Cardiology - Atrial Fibrillation Flashcards
Why can AF increase the risk of thrombus formation?
Uncoordinated atrial activity causing blood to stagnate in the atria
5x higher risk in AF for a stroke
What lifestyle factors can cause AF?
Alcohol
Caffeine
What are the most common causes of AF?
SMITH
Sepsis
Mitral valve pathology
Ischaemic heart disease
Thyrotoxicosis
Hypertension
What is the key examination finding in AF?
Irregularly irregular pulse
May also be ventricular ectopics
What happens to ventricular ectopics during exercise?
Ventricular ectopics disappear when heart rate is high enough and heart rate becomes normal
What are the ECG findings for AF?
Absent P waves
Narrow QRS complex tachycardia
Irregularly irregular
What is paroxysmal atrial fibrillation?
Episodes of AF that reoccur and spontaneously resolve back to sinus rhythm
Episodes last between 30 seconds and 48 hours
What investigations are used for suspected paroxysmal AF?
24 hour ambulatory ECG (Holter monitor)
Cardiac event recorder (lasts 1-2 weeks)
What is valvular atrial fibrillation?
AF with significant mitral stenosis or a mechanical heart valve
Assumption is that AF has been caused by valvular issue
How is AF managed?
Rate or rhythm control
Anticoagulation to prevent strokes
How do ventricles fill in AF?
Suction and gravity as atrial contractions are not coordinated
So higher heart rate less time for filling, reducing CO
Rate control to bring heart rate down to increase filling
When should patients with AF not be given a rate control as first line?
A reversible cause for AF
New onset within 48 hours
Heart failure caused by AF
Symptoms despite being controlled well
What options are used for rate control in AF?
Beta blocker (atenolol or bisoprolol)
Calcium-channel blocker (diltiazem or verapamil)
Digoxin
When is rhythm controlled offered to AF patients?
Reversible cause
New onset within 48 hours
Heart failure due to AF
Symptoms despite being controlled well
What options are used for rhythm control?
Cardioversion
Long-term rhythm control with medications