alcohol

Question 3

Aetiology/risk factors (heart)

Answer 3

· Heart Causes

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

Question 4

Aetiology/risk factors (lung)

Answer 4

· Lung Causes

o Bronchial carcinoma
o PE

Question 5

Epidemiology

Answer 5

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

Question 6

Presenting symptoms

Answer 6

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

Question 7

Signs on physical examination

Answer 7

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

Question 8

Investigations (bloods)

Answer 8

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

Question 9

Investigations (other)

Answer 9

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

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

Question 10

Management plan (rhythm control)

Answer 10

First and foremost, try to treat any reversible causes (e.g. thyrotoxicosis, chest infection)

There are TWO main components to AF management:

· RHYTHM CONTROL

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

o 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

o 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

Question 11

Management plan (rate control)

Answer 11

o Chronic (Permanent) AF

· Control ventricular rate with:
§ Digoxin
§ Verapamil
§ Beta-blockers

· Aim for ventricular rate ~ 90 bpm

Question 12

Management plan (stroke risk stratification)

Answer 12

o LOW RISK patients can be managed with aspirin

o HIGH RISK patients require anticoagulation with warfarin

o This is based on the CHADS-Vasc Score

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

Question 13

Possible complications

Answer 13

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

· Worsening of existing heart failure

Question 14

Prognosis

Answer 14

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