Wk 12: Atrial fibrillation Flashcards
Define atrial fibrillation
Supraventricular tachyarrhythmia
What is the ventricular rate of untreated AF?
160-180 bpm
Define paroxysmal AF
- Lasts longer than 30 secs + less than 7 days
- Self terminating + recurrent
Define persistent AF
- Lasts longer than 7 days
- Or less than 7 days but requires cardioversion
- Spontaneous termination unlikely to occur
Define permanent AF
- Fails to terminate using cardioversion
- Terminated but relapses w/in 24 hrs
- > 1 year where cardioversion = not indicated or attempted
What are the cardiac causes of AF?
- Congestive HF
- Atrial/ventricular hypertrophy
- Wolf-parkinson-white syndrome
- Pericarditis
- Myocarditis
What are the non-cardiac causes of AF?
- Acute infection
- Diabetes
- Electrolyte depletion
- Cancer
Which medications cause AF?
- Thyroxine
- Bronchodilators
What are the complications of AF?
- x5 risk of stroke + thromboembolism
- HF
- Tachycardia-induced cardiomyopathy
What are the main symptoms of AF?
- Breathlessness
- Palpitations
- Chest discomfort
- Syncope
- Stroke
How is the diagnosis of AF carried out?
- Manual pulse palpation for irregular pulse
- 12 lead ECG
- 24 hr ambulatory ECG if paroxysmal AF suspected
- Echocardiography
Give examples of other differential diagnosis
- Atrial flutter: saw tooth pattern of regular atrial activation
- Sinus tachy: >100bpm
- Supraventricular tachycardias
What is used to treat arrhythmias?
- Rate control
- Rhythm control
What is used in rate control?
- Beta blockers
- CCB (diltiazem or verapamil)
- Digoxin if v little exercise + options are ruled out
What is rhythm control and who is it for?
Cardioversion:
- New onset AF (<48hrs)
- Reversible cause (infection)
- HF caused/worsened by AF
- Atrial flutter for ablation
What is offered for new onset AF who will be treated by rhythm control?
- Pharmacological Cardioversion
- Anticoagulation
- Bleed risk
What is given for pharmacological cardioversion?
- Flecainide or amiodarone if not evidence of structural/ischaemic
HD - Amiodarone if evidence of structural HD
- > 48hrs/uncertain, delay cardioversion til maintained on anticoagulant for 3 wks. Offer rate control
When do you avoid beta blockers?
History of obstructive airway disease
Which beta blockers are used for lone AF?
Atenolol
- 50-100mg daily
- Monitor HR + BP
Which beta blocker is used for AF w/ Hx MI?
- Metoprolol
- Propranolol
- Atenolol
Which beta blocker is used for AF w/ Hx HF?
- Bisoprolol
- Carvedilol
- Nebivolol
What are the adverse effects of beta blockers?
- Bradycardia + hypotension
- Cold extremities
- Hypo/hyperglycemia in diabetes
- W/drawal effect
- Fatigue
Which CCBs are used in AF?
Diltiazem + verapamil
What are the interactions of CCBs?
- Simvastatin: cap at 20mg
- Avoid in HF: depress cardiac function + worsens symptoms (use amlodipine)
What are the side effects of CCBs?
- Headache
- Dizziness
- Hypotension
- Bradycardia
What is flecainide used for?
- Infrequent paroxysms + symptom induced by known precipitants
Paroxysmal AF:
- No Hx of LV dysfunction/valvular/IHD
- Hx infrequent symptomatic episodes
- SBP >100 + resting HR >70bpm
What is used to assess stroke risk?
CHA2DS2-VASc
what is used to assess bleeding risk + when is it used?
ORBIT
- Starting anticoagulant
- Reviewing anticoagulant
When do you offer/consider anticoagulation in AF?
- CHA2DS2-VASc of 2+
- Men w/ 1 score
What are used for anticoagulation in AF?
- Apixaban, dabigatran, edoxaban + rivaroxaban
- CI DOACs: vit K antagonist, if already on warfarin, switch treatment
Which patients are not offered anticoagulation?
<65 w/ AF + no risk factors other than gender
What happens if a patient is not taking anticoagulants?
- Review at 65
- Review if develops: diabetes, HF, atrial disease, coronary HD, stroke, ischaemic attack or thromboembolism
Which anticoagulation is used for new onset AF?
Heparin until anticoagulation started
In a confirmed AF diagnosis, onset <48hrs, when would you offer an oral anticoagulation?
- Stable sinus rhythm not restored w/in same 48hrs
- High risk of AF recurrence (failed cardioversion, structural HD + prolonged AF)
- Based on CHADSc-VASc
