1. Dr Avinash Haridas Pillai
Atrial Fibrillation
Dr Avinash Haridas Pillai

2. Background Most common sustained cardiac arrhythmia
Prevalence 0.5-1% in general population
It is characterised by an ECG:-
Lacking any consistent p waves
Irregular ventricular rate
Atrial arrhythmia where uniform activation is replaced by chaos such that coordinated contractile function is lost and the atria dilate
x10 fold greater in those over 65

3. Classification 1st detected vs.. Recurrent
Self terminating vs.. Not self terminating
Symptomatic vs... Asymptomatic
Paroxysmal (self terminating within 7 days)
Persistent (if cardioverted to SR by any means or last >7 days regardless of how it terminates)
Permanent (does not terminate or relapses within 24 hrs of cardioversion)
Lone (in the absence of structural heart disease) vs... Idiopathic (in the absence of any disease)
All episodes of AF lasting greater than 30s should be described as

4. Common Causes Hypertension Left Ventricular Failure
Coronary Artery Disease
Mitral/Tricuspid Valve Disease
HOCM
AF is common end point for many forms of cardiac disease where atrial myocytes are damaged to stress of ischaemia, cyanosis, intracavaty + pericardial pressures = altered conduction of the myocardium
Reversible – Alcohol/Hyperthyroid/MI/Pericarditis/Myocarditis/PE

5. Symptoms Palpitations Dyspnoea Fatigue Syncope Chest Pain
30% present with AF as incidental finding

6. Signs Irregular Pulse Variable intensity of 1st HS
Faster at apex than at wrist
Variable intensity of 1st HS
Absent “a” wave in the JVP

7. Investigations ECG CXR Bloods Echo 24 hr tape/ETT/Angiogram
FBC, UE, Cardiac Enzymes, TFT, LFT
Mg, Ca2+
Echo
24 hr tape/ETT/Angiogram

8. Management Make a diagnosis Decide on rate or rhythm control strategy
Stratify stroke risk and consider thromboprophylaxis

9. Rate vs. Rhythm control

10. Rate control Rate control first if:- Medication options:- over 65
with CHD (the vast majority)
Medication options:-
Beta-blocker or Calcium Antagonist (Verapamil/Diltiazem)
If still no better then add in Digoxin
Target heart rate of less than 90 bpm
Digoxin is not initial monotherapy
Rest – Beta blocker or Calcium Antagonist with Digoxin
Exercise – Calcium Antagonist with Digoxin

11. Rhythm control Refer for rhythm control (cardioversion) if:-
Symptomatic with congestive heart failure
Younger
Unable to achieve adequate
An antiarrhythmic drug is not required to maintain sinus rhythm for those patients in whom a precipitant (such as chest infection, fever etc.) has been corrected and cardioversion has been
performed successfully.

12. Bleeding risk with Warfarin
Over 75
NSAIDs
Past Hx of bleeding
Polypharmacy
Uncontrolled BP
On other antiplatelets

13. Stroke risk stratification

14. Stroke risk stratification and thromboprophylaxis
Low
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
Risk factors DM BP
Vascular disease (CAD + PVD)

15. Annual Risk of Stroke Risk 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%

16. CHADS2 Condition Points C Congestive Heart Failure 1 H
BP more than 160mmHg
Or Treated BP A
Age > 75 D
Diabetes S2
Prior stroke/TIA 2
Data from 65 – 95 year old patients with AF not on Warfarin

17. CHADS2 Score Annual Stroke Risk % Risk Therapy Range 1.9% Low Aspirin
1.9%
Low
Aspirin mg 1
2.8%
Moderate
Aspirin/Warfarin
2/>
4.0% >
High
Warfarin
INR 2-3

18. Paroxysmal AF Thromboprophylaxis Rhythm drugs Just the same
Standard B Blocker vs.. Pill in Pocket
Sotolol vs.. Class 1c agents
Amiodarone
Referral to EPS specialist
Consider a ’pill-in-the-pocket’ strategy for those who:
i) have no history of LV dysfunction, or valvular or ischaemic heart disease
ii) have a history of infrequent symptomatic episodes of paroxysmal AF
iii) have a systolic blood pressure > 100 mmHg and a resting heart rate above 70 bpm,
iv) are able to understand how and when to take the medication.

19. Atrial Flutter Same antithrombotic Rx as AF Re-establish SR
Cardiovert (Medication/DCCV)
Pacing

20. Papers
Mixed 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
Update of previous Cochrane review on anticoagulants (warfarin/ximelagatran) + antiplatelet (aspirin) therapy for non-rheumatic AF
19 trials including patients

21. Papers
Comparison of Warfarin vs. Aspirin- Clopidogrel in AF Lancet 2006:367:1903
Warfarin is superior to dual antiplatelet therapy
The study compared these 2 strategies in patients with AF and one other RF for stroke
Study was stopped early after a year
CVA rate was 3.93% with Warfarin and 5.6% for Clopidogrel + Aspirin
The bleeding rate with Aspirin + Clopidogrel was higher

22. Papers
BAFTA 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
973 patients aged over 75 recruited from primary care with AF, randomised to Aspirin 75mg or Warfarin (INR 2-3) and followed up for a mean of 2.7 years
Absolute annual event rates 1.8% Warfarin vs. 3.8%
aspirin i.e. ARR2%, NNT=50

23. Papers ACTIVE A Trial NEJM 2009;360:2066
Neither regime as effective as Warfarin
Warfarin %
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
Aspirin vs. Aspirin + Clopidogrel
Looking at alternative for patient with high risk of stroke but not suitable for Warfarin
7554 patients; RCT; Primary outcome was stroke, MI, embolism, vascular death
Major vascular event 7.6% vs. 6.8% (ARR 0.8%;NN 125)
Stroke occured in 3.3% vs. 2.4% (ARR 0.9%;NNT 111)
Major Bleeding increased from 1.3% to 2.0% (ARI 0.7% = NNH143)

24. Papers The 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%)
Dronedarone is a new antiarrythmic agent similar to amiodarone but shorter half life and reduced side effects.
RCT of 4600 high risk patients (over 70 + RF) and compared Dronedarone to placebo
Primary outcome was hospitalisation or death due to CV events
Critised for short f/u period 21 months + high drop out rate 30%

25. Papers
Aspirin + 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
Combination does not prevent more strokes but increases bleeding risk
These patients should just be on Warfarin

26. Questions

27. Summary Haemodynamically Stable Cause Rate vs. Rhythm Bleed risk
Stroke risk stratification
Thromboprophylaxis