Atrial Fibrillation

1. Atrial Fibrillation Steve McGlynn Specialist Principal Pharmacist (Cardiology), Greater Glasgow and Clyde Honorary Clinical Lecture, University of Strathclyde

3. Some types of arrhythmia • Supraventricular • Sinus Nodal • Sinus bradycardia • Sinus tachycardia • Sinus arrhythmia • Atrial • Atrial tachycardia • Atrial flutter • Atrial fibrillation • AV Nodal • AVNSVT • Heart blocks • Junctional • Ventricular • Escape rhythms • Ventricular tachycardia • Ventricular fibrillation

4. Atrial fibrillation • A heart rhythm disorder (arrhythmia). It usually involves a rapid heart rate, in which the upper heart chambers (atria) are stimulated to contract in a very disorganized and abnormal manner. • A type of supraventricular tachyarrhythmia • The most common arrhythmia

6. Rheumatic heart disease Coronary heart disease (MI) Hypertension Myopericarditis Hypertrophic cardiomyopathy Cardiac surgery Thyrotoxicosis Infection Alcohol abuse Pulmonary embolism Caffeine Exercise Lone AF Aetiology

7. NHS QIS Clinical Standards Audit 2010: AF PREVALENCE IN SCOTLAND

9. New / Recent onset < 48 hours Paroxysmal variable duration self terminating Persistent Non-self terminating Cardiovertable Permanent Non-self terminating Non-cardiovertable Classification

10. Breathlessness / dyspnoea Palpitations Syncope / dizziness Chest discomfort Stroke / TIA 6 x risk of CVA 2 x risk of death 18 x risk of CVA if rheumatic heart disease Irregularly irregular pulse Atrial rate 300-600bpm Ventricular rate depends on degree of AV block 120-160bpm Peripheral rate slower (pulse deficit) Symptoms / Signs

11. Investigations • Electrocardiogram (ECG) • All patients • May need ambulatory monitoring • Transthoracic echocardiogram (TTE) • Establish baseline • Identify structural heart disease • Risk stratification for anti-thrombotic therapy • Transoesophogeal echocardiography (TOE) • Further valve assessment • If TTE inconclusive / difficult

12. Normal Sinus Rhythm

13. ‘Fast’ AF

14. ‘Slow’ AF

15. Investigations • Electrocardiogram (ECG) • All patients • May need ambulatory monitoring • Transthoracic echocardiogram (TTE) • Baseline • Structural heart disease • Risk stratification for anti-thrombotic therapy • Transoesophogeal echocardiography (TOE) • Further valve assessment • TTE inconclusive / difficult

16. Diagnosis • Based on: • ECG • Presentation • Response to treatment

17. Treatment objectives • Rhythm / rate control • Stroke prevention

18. New / Recent onset Cardioversion Rhythm control Paroxysmal Rate control or cardioversion during paroxysm Rhythm control if needed Persistent Cardioversion Rhythm control Peri-cardioversion thromboprophylaxis Permanent Rate control Thromboprophylaxis Treatment strategies

19. Pharmacological Options • Class Ic Anti-arrhythmics • Flecainide / Propafenone • Rhythm control • May also be pro-arrhythmic • Class II Anti-arrhythmics • Beta-blockers • Mainly rate control • Control rate during exercise and at rest • Generally first choice • Choice depends on co-morbidities

20. Class III Anti-arryhthmics • Amiodarone / Dronedarone • Mainly rhythm control • May be pro-arrhythmic • Concerns over toxicity • Class IV Anti-arryhthmics • Calcium channel blockers (verapamil / diltiazem only) • Rate control only • Alternative to beta-blockers if no heart failure • Digoxin • Rate control only • Does not control rate during exercise • Third choice unless others contra-indicated

21. Acute AF Treatment will depend on: • History of AF • Time to presentation (<> 24 hours) • Co-morbidities (CHD, CHF/LVSD etc) • Likelihood of success (History)

22. Rate Vs. Rhythm control • Rhythm control not feasible or safe • Beta-blocker • Verapamil • Digoxin (CHF) • Rhythm control if possible and safe • DC cardioversion (if possible) • Amiodarone (CHD or CHF/LVSD) • Flecainide (Paroxysmal AF)

23. Rhythm control* Beta-blocker Class 1c agent or sotalol If CHD - sotalol If LVD: Amiodarone Dronedarone? Not if heart failure *May be “Pill in the pocket” Antithrombotic therapy as per risk assessment Aspirin 75-300mg warfarin to INR 2-3 See later Paroxymal AF

24. Rhythm control Beta blocker No structural heart disease: Class 1c* or sotalol Structural heart disease: amiodarone Rate control As for permanent AF * not if CHD present Antithrombotic therapy as per risk assessment Pre-cardioversion thromboprophylaxis of at least 3 weeks If rate control, as for permanent AF Persistent AF

25. Beta blocker or Calcium channel blocker and/or Digoxin Amiodarone? Option if poor rate control on above Dronedarone? Increased mortality Antithrombotic therapy as per risk assessment Aspirin 75-300mg Warfarin to INR 2-3 See later Permanent AF

26. Stroke prevention (non-rheumatic AF)

27. Stroke Risk Assessment (CHADS2) • C Chronic Heart Failure (1 point) • H Hypertension (1 point) • A Age > 75 years (1 point) • D Diabetes (1 point) • S Stroke, TIA or systemic embolisation (2 points) • Score < 2: low risk, aspirin* or anticoagulant • Score ≥ 2: high risk, anticoagulant indicated *Evidence for aspirin is weak

28. Stroke Risk Assessment (CHA2DS2VASc) • Alternative to CHADS2 • C Chronic Heart Failure (1 point) • H Hypertension (1 point) • A Age > 75 years (2 points) • D Diabetes (1 point) • S Stroke, TIA or systemic embolisation (2 points) • V vascular disease (1 point) • A Age 65-74 years (1 point) • Sc Sex category (1 point if female) • Score ≥2 = High risk – anticoagulate unless contraindicated

29. Bleeding Risk Assessment(HAS-BLED) • 1 point each for: • Hypertension • Abnormal renal/liver function (1 for each) • Stroke • Bleeding history or predisposition • Labile INR • Elderly (age over 65) • Drugs*/alcohol** concomitantly (1 for each) *Drugs that increase bleeding, e.g. aspirin ** Alcohol excess

30. Anticoagulants • Warfarin remains standard anticoagulant at present • 3 new oral anticoagulants • Dabigatran (Direct thrombin inhibitor) • Licensed by MHRA • Approved by SMC • Rivaroxiban (Factor Xa inhibitor) • Licensed by MHRA • Apixaban (Factor Xa inhibitor) • Fixed doses • No monitoring • At least as effective as warfarin • Safer than warfarin? • Dabigatran capsules not stable outside of original blister • Very difficult to reverse effect unlike warfarin • Much more expensive (even allowing for INR costs) • Place in therapy not clear yet

31. Dabigatran Consensus NHS in Healthcare Improvement Scotland Working Group: Nationalconsensus on dabigatran The consensus statement states that: • on balance of risks and benefits, warfarin remains the anticoagulant of clinical choice for moderate or high risk atrial fibrillation patients (CHA2DS2-VASc ≥ 2) with good INR control, and • clinicians should consider prescribing dabigatran in patients with: • poor INR control (less than 60% of time in INR range) despite evidence that they are complying, or • allergy to or intolerable side effects from coumarin anticoagulants. • http://www.healthcareimprovementscotland.org/default.aspx?page=13900

32. Conclusions • AF is a common condition. • Patients may be unaware of its presence and are therefore at risk of a stroke • Effective treatment strategies exist to control symptoms • Effective treatment strategies exist to reduce the risk of stroke • Patient education and choice are central to improving the likelihood of treatment success