atrial fibrillation Flashcards
atrial fibrillation (AF)
supraventricular tachyarrhythmia resulting from irregular and disorganised electrical activity and ineffective atrial contraction
first-diagnosed AF
not been diagnosed before regardless of symptom status, temporal pattern or duration
paroxysmal AF
terminates spontaneously within a week or with intervention and atrial remodelling has not yet occurred
persistent or continuous AF
episodes that are not self-terminating and lasts at least a year with treatment being an option for selected patients
permanent AF
atrial remodelling has occurred and lasts more than a year with treatment not being an option
AF pathophysiology (5)
electrical signals cross atria at the same time, atria quiver causing blood to pool and form a clot, some signals reach ventricles which contract irregularly, emptying of blood is impaired
AF complications (3)
thromboemboli, acute heart failure, tachycardia
thromboemboli complications (3)
stroke via carotid artery, ischaemic colitis via mesenteric arteries, acute limb ischaemia via femoral artery
acute heart failure complications (2)
pulmonary oedema via atrial regurgitation into pulmonary veins or shock via decreased cardiac output
tachycardia complication
dilated cardiomyopathy
stroke risk in AF patients
5-6 times greater than people with normal sinus rhythm
stroke risk after anticoagulant therapy
reduced by 2/3 (can prevent 6/10 strokes)
AF causes
PIRATES - pulmonary diseases, ischaemia, remodelling of atria, alcohol, thyrotoxicosis, electrolyte imbalance, sepsis
AF cardiac causes
CAD/MI, CHF, mitral stenosis (valvular AF)
how does CAD/MI cause AF? (4)
cardiac ischaemia, cardiac fibrosis, atrial remodelling, re-entrant circuits
how does CHF cause AF?
increased left atrial pressure
how does mitral stenosis cause AF? (4)
blocked blood flow to ventricles, increased left atrial pressure, atrial remodelling, re-entrant circuits
AF non-cardiac causes (6)
alcohol, electrolyte imbalances, pulmonary diseases, sepsis, thyrotoxicosis
how do electrolyte imbalances cause AF?
ectopic firing of atrial cells
how do pulmonary diseases cause AF? (2)
hypoxia, ectopic firing of atrial cells
how does alcohol, sepsis and thyrotoxicosis cause AF? (3)
increased catecholamine release, beta1-adrenoceptor activation, ectopic firing of atrial cells
AF symptoms (7)
asymptomatic, chest discomfort, dyspnea, fatigue, palpitations, stroke, syncope
AF investigations
ECG, echocardiogram, bloods for electrolytes and TFTs
AF ECG
variable R to R interval and rapid ventricular rate
AF echocardiogram
left atrial dilation and/or thrombus formation
AF blood tests
hypokalemia, hypomagnesemia, hyperthyroidism
CHADS-VASc purpose
assesses stroke risk
CHADS-VASc score >2
high risk of stroke, offer anticoagulants
CHADS-VASc score = 1
consider anticoagulants
CHADS-VASc score = 0
avoid anticoagulants and use aspirin
ORBIT scoring
assesses bleeding risk
AF management (3)
rate control, rhythm control (for acute AF), anticoagulation
acute AF with unstable HD management
emergency DCC
acute AF with stable HD < 48 hours onset (3)
anticoagulation, rate control or DCC
acute AF with stable HD > 48 hours onset (2)
anticoagulation, rate control
rate control drugs
amiodarone, beta blockers (for HF), rate-limiting calcium channel blockers (for asthma or diabetes), digoxin (for persistent or permanent AF)
rhythm control
direct current cardioversion (within 4 weeks) and/or anti-arrhythmics
anticoagulation drugs
DOACs (for non-valvular AF), vitamin K antagonists/warfarin (for valvular or non-valvular AF with CKD), heparin
supraventricular tachycardia (SVT) treatment
IV adenosine with myocardial nuclear imaging
bradyarrhythmia treatment
atropine
ventricular tachycardia treatments (2)
IV magnesium sulphate, beta blocker, atrial pacing (avoid anti-arrhythmics)
