ECGs%20and%20Acute%20Cardiac%20Events%20Workshop

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ECGs and Acute Cardiac Events Workshop

• Dr. Stewart McMorran
• Consultant in Accident and Emergency
• MB, BCh, MRCS, FFAEM

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Objectives

• Emergency management of common cardiac events
• ST elevation MIs
• Tachyarrhythmias
• Bradyarrhythmias
• Overview of management
• Interactive case discussions

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National Service Framework

• NSF for coronary artery disease established 2000
• Relevant to emergency medicine need for timely
  reperfusion therapy
• Door to needle time of 30 mins
• Call to needle time of 60 mins
• Results
• 75 eligible patients thrombolysed within 30
  minutes of hospital arrival

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Impact of NSF

• Emphasis on timely delivery of reperfusion
  therapy
• Thrombolysis most places
• Percutaneous Coronary Intervention
• Primary limited availability
• Rescue local policy if less than 50
  resolution in ST segment elevation after 90
  minutes
• Coronary artery bypass graft

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Impact on first line services

• Timely assessment of chest pain in AE
• Extended skills of paramedics
• Availability of Air Ambulances

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ECG Lead Placement
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Wall affected Leads Artery involved Reciprocal changes
Anterior V2-4 LAD II, III, aVF
Anterolateral I, aVL, V3-6 LAD, circumflex II, III, aVF
Anteroseptal V1-4 LAD
Inferior II, III, aVF RCA I, aVL
Lateral I, aVL, V5-6 circumflex II, III, aVF
Posterior V7-9 RCA V1-3
Right ventricular RV4-6 RCA
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Criteria for thrombolysis

• Chest pain, onset within last 12 hours plus any
  of
• ST elevation 2 mm or more in two contiguous chest
  leads
• ST elevation 1 mm or more in two contiguous limb
  leads
• Dominant R wave and ST depression in V1-3
• New LBBB

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Posterior MI

• Dominant R wave chest leads V1-3
• ST depression chest leads V1-3
• Turn ECG upside down and back to front see
  typical changes of STEMI
• Alternatively
• Posterior leads V7-9

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Left Bundle Branch Block and MI

• ST segment elevation more than 1 mm concordant
  (same direction) as QRS complex
• ST segment depression more than 1 mm in V1,2,3
• ST segment elevation more than 5 mm discordant
  (opposite direction) from QRS complex
• Sgarbossa E et al. NEJM 1996 Feb 22334(8) 481-7

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Pericarditis

• Widespread ST elevation (in leads looking at
  inflamed epicardium)
• Reciprocal depression in aVR and V1
• ST segment saddle shaped (concave upwards)
• No Q waves

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ST segment high take off

• Normal variant
• High take off or early repolarisation or J point
  elevation
• Younger patients
• Usually follows an S wave
• T wave maintains independent wave form
• No reciprocal ST segment depression
• If in doubt, compare with earlier ECGs

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Arrhythmias - principles of treatment

• Choice of intervention
• - drugs vs. electricity
• How symptomatic is patient
• How urgent is need for action

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Choice of intervention

• Drugs
• Not always reliable
• Side effects
• Every anti-arrhythmic is potentially
  pro-arrhythmic
• Electricity
• Reliable
• Patient considerations
• Environmental considerations

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How symptomatic is patient

• Signs of poor cardiac output
• Heart rate
• Too fast depends on rhythm
• Too slow depends on patient
• Systolic blood pressure lt 90 mm Hg
• Chest pain
• Breathlessness
• Altered level of consciousness

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Example

• 65 year old male
• Presents to AE
• Palpitations /chest pain
• MI 3 months ago
• Sa02 95 on high flow oxygen
• PR 190 BP 90/70

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How do you know it is VT ?

• May be difficult to distinguish ventricular
  tachycardia from atrial tachycardia with aberrant
  conduction e.g. LBBB
• Default position assume ventricular
• Look for confirmatory features
• capture beats
• fusion beats
• concordance
• extreme axis deviation

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Main learning points

• VT is a malignant arrhythmia
• DC cardioversion in presence of adverse signs
• Check electrolytes especially K and Mg2
• Amiodarone anti-arrhythmic of choice

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Example

• 25 year old female
• Presents to AE
• Palpitations
• Sa02 97 on high flow oxygen
• PR 200 BP 110/70

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Main learning points

• Supraventricular tachycardias are often well
  tolerated
• Usually younger patients
• Vagal manoeuvres may be successful
• Adenosine is an effective anti-arrhythmic

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Wolf Parkinson White
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Wolf Parkinson White syndrome

• Uncommon cause of SVT
• Presence of accessory pathway (bundle of Kent)
• Characteristic ECG features
• Short PR interval (lt120 ms)
• Wide QRS (gt120 ms)
• Delta wave (slurred upstroke)
• Unpredictable response to adenosine

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Example

• 55 year old man
• Presents to AE
• 1 hour history of central chest pain
• Sa02 97 on high flow oxygen
• PR 45 BP 80/50

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BRADYCARDIA ALGORITHM(includes rates
inappropriately slow for haemodynamic state)
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Main learning points

• Bradyarrhythmias may complicate inferior
  myocardial infarction (RCA supplies AVN)
• Atropine may be effective
• Pacing for symptomatic bradycardias resistant to
  atropine

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Example

• 75 year old female
• Presents to AE
• Palpitations
• Sa02 95 on high flow oxygen
• PR 175 irreg BP 80/50

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Atrial fibrillation Treatment based on risk to
patient from the arrhythmia

• High risk
• Rate gt 150 beats min-1
• Chest pain
• Critical perfusion
• Intermediate risk
• Rate 100-150 beats min-1
• Breathlessness
• Poor perfusion

• Low risk
• Rate lt 100 beats min-1
• Mild or no symptoms
• Good perfusion

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Main learning points

• Management of AF is complex
• Universal agreement on high risk patients
• Anticoagulation essential to prevent
  thromboembolic complications

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Example

• 35 year old male
• Presents to AE
• Palpitations
• Sa02 97 on high flow oxygen
• PR 200 BP 110/70

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Any Questions?
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Summary

• Chest pain is a common cause of attendance to
  hospital
• Important to recognise STEMI
• Arrhythmias may precede or complicate MI
• Standardised treatment algorithms for initial
  management