Atrial Fibrillation – a simple pulse check to prevent a stroke?

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Atrial Fibrillation a simple pulse check to
prevent a stroke?

• Dr Kneale Metcalf

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Overview

• Atrial fibrillation
• Stroke and atrial fibrillation
• Detecting atrial fibrillation
• Managing atrial fibrillation

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What is atrial fibrillation (AF)?
Atrial fibrillation is an atrial tachyarrhythmia
characterised by predominantly uncoordinated
atrial activation
A fast / irregular heart
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What happens in the heart?
Sinus rhythm
AF
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ECG
Most commonly diagnosed by an ECG
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Classification of AF
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The Incidence of AF is Increasing in the United
Kingdom

• In 1995, 0.9 of the United Kingdom population
  were affected by AF2
• By 2006 this figure had risen to 1.31
• The prevalence of AF will continue to rise as the
  proportion of elderly patients increases
• By 2050, it is estimated that AF will be present
  in 2 of the general population, and in a far
  higher proportion of elderly patients2

• NICE Clinical Guideline 36 costing report.
  Available at http//www.nice.org.uk/nicemedia/pdf
  /CG036costingreport.pdf. Accessed January 14,
  2010
• Stewart S, et al. Heart 2004 90 28692 3.
  Savelieva I, et al. Europace 2008 10 64765

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Other points about AF

• Can be symptomatic or asymptomatic
• If asymptomatic then how do you pick it up?

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Core message

• Atrial fibrillation is common and getting
• commoner

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AF and stroke
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One sixth of all strokes are attributable to AF

Wolf et al. Stroke 1991 22 983-988
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AF is an Independent Risk Factor for Stroke

• AF patients have nearly a fivefold increased risk
  of stroke compared with patients without AF1

plt0.001 for all age groups
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4.5
4.0
4
3.3
Relative risk of stroke compared to patients
without AF
2.6
3
2
1
0
5059
6069
7079
8089
Age (years)
1. Wolf PA, et al. Stroke 1991 22 9838
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The Impact of AF on Stroke Outcomes

• Survival is poorer and stroke recurrence rates
  are higher following AF-related stroke

Framingham (10-year follow up from 1981)
AFatrial fibrillation ORodds ratio
CIconfidence interval 1. Lin HJ, et al. Stroke
1996 27 17604 2. Dulli DA, et al.
Neuroepidemiology 2003 22 11823
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The Impact of AF on Stroke Outcomes

• Functional outcomes of stroke are significantly
  worse in patients with AF, and more patients
  remain bedridden

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OR for bedridden state following stroke due to AF
was 2.23 (95 CI 1.87, 2.59)
41.2
40
plt0.0005
Patients bedridden on admission ()
30
23.7
20
10
0
Without AF(n867)
With AF(n194)
AFatrial fibrillation ORodds ratio
CIconfidence interval Dulli DA, et al.
Neuroepidemiology 2003 22 11823
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Core message

• Atrial fibrillation
• causes stroke

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Detecting AF
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Detecting AF

• Pulse
• ECG
• 24hr ECG
• Fancy kit

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AF how can it be diagnosed?

• ECG (preferably 12-lead)
• Still the cornerstone of AF diagnosis

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Opportunistic screening

• Taken up by 2 PBC Consortia this year in Norfolk
  during flu vaccination
• IDEAL setting
• High risk patients
• Nurse vaccination
• Done to protocol
• GP paid!
• Evidence of effectivness
• N Essex screened 30000 in 6 weeks
• 361 patients newly diagnosed with AF

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Protocol

• Patients aged over 65 years, who have no record
  of AF, will have
• their pulse checked for at least 30 seconds to
  look for irregularity.
• If irregularity is identified, then they will be
  followed up with
• resting 12-lead ECG
• blood tests for lipid profile, renal function,
  fasting glucose, full blood count, thyroid
  function
• body mass index
• urinalysis
• clinical assessment of cardiovascular system
• overall evaluation of cardiovascular risk
• Management options will include
• warfarin (or antiplatelet agents if warfarin
  contraindicated)
• pulse rate control
• consideration of referral for cardioversion.

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24 hr ECG (and longer)

• As AF can be paroxysmal then one off pulse or ECG
  may miss!
• 24 hr ECG may have a better pick up

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Effectiveness of different rhythm detectors
Jabaudon D, Sztajzel J, Sievert K et al.
Usefulness of ambulatory 7-day ECG monitoring for
the detection of atrial fibrillation and flutter
after acute stroke and transient ischemic attack.
Stroke. 200435(7)16471651.
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CARDIST Trial

• Patients with stroke or TIA
• No Hx AF
• 24 hr ECG, 7 day automated device, wrist watch
  device
• Comparing AF pick up rate

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Core message

• AF can be detected
• by a simple pulse
• check

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Managing AF

• Blood thinning
• Antiplatelets
• Anticoagulation
• Rhythm control
• Rate
• Stabalisation
• Operations

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The CHADS2 Scoring System

• CHADS2 is a points-based system for predicting
  risk of stroke in AF based on key risk factors1
• Congestive heart failure 1 point
• Hypertension 1 point
• Age gt75 years 1 point
• Diabetes mellitus 1 point
• Stroke or TIA 2 points

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Aspirin
Stroke reduction of 19 (95 CI 2 to 34)
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Warfarin
Risk reduction of 62 (95 CI 48 to 72) versus
placebo
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RE-LY Trial (Dabigatran)

• Dabigatran
• Direct thrombin inhibitor
• NON MONITORED ANTICOAGULATION
• 18000 patients, compared to warfarin
• 150mg better than warfarin (RRR 34)

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Rate / rhythm control

• Beta blockers
• Amiodarone
• Flecainide
• Digoxin
• Etc.
• New antiarrhythmic agent Dronederone
• Cleaner amiodarone
• Trial ATHENA
• 4628 patients (PAF)
• 24 RRR of hospitalisation or death from any
  cause

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Operations

• RF ablations

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Core message

• Treatment is effective

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Summary

• A simple pulse check can prevent a stroke!