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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 2010 - Heart Disease
NHS Board Residence (HB) Population with AFSubmitted Practices
PopulationPercentage (%)
Numerator Denominator
Ayrshire & Arran 1,512 112,292 1.3%
Dumfries & Galloway 483 29,581 1.6%
Fife 1,357 96,989 1.4%
Forth Valley 2,064 142,264 1.5%
Greater Glasgow & Clyde 9,625 673,305 1.4%
Highland 790 60,598 1.4%
Lanarkshire 1,700 129,339 1.3%
Lothian 1,354 98,918 1.3%
Orkney 69 4,189 1.4%
Shetland 138 9,849 1.6%
Tayside 237 12,617 1.4%
Western Isles 141 6,893 1.9%
SCOTLAND 19,470 1,376,834 1.4%
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
300-600bpm Ventricular rate depends
on degree of AV block 120-160bpm 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 75-300mg 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 75-300mg Warfarin to INR 2-3
See later
Stroke prevention (non-rheumatic AF)
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
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
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.
http://www.healthcareimprovementscotland.org/default.aspx?page=13900
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