Atrial fibrillation Flashcards
Classification
Paroxysmal–>come on suddenly, revert spontaneously
Persistent–>abrupt onset, lasting days/weeks unless active measures to revert
Chronic–>inability to sustain sinu rhythm
Overview treatment
Rate control
Rhythm control
Anticoagulation
Initiation
Single circuit re-entry, ectopic acts as aberrant generators producing atrial tachyC
Maintenance, why is AFib more like to cause further AFib
The tachycardia causes atrial structural and electrophyisiological remodelling changes, further promoting AFib.
The longer they are in AFib the more difficult to revert
CHADS2 Risk of
Congestive heart failure Hypertension Age >75 (2) 65-74 (1) Diabetes Stroke/TIA (2) Female sex Vascular disease
CHADS score and stroke risk
0–>1.9% low risk Aspirin
1–>2.8% mod risk Oral anticoagulants
2-3–>4-6% mod risk Oral anticoagulant
4-6–>8-18% high risk Oral anticoagulant
ECG findings
No organised P waves Rapid atrial activity Fibrillatory baseline Irregularly irregular Wide QRS due to aberrancy
CVS examination findings
Palpitations Dizziness Dyspnea Irregularly irregular pulse Absent a wave on JVP No S4 on auscultation
To obtain and maintain long term ventricular rate
Atenolol or metoprolol
When can digoxin be used
Elderly sedentary patient
AFib + heart failure
Causes
CAD HTN HF Valvular disease Pericardial/Pleural disease Diabetes Thyroid Alcohol Fever PE
Investigations
ECG UEC-->potassium, magnesium Troponins TSH, T3, T4 CXR-->cardiomegaly, pneumonia (precipitant) TOE-->thrombus TTE-->CCF, valvular disease
Management in acute AF->when
02, IV access ECG trace Cardioversion-->electrical (100j in normal, 200J in larger) or chemical with amiodarone or flecainide (no CAF, normal LVF) Atenolol Enoxaparin for few days
When should cardioversion immediately be performed
Severe symptoms or compromised hemodynamically
When is it generally safe to cardiovert either electrically or chemically
Certain episode has been
What is the concern with using flecainide
May accelerate ventricular rate
Consider using which agents prior to cardioverting with flecainide
AV node blocker–>digoxin, beta blocker, verapamil
Management when unsure of time or >48 hours
02, ECG monitoring
TOE
If no thrombus->cardiovert
If thrombus, or TOE not done, fully anticoagulate for 3 weeks with enoxaparin 1mg/kg SC BD
Oral anticoagulation if required->warfarin
Atrial stunning
Unpredictable failure of atria to contract
When starting warfarin, what is the regime with heparin
Heparin concurrently for 5 days + until INR >2 on 2 consecutive days
Is long term therapy antiarrythmic required if AF due to transient condition
No
Maintenance of sinus after cardioversion
Flecainide or sotolol
What needs to be monitored with sotolol therapy
Excessive QT prolongation
Risk reduction of stroke with warfarin
70%
Risk of bleeding per annum
1-1.5%, up to 13% in 80yo +
Is the CHA2DS2Vasc for non-valvular or valvular
Non-valvular heart disease
What CHADSVasc score is indication for long term
> 2
Aspirin dose if indicated
100-300mg daily
Warfarin dose
Start at 5mg
