Atrial Fibrilation Flashcards
Pathophysiology of AF
Contraction of atria is uncoordinated, rapid and irregular, due to disorganised electrical activity that overrides normal SAN
Presentation of AF
Palpitations, SOB, syncope, symptoms of associated conditions
How does AF impact the ventricles
Irregular conduction to the ventricles resuling in irregular contractions, tachycardia, heart failure (poor filling of ventricles) and risk of stroke
Differentials for irregularly irregular pulse
Atrial fibrilation and ventricular ectopies
AF appearance on ECG
Absent P waves, narrow QRS complex tachycardia, irregularly irregular ventricular rhythm
What is valvular AF
Patients with AF who also have moderate or severe mitral stenosis or mechanical heart valve.
Most common causes of AF
Sepsis, mitral valve pathology, ischaemic heart disease, thyrotoxicosis, hypertension
Two principles of treating AF
Rate or rhythm control.
Anticoagulation to prevent stroke
Options for rate control
Beta blocker
Calcium channel blocker
Digoxin
Eg of beta blocker for AF
Atenolol 50-100mg
Eg of calcium channel blocker
Diltiazem
Which patients should not have rate control first line
If AF is reversible, if AF is new onset, if it is causing HF, if they remain symptomatic despite rate being controlled
What is the aim of rhythm control
Return patient to normal sinus rhythm by single cardioversion or long term medical control
When is immediate cardioversion given
If AF has been present for less than 48 hours or severely haemodynamically unstable
When is delayed cardioversion given
If AF has been present for more than 48 hours and they are stable
What should happen to patients while they wait for cardioversion
Put on rate control and anticoagulated for minimum of 3 weeks prior
Pharmacological cardioversion options
Flecanide or amiodarone (structural heart disease)
Aim of electrical cardioversion
Rapidly shock the heart back into sinus rhythm, involving sedation or general anaesthetic
Options for long term medical rhythm control
beta blockers first line
dronedarone
amiodarone (HF or LV dysfunction)
What is paroxsymal AF
When AF comes and goes in episodes, usually not lasting more than 48 hours
What drug is used for the ‘pill in the pocket’ approach
Flecanide
How might paroxsymal AF be managed
‘Pill in the pocket’ approach
When can flecanide not be given
In atrial flutter
Cardiac causes of AF
Ischaemic heart disease, HTN, rheumatic heart disease, myocarditis
Non-cardiac causes of AF
Dehydration, endocrine (hyperthyroidism), infective (sepsis), toxins (alcohol), pulmonary (PE, pneumonia), hypokalaemia, hypomagnesaemia
Classification of AF
Acute = <48 hours
Paroxysmal = <7 days
Persistent = >7 days but amendable to CV
Permanent = >7 days not amendable to CV
