Atrial Fibrillation Flashcards
What is atrial fibrillation?
Where the contraction of the atria is uncoordinated, rapid and irregular. This is due to disorganised electrical activity that overrides the normal, organised activity from the SA node.
What is the common ECG change seen in atrial fibrillation?
Absent P waves
Narrow QRS Complex Tachycardia
Irregularly irregular ventricular rhythm
What are the other complications of atrial fibrillation?
- Irregularly irregular ventricular contractions
- Tachycardia
- Heart failure due to poor filling of the ventricles during diastole
- Risk of stroke - clots/embolism
- Palpitations
- Shortness of breath
- Syncope (dizziness or fainting)
- Symptoms of associated conditions (e.g. stroke, sepsis or thyrotoxicosis)
What is a major risk factor following atrial fibrillation?
Increased stroke risk through clot formation and embolism travelling to block cerebral arteries.
What are the causes of atrial fibrillation?
Sepsis Mitral Valve Pathology (stenosis or regurgitation) Ischemic Heart Disease Thyrotoxicosis Hypertension
What are the 4 types of atrial fibrillation?
First detected episode
Paroxysmal
Persistent
Permanent.
What is paroxysmal atrial fibrillation?
Recurrent episodes when a patient has 2 or more episodes of AF. If episodes of AF terminate spontaneously then the term paroxysmal AF is used. Such episodes last less than 7 days (typically < 24 hours).
What is persistent atrial fibrillation?
If the arrhythmia is not self-terminating then the term persistent AF is used. Such episodes usually last greater than 7 days
What is permanent atrial fibrillation?
Continuous atrial fibrillation which cannot be cardioverted or if attempts to do so are deemed inappropriate. Treatment goals are therefore rated control and anticoagulation if appropriate
What are two ways to manage atrial fibrillation?
Rate/rhythm control
Reducing stroke risk (Anticoagulants given)
NICE guidelines (2014) suggest all patients with AF should have rate control as first line; what are the exemptions to this?
- Reversible cause for their AF
- Their AF is of new onset (<48 hours)
- Their AF is causing heart failure
- They remain symptomatic despite being effectively rate controlled
What are the options for rate control in atrial fibrillation?
Beta blocker is first line
Calcium-channel blocker
Digoxin
What calcium channel blocker is not used in atrial fibrillation patients with heart failure?
Diltiazem should not be used as a calcium channel blocker in heart failure patients with atrial fibrillation
When is rhythm control used in atrial fibrillation patients?
- Reversible cause for their AF
- Their AF is of new onset (<48 hours)
- Their AF is causing heart failure
- They remain symptomatic despite being effectively rate controlled
What are the two ways that rhythm control is used in AF?
A single “cardioversion” event that puts the patient back in to sinus rhythm or long-term MEDICAL rhythm control that sustains a normal rhythm.
There is a choice between immediate cardioversion or delayed cardioversion in AF (rhythm control): when can IMMEDIATE cardioversion be used?
if the AF has been present for less than 48 hours or they are severely haemodynamically unstable.
There is a choice between immediate cardioversion or delayed cardioversion in AF (rhythm control): when can DELAYED cardioversion be used?
if the AF has been present for more than 48 hours and they are stable.
What should be done in patients prior to receiving delayed cardio version for AF (rhythm control)?
Patient should be anticoagulated for a minimum of 3 weeks prior to cardioversion.
Why is anticoagulation given prior to receiving delayed cardioversion?
Because during the 48 hours prior to cardioversion they may have developed a blood clot in the atria and reverting them back to sinus rhythm carries a high risk of mobilising that clot and causing a stroke.
There are two pharmacological options for cardioversion (rhythm control) in AF; what are they?
- Flecainide if no structural heart disease
2. Amiodarone (if patient has structural heart disease)
What are the two ways cardioversion is attempted in AF patients?
- Pharmacological cardioversion
2. Electrical cardioversion
Patients receiving pharmacological cardioversion are given drugs based on the presence of structural heart disease; what are the two drugs?
Flecainide if no structural heart disease
Amiodarone (if patient has structural heart disease)
What is the CHA2DS2-VASc score?
Tool for assessing whether a patient with atrial fibrillation should be started on anticoagulation. Assesses for stroke risk
Following a stroke or TIA in AF, what drugs can be given as anticoaguluants?
Warfarin OR a direct thrombin OR factor Xa inhibitor
