Atrial Fibrillation Basics Flashcards
What is atrial fibrillation?
Cardiac arrhythmia
Characterised by disorganised electrical activity within the atria
Results in ineffective atrial contraction and irregular ventricular contraction
What are the types of atrial fibrillation?
Paroxysmal - terminate within 7 days
Persistent - episodes last longer than 7 days
Permanent - decision not to treat
What is AF a type of?
Supraventricular cardiac arrhythmia - originates above the ventricles
Where does AF originate from?
Left atrial myocytes and extends around the pulmonary vein
What does the chaotic electrical activity cause?
Intermittently conducted through AVN - gives rise to irregularly irregular ventricular rate
What is the main cause of AF?
Triggers typically cause the atria to stretch - changes their electrical properties
What are cardiac causes of AF?
Hypertension
Ischaemic heart disease
Heart failure with reduced ejection fraction
Structural pathology
Congenital heart disease
Atrial or ventricular dilatation / hypertrophy
Pre-excitation syndromes
Sick sinus syndrome
Inflammatory conditions
Infiltrative conditions
What are non-cardiac causes of AF?
Acute infection
Electrolyte imbalance
Pulmonary embolism
Thyrotoxicosis or hypothyroidism
Diabetes
What are the risk factors for AF?
Gender
Caucasian ethnicity
Age
Alcohol
Smoking
Obesity
Co-morbidities
What are typical symptoms of AF?
Breathlessness
Chest discomfort
Palpitations
Light headedness
Reduced exercise tolerance
Syncope
What do you find on clinical examinations?
Irregularly irregular pulse
Radial-apical deficit; each ventricular contraction may not be sufficiently strong enough to transmit a pulse to radial artery
Raised jugular venous pressure
Added heart sound
Crackles on chest auscultation
Ankle swelling
What do you find on an ECG?
Irregularly irregular rhythm
Absent p wave
What other examinations do you do?
FBC - to see for any causes
U + E - to see for any causes
LFT - establish baseline hepatic function before giving anticoagulants
TFT - assess for thyroid dysfunction
CRP - to see for any causes
Clotting screening
NT-proBNP - underlying heart failure