AF Flashcards
What is AF?
Where the contraction of the atria is uncoordinated, rapid and irregularly
- This due to disorganised electrical activity that overrides the normal, organised activity from the sinoatrial node
- An ECG will show an absence of p waves (this reflects the lack of coordinated atrial electrical activity)
What complications can AF cause?
Irregularly irregular ventricular contractions
Tachycardia
Heart failure due to poor filling of the ventricles during diastole
Risk of stroke
(Tendency for blood to collect in the atria and form blood clots. These clots can become emboli, travel to the brain and block the cerebral arteries causing an ischaemic stroke)
How does AF present?
Breathlessness/dyspnoea Palpitations Syncope (dizziness or fainting) Chest discomfort Stroke/TIA
How may AF be diagnosed?
Perform manual pulse palpation - look for irregular pulse for underlying AF
ECG - whether symptomatic or not in suspected irregular pulse (AF)
If paroxysmal AF is suspected, use 24-hr ambulatory monitoring or an event recorder ECG
Perform transthoracic echocardiography (TTE) in people with AF if cardioversion is being considered. If further investigation is needed, perform transoesophageal echocardiography (TOE)
What does CHA2DS2VASc stand for?
C – Congestive heart failure H – Hypertension A2 – Age >75 (Scores 2) D – Diabetes S2 – Stroke or TIA previously (Scores 2) V – Vascular disease A – Age 65-74 S – Sex (female)
In whom should the CHA2DS2VASc stroke risk score be used?
Symptomatic or asymptomatic paroxysmal, persistent or permanent AF
Atrial flutter
A continuing risk of arrhythmia recurrence after cardio version back to sinus rhythm
Score of 0 = low risk, NO anticoagulation; 1 = low-moderate risk, consider anticoagulation; ≥2 = moderate-high risk, offer anticoagulation
How is ‘HAS-BLED’ used and what for?
Assess risk in people who are starting or have started anticoagulation
H – Hypertension A – Abnormal renal and liver function S – Stroke B – Bleeding L – Labile INRs (whilst on warfarin) E – Elderly D – Drugs or alcohol
What anti-coagulants may be prescribed and to whom?
Offer to all patients with CHA2DS2-VASc Score ≥2, taking bleeding risk into account. Consider for men with score of 1
Apixaban Dabigatran etexilate Rivaroxaban Vitamin K antagonist - e.g. warfarin - Therapeutic range of INR should be 2-3 - Reassess anticoagulation if: ‣ 2 INR values >5 OR 1 INR value >8 ‣ 2 INR values <1.5
When should rate control be offered in AF as first-line strategy?
There is reversible cause of AF
AF is new-onset (within last 48 hours)
AF is causing HF
Remain symptomatic despite being effectively rate controlled
What medications can be given for rate control?
ß-blocker e.g. bisoprolol, carvedilol
Rate limiting CCB (calcium channel blocker) e.g. diltiazem, verapamil
Digoxin - monotherapy for people with non-paroxysmal AF, only if they are sedentary (little to no exercise)
(Amiodarone is NOT suitable for long-term rate control)
How may rhythm control be managed?
Consider pharmacological and/or electrical cardioversion for AF where rate-control has been unsuccessful in managing symptoms
What does electrical cardioversion involve?
“Cardioversion” event that puts the patient back in to sinus rhythm or long term medical rhythm control that sustains a normal rhythm
Used when AF has lasted > 48 hours (and appropriately anti-coagulated)
- Start amiodarone 4 weeks before and continues up to 12 months after electrical cardioversion
What can be given for pharmacological cardioversion?
ß-blockers as FIRST-LINE
Dronedarone as SECOND-LINE - used for maintenance of normal sinus rhythm after successful cardioversion (WITHOUT LV impairment or HF)
Amiodarone - useful in patients with LV impairment or HF
How may an acute presentation of AF be managed?
Emergency electrical cardioversion - in life-threatening haemodynamic instability (where BP and HR is unstable)
If patient is stable and AF started <48 hours ago offer RATE OR RHYTHM CONTROL
- For rhythm:
‣ Flecainide
‣ Amiodarone (drug of choice in patients WITH structural heart disease)
‣ Electrical cardioversion
- For rate: ß-blockers (or CCB?)
Anticoagulation - Offer heparin if no contraindication
- Continue until assessment has been made and appropriate anti-thrombotic therapy has been started
What is paroxysmal AF?
When the AF comes and goes in episodes, usually not lasting more than 48 hours
• Patients should still be anti coagulated based on CHADSVASc score
