Atrial fibrillation Flashcards
Describe atrial fibrillation
supraventricular tachyarrhythmia
uncoordinated atrial contraction
irregular and frequently fast ventricular rate
What are the 5 AF patterns?
First diagnosed AF (AF that has not been diagnosed before)
Paroxysmal AF (self-terminating normally within 48 hours)
Persistent AF (AF that lasts longer than 7 days)
Long-standing persistent AF (continuous AF for >1 year)
Permanent AF (AF that is accepted by the patient and physician, no rhythm control interventions)
AF symptoms
palpitations
dyspnoea
chest tightness
fatigue/lethargy
sleeping disturbance
psychological effects
AF ECG signs
irregularly irregular heart rate
absent p waves
Cardiac causes of atrial fibrillation
ischaemic heart disease
hypertension
rheumatic heart disease
peri/myocarditis
Non-cardiac causes of atrial fibrillation
dehydration
endocrine causes (eg. hyperthyroidism)
infective causes (eg. sepsis)
pulmonary causes (eg. pneumonia or PE)
environmental toxins (eg. alcohol abuse)
electrolyte disturbances (eg. hypokalaemia, hypomagnesaemia)
ageing
obesity
sleep apnoea
Signs of AF
irregularly irregular pulse rate
single waveform on JVP (due to loss of a wave)
apical to radial pulse deficit (not all atrial pulses are mechanically conducted to ventricles)
variable intensity first heart sound on auscultation
What is fast AF?
ventricular rate >100bpm
normally needs some form of immediate treatment
What is the treatment for a patient in fast AF who is haemodynamically unstable?
immediate DC cardioversion
When should rate control not be offered in AF?
when AF has a reversible cause
heart failure primarily caused by AF
new onset AF
if rhythm control would be more suitable on clinical judgement
AF investigations
12-lead ECG
BP
Bloods - FBC, U&E, LFT, TFT, Coag
Echocardiogram
Holter monitoring - symptom/rhythm correlation, AF burden, ventricular rate control
What is a holter monitor?
a wearable device that records the heart’s rhythm
How is rate control offered in AF?
beta blockers (eg. bisoprolol) or rate-limiting calcium channel blocker (eg. diltiazem) should be initial monotherapy
consider digoxin monotherapy for people with non-paroxysmal AF only if they are sedentary
How does AF cause strokes?
blood pools in the atria
blood clot forms
whole or part of blood clot breaks off
blood clot travels to the brain and blocks a cerebral artery causing a stroke
What 2 methods can be used to achieve rhythm control in AF?
electrical cardioversion
pharmacological cardioversion
How and when is Flecainide used in AF?
can be given regularly or a ‘pill in the pocket’ for when symptoms occur
preferred in young patients with structurally normal hearts
What can Flecainide do to structurally abnormal hearts?
induce fatal arrhythmias
When is Amiodarone used in AF?
extremely effective in controlling rate and rhythm
lots of side effects
only usually given to older, sedentary patients
When is Sotalol used in AF? What sort of drug is it?
beta blocker with additional potassium channel blocker action
used for those who don’t meet the demographics for flecainide or amiodarone
Why should AF patients be anticoagulated?
risk of stroke
What does CHADS2VASc score measure?
stroke risk for patients with AF
How should CHADS2VASc2 score be interpreted?
men score >=1 need anticoagulation
women score >=2 need anticoagulation
What scoring system stratifies bleeding risk on anticoagulants?
HASBLED
What are the components of the HASBLED score?
Hypertension (1)
Abnormal renal/liver function (1 for each)
Stroke (previous) (1)
major Bleed (1)
Labile INR (1)
Elderly >65 (1)
Drugs/alcohol (1 for each)
What does the ORBIT score measure and what does it take into account?
risk of bleeding (similar to HASBLED)
sex
haemoglobin
age
bleeding history
renal function
concomitant use of antiplatelets
What anticoagulant is normally used for AF?
DOAC
- no monitoring
- generally lower bleeding risks
When would warfarin be used for anticoagulation in AF?
valvular AF
When can atrial ablation be used to treat AF?
when patient has uncontrolled symptoms and an identifiable locus in left atrium
Complications of AF
heart failure
systemic emboli (ischaemic stroke, mesenteric ischaemia, acute limb ischaemia)
bleeding (GI, intracranial)
