AF Flashcards
what is AF?
Supraventricular tachyarrhythmia
*Irregular, disorganised electrical activity in the atria
*Rapid firing impulses disorganised atrial
depolarisation and ineffective atrial contractions
*AV node receives more electrical impulses than it can conduct irregular ventricular rhythm
what is the ventricular rate of untreated AF?
160-180 beats per minute (usually slower in elderly)
what can irregular atrial contractions result in?
blood stasis
clot formation
what is paroxysmal AF?
Episodes lasting longer than 30 seconds but less than 7 days (often less than 48 hours) that are self-terminating and recurrent
what is persistent AF?
Episodes lasting longer than 7 days
*Or less than 7 days but requiring cardioversion
*Spontaneous termination of the arrhythmia is unlikely to occur after
this time
define permanent AF?
–Fails to terminate using cardioversion,
–Terminated but relapses within 24 hours,
–Longstanding AF (usually >1 year) in which cardioversion has not been
indicated or attempted (sometimes called accepted permanent AF)
what are the common causes of AF?
Hypertension, ischaemic heart disease, myocardial infarction, valvular
heart disease and hyperthyroidism
does prevalence rise with age?
At the age of 40, we all have a 1 in 4 life time risk of developing AF (The Framingham Heart Study)
why does having AF matter?
*Stroke and thromboembolism risk
–x5 times higher in AF
*Heart Failure
*Tachycardia-induced cardiomyopathy and critical
cardiac ischemia
*Reduced quality of life
*Increased risk of mortality
what are the main symptoms of AF?
–Breathlessness
–Palpitations
–Chest discomfort
–Syncope or dizziness
–Stroke or transient ischaemic attack
how do you formulate a diagnosis of AF?
Manual pulse palpation to assess for irregular
pulse
*12 lead ECG
*24 hour ambulatory ECG if paroxysmal AF
suspected
*Echocardiography
what are the possible differential diagnosis?
*Atrial flutter — characterized by saw-tooth pattern of regular
atrial activation on the ECG
*Atrial extrasystoles — common & may cause an irregular pulse
*Ventricular ectopic beats
*Sinus tachycardia — SR with more than 100 bpm
*Supraventricular tachycardias, including atrial tachycardia,
AVNRT tachycardia, and WPW
*Multifocal atrial tachycardia.
what management would you do with a person presenting with AF?
Identify underlying cause
*Treat arrhythmia
*Assess stroke risk
*Assess bleeding risk
*Monitoring and follow up
*Counselling of condition and medication
what are the two types of treatment regimes?
rate and rhythm control?
what is rate control?
–First line unless suitable for rhythm control/ investigations for rhythm ongoing
–Beta blocker (not sotalol)
–Or rate limiting calcium channel blocker (diltiazem or verapamil)
–Digoxin monotherapy
*Consider if very little physical exercise or other options ruled out
what is rhythm control? who should it be considered in?
New onset AF (<48 hours)
–Reversible cause (e.g. chest infection)
–HF caused/worsened by AF
–Atrial flutter suitable for ablation
–Clinician judgement of patient
–May take time to determine if suitable for rhythm- in interim give rate
how should someone with acute AF be managed?
Consider either pharmacological or electrical cardioversion for new-onset AF who will be treated by rhythm control
anticoag
bleed risk
what should you offer in cardioversion?
–Flecainide or amiodarone if there is no evidence of structural or ischaemic
heart disease or
amiodarone if there is evidence of structural heart disease.
–If >48 hrs (or uncertain) and long-term rhythm control, delay cardioversion
until maintained on therapeutic anticoagulation for a minimum of 3 weeks.
During this period offer rate control as appropriate
how is rhythm control implemented?
Specialist management
–Initiated in secondary care but often continued in
primary care
*Electrical cardioversion
*Pharmacological cardioversion
–Amiodarone (revise monitoring, adverse effects and interactions)
who are beta blockers avoided in?
Normally avoid in people with history of obstructive airways disease
what dose of atenolol should be given?
–50-100mg daily
–Monitor HR and BP to titrate against response
what are the adverse effects of BBs?
Bradycardia and hypotension
*Cold extremities
*Disturbed sleep and nightmares
–less likely with water soluble agents such as atenolol
*Sexual dysfunction
*Can cause hypoglycaemia or hyperglycaemia in patients +/-
diabetes.
*Mask signs of a hypoglycaemia
*Withdrawal effects
*Fatigue
what CCBs are used?
Rate limiting CCB used in AF
–Diltiazem and verapamil
*Off label use of diltiazem
what is the consequence of CCBs and statins?
Interaction with other medication
–Simvastatin capped at 20mg
when should you avoid CCBs?
avoid in HF as depresses cardiac function and can exacerbate symptoms
what are some side effects of CCBs?
Headache, dizziness, hypotension,
bradycardia (refer to BNF for additional)
when is flecainide given?
Infrequent paroxysms and few symptoms induced by known precipitants (alcohol, caffeine)
when should you assess stroke risk?
–Symptomatic or asymptomatic paroxysmal,
persistent or permanent atrial fibrillation
–Atrial flutter
–A continuing risk of arrhythmia recurrence after
cardioversion back to sinus rhythm or catheter
ablation.
when should bleed risk be assessed?
- Starting anticoagulation
- Reviewing people taking anticoagulants
how is bleed risk assessed?
ORBIT
when should you offer anticoagulation in AF?
chadvasc score of 2+ and men of 1
when is a DOAC contraindicated?
not tolerated or not suitable in people
with AF, offer a vitamin K antagonist
when may anticoagulation treatment not be worth it?
if patient is at an increased risk of bleeds
how should you give anticoagulation in acute AF?
Heparin at initial presentation and continue until appropriate anticoagulant started
when can you offer oral anticoagulation in confirmed diagnosis of af?
*Stable sinus rhythm is not successfully restored within the same 48-hour
period after onset
*High risk of AF recurrence (history of failed cardioversion, structural heart
disease, prolonged AF (>12 months), or previous recurrences
*Based on CHADSc-VASc
