Flashcards in Week 5 Deck (14)
What is atrial fibrillation?
Chaotic, synchronous electrical activity in the atria
What is more common atrial flutter or fibrillation?
What does atrial fibrillations stem from?
The firing of a number of impulses from a re-entry circuit
What is the atrial rate of fibrillation?
400-600 bpm - considered to quiver
Is ventricular rate regular or irregular in atrial fibrillation?
Typically irregularly irregular
What can atrial fibrillation be classified as?
1. permanent (no expectation of restoring sinus rhythm)
2. persistent (no background intervening sinus rhythm)
3. paroxysmal (sudden bursts of atrial fibrillation)
What testing is strongly advised in an individual with atrial flutter?
Can atrial fibrillation lead to hypotension?
Yes, as atrial kick is lost and so SV is reduced
What is uncontrolled atrial fibrillation?
Ventricular response is more than 100bpm
How does atrial fibrillation increase the risk of stroke, pulmonary embolism?
The quivering atrial results in the 'pooling' of blood which increase the likelihood of thrombus formation
What happens during atrial fibrillation?
When several ectopic sites in the atria fire, the atria cannot depolarise in an organised fashion and small sections are activated individually
What prevents the ventricular rate being the same?
The fact tissue may be in refractory and the delay in conduction of 0.04 seconds within the AV node
What 3 mechanisms are atrial arrhythmias thought to be caused by?
enhanced automaticity, re-entry circuit, after-depolarisation