Atrial fibrillation Flashcards
Presentation of AF
Often asymptomatic
Palpitations
SOB
Syncope
Symptoms of associated conditions (e.g. stroke, sepsis or thyrotoxicosis)
Irregularly irregular pulse
ECG - absent P waves, irregularly irregular, narrow complex tachycardia
Results from AF
Irregularly irregular ventricular contractions
Tachycardia
Heart failure due to poor filling of the ventricles during diastole
Risk of stroke - due to tendency for blood to pool in the atria and form clots which can form emboli and block cerebral arteries
Pathophysiology of AF
Disorganised electrical activity causing uncoordinated, rapid and irregular contraction of the atria
Differentials for an irregularly irregular pulse
Atrial fibrillation
Ventricular ectopics
These can be differentiated on ECG.
Ventricular ectopics disappear when the heart rate gets over a certain threshold. Therefore a regular heart rate during exercise suggests a diagnosis of ventricular ectopics.
Most common causes of AF
Sepsis Mitral Valve Pathology (stenosis or regurgitation) Ischemic Heart Disease Thyrotoxicosis Hypertension
Principles of treating AF
Rate vs rhythm control
Anticoagulation
Rate control when…
All patients with AF should have this as first line unless:
- There is a reversible cause of their AF
- Their AF is of new onset (<48h)
- AF is causing heart failure
Rate control medication options
Beta-blocker - first line
CCB - if BB contraindicated/not tolerated, not in heart failure
Digoxin - only in sedentary patients usually
Rhythm control when…
There is a reversible cause for their AF
Their AF is of new onset (<48 hours)
Their AF is causing heart failure
Rhythm control options
Cardioversion vs long-term medical rhythm control
Cardioversion can be immediate (within 48h onset or severely haemodynamically unstable) or delayed (AF present for more than 48h and stable)
-Can be pharmacological or DC
Medical cardioversion:
- Normal heart - flecainide first line
- Structural heart disease - amiodarone
DC cardioversion under sedation/GA
Long term medical rhythm control:
- Beta blockers are first line for rhythm control
- Dronedarone is second line for maintaining normal rhythm where patients have had successful cardioversion
- Amiodarone is useful in patients with heart failure or left ventricular dysfunction
What should be done in delayed cardioversion?
Patient should be anticoagulated for 3w before the cardioversion
If AF and haemodynamically unstable
Senior help
Immediate DC cardioversion
Other medications to start in AF
Anticoagulation in rate controlled patients
Based on CHADSVASC and HASBLED/ORBIT scores
CHADSVASC >1 offer anticoagulation
