Atrial fibrillation Flashcards
Atrial fibrillation definition
A chaotic irregular atrial rhythm at 300-500bpm the AV node responds intermittently hence an rregular ventriculr rate
Causes of AF
- heart failure
- MI
- hyperthyrodism
- caffiene
- alcohol
Symptoms
- asymptomatic
- chest pain
- palpitations
- dypsnoea
- Dizziness/syncope
Signs
- irregularly irregular pulse
- apical pulse is greater than the radial rate
- 1st heart sound is of varying intensity
- signs of LV dysfunction
Tests
- Thorough history - onset, duration, associated symptoms
- Cardovascular exam- irregularly, irregular pulse
- 24 hour ECG tape- useful for paroxysmal AF
- ECG - absent Pwaes, irregular QRS complex
- Blood tests: Uand e (renal dysfunction), cardiac enzymes, thyroid function tests
- echo - for mitral valve disease, left ventricular dysfunction
Three forms of AF
- paroxysmal atrial fibrillation
- Persisten Atrial fibrillation
- Permanent atrial fibrillation
Paroxysmal AF
atrial fibrillation terminates spontaneously and usually lasts less than 48 hours, but may recur.
Paroxysmal Atrial fibrillation treatment
- Rhythm control is the preferred management¹
- First appropriate thrombo-prophylaxis should be administered – based on stroke risk
- 1st line
- Flecainide (Pill in the pocket approach) only if patient has all of the following:¹
- No LV dysfunction, valvular, or ischaemic heart disease
- A history of infrequent symptomatic episodes of paroxysmal AF
- A systolic blood pressure of >100mmHg & a resting heart rate >70bpm
- An understanding of how & when to take the medication
- If pill in the pocket approach not suitable try a standard beta blocker i.e. Atenolol
- 2nd Line
- Depends of the presence or absence of Coronary artery disease (CAD) or LV dysfunction (LVD)
- CAD / LVD present – Sotalol
- CAD / LVD absent – Classic 1c agent or Sotalol (can be titrated from 80mg BD up to 240mg BD)¹
- Depends of the presence or absence of Coronary artery disease (CAD) or LV dysfunction (LVD)
- 3rd Line
- If the above fails:
- Amiodarone can be tried
- Referral to a cardiologist for further specialist investigation should be considered
Persistent AF
remain in atrial fibrillation but sinus rhythm can be restored e.g. by cardioversion either electrically or with drugs
Persistent AF treatment
Rate Vs Rhythm control
Rhythm is recommended 1st line in patients with persistent AF:
- symptomatic
- younger
- presenting for the first time with lone AF
- Whos AF is secondary to a treated or corrected precipitant
- CHF
Rate is recommended 1st line in patients with persistent AF if:
- over 65
- with CAD
- with contraindications to anti-arrhythmic drugs
- unsuitable for cardoversion
Rhythm control for persistent AF
- **Atrial Fibrilliation onset is
- give heparin
- perform electrical or chemical cardioverson (amiodarone if structural heart disease, flecainide if not)
- no long term anticoagulation necessary**
-
Atrial fibrillation onset longer than 48 hours ago
- give 3 weeks therapeutic anticoagulation prior to cardioversion
- or perform TOE guided cardioversion
- If patient is at high risk of cardioversion failure (e.g. previous AF recurrence) – give 4 weeks Sotalol prior to procedure
- Perform electrical cardioversion
- Give 4 weeks anticoagulation post-procedure
- If patient is deemed high risk for stroke then long term anticoagulation should be commenced – Warfarin – INR 2-3
Permanent AF
which is chronic and it is accepted that sinus rhythm can not be restored or may be inappropriate.
Permanent AF treatment
- Thrombopropylaxis - based on stroke risk (CHA2DS2VASc)
- Rate control is needed if:
- Resting heart rate >90bpm (110bpm for those with recent onset AF)
- Exercise heart rate is >200bpm minus patient age
- 1st line - BB or Rate limiting calcium antagoinst
- 2nd line-
- if resting HR remains >90bpm - beta blocker or rate limiitng calcium anatagonist _ DIgoxin
- If exercise heart rate is the problem - Rate limiting calcium anatgonist + Digoxin
- 3rd line - if all above treaments still fail then
- refer patient to cardiologist
- refer patient to cardiologist
Acute AF management
<48 hours duration, patients will usually be younger and are more likely to have an identifiable cause
- ABC
- immediate cardioversion - do not delay treatment to give anticoagulants (ITU with sedation, 200J shock initialy, if unseccessful two further attmepts at 360J)
- Treat underlying cause (MI, Pneumonia)
-
Control ventricular rate
- 1st line -verampili, bisoprosol
- 2nd line- digoxin or amiodarone
-
Initiate anticoagulation - with heparin to prevent thrombus formation
- thrombi contraindicated - do trans-oesphageal ultrasoun before cardioversion
- Consider Drug cardioversion
48hr cardioversion time limit however, if Trans-oesophageal ultrasound clean then okay to cardiovert after 48hrs
Chronic AF
Main goal is rate control and anti-coagulation
Rate control
- Rate control is as good as rhythm control in chronic AF – i.e. generally you don’t need to cardiovert – as the outcomes are the same as if the rate only is well controlled.Exceptions include:
- Young patients,
- 1st episode of AF
- 1st line – β-blocker OR Ca2+ blocker
- using both together is contraindicated as it can cause heart block
- 2nd line – same as above, but add digoxin, or amiodarone.
Digoxin as the sole treatment for AF is not widely acceptable – may be suitable for some very sedentary elderly patients.
Don’t give β-blockers with verapamil or diltiazem (L- type calcium channel blockers) as there is a risk of bradycardia
Rhythm control
- cardioversion chosen do echo 1st
- pre-treat for 4 weeks with amiodarone if increased risk of cardio failure
- pharmacological cardioversion
- 1st line- Flecainide if no structure heart disease (IV amiodarone if there is)
- Av node alblation
How to asses the risk of stroke and thus the degree of anticoagulation therapy
Score <2 - low risk - no specific anticoagulation
Score >2- HIgh risk - warfarin (targer INR 2-3)
- Dont use warfarin if contraindicated
- wary of warfarin to patients at high risk of fall (typically, very old patient with many co-morbidites)
- warfarin reduces stroke risk by 70% - Risk in AF patients is 4%/ year. with warfarin this is about 1%/year
