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

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

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

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

NHS QIS Clinical Standards Audit 2010: AF PREVALENCE IN SCOTLAND NHS QIS Clinical Standards April Heart Disease NHS Board Residence (HB)Population with AF Submitted Practices Population Percentage (%) NumeratorDenominator Ayrshire & Arran1,512112,2921.3% Dumfries & Galloway48329,5811.6% Fife1,35796,9891.4% Forth Valley2,064142,2641.5% Greater Glasgow & Clyde9,625673,3051.4% Highland79060,5981.4% Lanarkshire1,700129,3391.3% Lothian1,35498,9181.3% Orkney694,1891.4% Shetland1389,8491.6% Tayside23712,6171.4% Western Isles1416,8931.9% SCOTLAND19,4701,376,8341.4%

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

Symptoms / Signs  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  bpm  Ventricular rate depends on degree of AV block  bpm  Peripheral rate slower (pulse deficit)

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

Normal Sinus Rhythm

‘Fast’ AF

‘Slow’ AF

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

Diagnosis  Based on:  ECG  Presentation  Response to treatment

Treatment objectives  Rhythm / rate control  Stroke prevention

Treatment strategies  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

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

 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

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

 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)

Paroxymal AF  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 mg  warfarin to INR 2-3  See later

Persistent AF  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

Permanent AF  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 mg  Warfarin to INR 2-3  See later

Stroke prevention (non-rheumatic AF)

Stroke Risk Assessment (CHADS 2 )  CChronic Heart Failure(1 point)  HHypertension (1 point)  AAge > 75 years (1 point)  DDiabetes (1 point)  SStroke, TIA or systemic embolisation (2 points)  Score < 2: low risk, aspirin* or anticoagulant  Score ≥ 2: high risk, anticoagulant indicated *Evidence for aspirin is weak

Stroke Risk Assessment (CHA 2 DS 2 VASc)  Alternative to CHADS 2  CChronic Heart Failure(1 point)  HHypertension (1 point)  AAge > 75 years (2 points)  DDiabetes (1 point)  SStroke, TIA or systemic embolisation (2 points)  Vvascular disease (1 point)  AAge years (1 point)  ScSex category (1 point if female)  Score ≥2 = High risk – anticoagulate unless contraindicated

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

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

Dabigatran Consensus NHS in Healthcare Improvement Scotland Working Group: National consensus 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. 

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