Atrial Fibrillation Flashcards
what is atrial fibrillation happen
contraction of atria is uncoordinated, rapid and irregular
due to disorganised electrical activity that ovverides normal organised activity from SA nose
leads to irregular conduction of electrical impulses to ventricles
what does irregular conduction of electrical impulses to ventricles result in
- irregularly irregular ventricular contractions
- tachycardia
- heart failure - poor filling of ventricles during diastole
- risk of stroke
presenting symptoms
palpitations
SOB
syncope
2 differentials for an irregularly irregulaer pulse
AF
ventricular ectopics
ECG findings in AF
absent P waves,
narrow QRS complex tachycardia,
irregularly irregular ventricular rhythm,
valvular AF
when patients with AF also have mod-severe mitral stenosis or a mechanical heart valve
most common causes of AF
sepsis, mitral valve pathology, IHD, thyrotoxicosis, htn
2 principles of treating AF
rate or rhythm control
anticoagulation
All patients with AF should have rate control as first line unless…
- reversible cause for AF
- new onset AF (<48hrs)
- AF causing heart failure
- remain symptomatic depsite effective rate controlling
options for rate control
- beta blocker
- CCB
- digoxin (only sedentary people)
when can rhythm control be offered to people wih AF
- reversible cause
- new onset (<48hrs)
- AF causing heart failure
- remain symptomatic depstite effective rate control
aim of rate control
to get heart rate below 100 to extend the time during diastole when ventricles can fill w bloo d
aim of ryhtm control
return the patient to normal sinus rhythm
can be done via single cardioversion or medicalluy
immediate cardiovesion if
the AF has been present <48hrs or they are severely haemodynamically unstable
delayed cardioversion if…
AF has been present >48hrs and they are stable
2 options for cardioversion
pharmacological
electrical
pharmacological cardioversion
flecanide or
amiodarone (if structural heart disease)
electrical cardioversion
rapidly shock the heart back into sinus rhythm
involves sedation/GA and using defib to deliver controlled shocks
long term medical rhythm control
- beta blockers
- dronedarone
- amiodarone
paroxysmal AF
the AF comes and goes in episodes, usually no more than 48hrs
should still be anticoagulated based on CHADVASCs score
warfarin
vitamin K antagonist
prolongs prothrombin time
how to assess how anticoagulated a pt is by warfarin
measure INR
what is INR
calculation of how the prothrombin time of the patient compares with the prothrombin time of a normal healthy afult
warfarin monitoring
close monitoring of INR and frequent dose adjustments
DOACs example
apixiban
dabigantran
rivaroxaban
DOAC advantages over warfarin
- no monitoring required
- no major interaction problems
CHADSVASC score
tool for assessing wheather a patient with AF should be started on anticoagulation
CHADVASC score: 0
no anticoagulation
CHADVASC score: 1
consider anticoagulation
CHADVASC score: >1
offer anticoagulation
HAS-BLED
assessment tool for establishing a patient’s risk of major bleeding whilst on anticoagulation
