Atrial FibrillationAtrial FibrillationDr Avinash Haridas Pillai

BackgroundBackgroundMost common sustained cardiac

arrhythmiaPrevalence 0.5-1% in general

populationIt is characterised by an ECG:-

◦Lacking any consistent p waves◦Irregular ventricular rate

ClassificationClassification1. 1st detected vs.. Recurrent2. Self terminating vs.. Not self terminating3. Symptomatic vs... Asymptomatic4. Paroxysmal (self terminating within 7

days)5. Persistent (if cardioverted to SR by any

means or last >7 days regardless of how it terminates)

6. Permanent (does not terminate or relapses within 24 hrs of cardioversion)

7. Lone (in the absence of structural heart disease) vs... Idiopathic (in the absence of any disease)

Common CausesCommon CausesHypertensionLeft Ventricular FailureCoronary Artery DiseaseMitral/Tricuspid Valve DiseaseHOCM

SymptomsSymptomsPalpitationsDyspnoeaFatigueSyncopeChest Pain30% present with AF as

incidental finding

SignsSignsIrregular Pulse

◦Faster at apex than at wristVariable intensity of 1st HSAbsent “a” wave in the JVP

InvestigationsInvestigationsECGCXRBloods

◦FBC, UE, Cardiac Enzymes, TFT, LFT◦Mg, Ca2+

Echo24 hr tape/ETT/Angiogram

ManagementManagementMake a diagnosisDecide on rate or rhythm control

strategyStratify stroke risk and consider

thromboprophylaxis

Rate vs. Rhythm controlRate vs. Rhythm control

Rate controlRate controlRate control first if:-

◦over 65 ◦with CHD (the vast majority)

Medication options:-◦Beta-blocker or Calcium Antagonist

(Verapamil/Diltiazem)◦If still no better then add in Digoxin

Rhythm controlRhythm controlRefer for rhythm control

(cardioversion) if:-◦Symptomatic with congestive heart

failure◦Younger◦Unable to achieve adequate

Bleeding risk with Bleeding risk with WarfarinWarfarinOver 75NSAIDsPast Hx of bleedingPolypharmacyUncontrolled BPOn other antiplatelets

Stroke risk stratificationStroke risk stratification

Stroke risk stratification and Stroke risk stratification and thromboprophylaxisthromboprophylaxisLow

◦ Under 65 and no risk factor◦ Aspirin if no contraindications

Moderate◦ Over 65 and no risk factors◦ Under 75 with risk factors◦ Aspirin vs. Warfarin

High◦ Previous ischaemic event/TIA◦ Over 75 with risk factors; valve disease or

heart failure◦ Warfarin if no contraindications

Annual Risk of StrokeAnnual Risk of StrokeRisk Group No Rx Aspirin Warfarin

Very High (prev CVA/TIA)

12% 10% 5%

High 5-8% 4-6% 2-3%

Moderate 3-5% 2-4% 1-2%

Low 1.2% 1% 0.5%

CHADSCHADS22

Condition Points

C Congestive Heart Failure 1

H BP more than 160mmHgOr Treated BP

1

A Age > 75 1

D Diabetes 1

S2 Prior stroke/TIA 2

CHADSCHADS22

Score

Annual Stroke Risk %

Risk Therapy Range

0 1.9% Low Aspirin 75- 300 mg

1 2.8% Moderate Aspirin/Warfarin

2/> 4.0% > High Warfarin INR 2-3

Paroxysmal AFParoxysmal AFThromboprophylaxis

◦Just the sameRhythm drugs

◦Standard B Blocker vs.. Pill in Pocket◦Sotolol vs.. Class 1c agents◦Amiodarone◦Referral to EPS specialist

Atrial FlutterAtrial FlutterSame antithrombotic Rx as AFRe-establish SR

◦Cardiovert (Medication/DCCV)◦Pacing

PapersPapersMixed comparison of stroke

prevention treatments in patients with non-rheumatic AF – Arch Int Med 2006:166:1269◦Warfarin more effective than Aspirin

in reducing stroke in AF◦Warfarin: will prevent 28 strokes at

the cost of 11 major bleeds◦Aspirin: will prevent 16 strokes at the

cost of 6 major bleeds

PapersPapersComparison of Warfarin vs.

Aspirin-Clopidogrel in AF Lancet 2006:367:1903◦Warfarin is superior to dual

antiplatelet therapy

PapersPapersBAFTA study 2007: Warfarin vs.

Aspirin in an elderly, community population. Lancet 2007:370:493◦Support the use of Warfarin over

Aspirin in patients over 75 unless there are contraindications

PapersPapersACTIVE A Trial NEJM 2009;360:2066

◦Neither regime as effective as Warfarin Warfarin 1.1-1.3% Aspirin 3.3% Aspirin + Clopidogrel 2.4%

◦Conclusion: In patients with moderate to high risk of stroke in whom Warfarin is unsuitable, the combination of Clopidogrel + Aspirin will be most likely to provide NET clinical benefit

PapersPapersThe ATHENA Study. NEJM

2009:360:668◦Primary outcome occured in 32% of

the Dranadone group vs. 39% of the placebo (ARR of 7% = NNT 14)

◦Significant reduction in CV deaths (2.7% vs. 3.9%)

PapersPapersAspirin + Warfarin in patients

with AF and vascular disease BMJ2008:336:614◦If a patient taking Aspirin for a CVA

develops AF stop Aspirin start Warfarin

QuestionsQuestions

SummarySummaryHaemodynamically StableCauseRate vs. RhythmBleed riskStroke risk stratification Thromboprophylaxis