Atrial Fibrillation

Atrial Fibrillation • Cardiovascular ISCEE • 26th October 2010

How might AF present in GP? • People with an irregular pulse +/- • Breathlessness • Palpitations • Chest discomfort • Syncope/dizziness • Reduced exercise tolerance, malaise or polyuria • A potential complication of AF such as stroke, TIA or heart failure

Absence of an abnormal pulse makes a diagnosis of AF unlikely • But its presence does not reliably indicate AF. • Suspect paroxysmal AF if symptoms are episodic and last less than 48 hours.

What do we need to do with them? • ECG to confirm diagnosis • If paroxysmal AF suspected and 12-lead ECG is normal then arrange ambulatory electrocardiography • Bloods • CXR

TFTs – exclude hyperthyroidism • FBC – exclude anaemia • U&Es, Bone Profile, Glucose – exclude electrolyte disturbances which may precipitate AF • LFTs and clotting screen – assess suitability for warfarin • CXR – exclude lung abnormality such as lung cancer, also to detect heart failure

Which ones need to be referred? • Urgently • Patients with: • Pulse > 150 bpm and/or low BP (systolic less than 90 mmHg) • Loss of consciousness, severe dizziness, ongoing chest pain or increasing breathlessness • A complication of AF – stroke, TIA, acute HF

Which ones need to be referred? • Outpatients • New onset AF + • Young patient (age less than 50 yrs) • Suspected paroxysmal AF • Concurrent valve disease • LV systolic dysfunction on echo • Wolff-Parkinson-White syndrome or a prolonged QT interval is suspected on the ECG • Heart rate is difficult to control • Person continues to have symptoms despite rate control treatment

Rhythm vs Rate • Rhythm control preferred treatment for paroxysmal AF and in people with persistent AF with any of the following: • Symptomatic • < 65 yrs of age • First presentation with lone AF • AF secondary to a treated or corrected precipitant (eg infection) • Congestive heart failure • Rate controlled preferred treatment for permanent AF and in people with persistent AF and any of the following: • > 65 yrs age • Coronary artery disease • Contraindications to antiarrhythmic drugs • Unsuitable for cardioversion

GP Management • Rate control can be started in primary care • Beta-blockers, rate-limiting Ca-channel blockers, digoxin) • But rhythm control should only be done under specialist supervision • Amiodarone, fleicanide, sotalol • Start rate-control anyway if the person does not need admission but • Resting pulse >/= 90 bpm • Heart rate is fast on exertion, resulting in limited exercise tolerance

Initial Rate Control Treatment • Beta-blocker or rate limiting Ca-channel blocker (diltiazem or verapamil) unless this is contraindicated • Choice between the 2 groups depends on current medication and co-morbidities • Diltiazem preferred to verapamil because verapamil has a greater negative inotropic effect and interacts with digoxin • Digoxin suitable for older sedentary people in whom rate control is not needed during exercise

Subsequent Management • Review within 1 week – is the patient tolerating the drug? Review symptoms, heart rate, BP. • If drug not tolerated, prescribe an alternative. If symptoms not controlled, either increase dose or consider combination treatment. • To control symptoms during normal activities only, use beta-blocker/Ca-blocker with digoxin. • To control symptoms normal activities AND during exercise, use Ca-blocker with digoxin.

Subsequent Management • Do not use a beta-blocker and Ca-blocker to control AF in primary care • If symptoms are not controlled by beta-blocker plus digoxin OR Ca-blocker plus digoxin refer to cardiology

Antithrombotic Treatment • Everyone with AF (paroxysmal, persistent, permanent) should be offered antithrombotic treatment to reduce their risk of stroke • Offer either aspirin or warfarin without delay after confirming a diagnosis of AF • Choice should be based on person’s risk of stroke • Assess bleeding risk, likelihood of compliance with treatment and preferred options • Low risk of stroke – aspirin • Moderate risk of stroke – either aspirin or warfarin • High risk of stroke – warfarin

Assessing Bleeding Risk • Factors that increase risk of bleeding • Age > 75yrs • Use of antiplatelet drugs • Use of NSAIDs • Polypharmacy • Uncontrolled hypertension • Hx of bleeding (bleeding peptic ulcer, cerebral haemorrhage) • Hx of previous poorly controlled anticoagulation therapy

Assessing Stroke Risk • High risk • Previous ischaemic stroke / TIA or thromboembolic event • > 75yrs age with risk factors (hypertension, diabetes, coronary artery disease, peripheral artery disease) • Clinical evidence of valve disease or heart failure • Impaired LV function on echo • Moderate risk • > 65yrs age without risk factors • < 75yrs age with risk factors • Low risk • < 65yrs age without risk factors

CHADS2 • Congestive heart failure = 1 • Hypertension (or treated hypertension) = 1 • Age older than 75 years = 1 • Diabetes mellitus = 1 • previousStroke or TIA = 2 • Treat with aspirin if total score is 0 or 1 • Use warfarin if score is 2 or more

References • NICE 2006 ‘Atrial Fibrillation’ • Clinical Knowledge Summaries: ‘Atrial Fibrillation’

Atrial Fibrillation