ECGs and Acute Cardiac Events Workshop Dr. Stewart McMorran Consultant in Accident and Emergency MB,...

ECGs and Acute Cardiac Events Workshop

Dr. Stewart McMorran

Consultant in Accident and Emergency

MB, BCh, MRCS, FFAEM

Objectives

• Emergency management of common cardiac events

• ST elevation MIs

• Tachyarrhythmias

• Bradyarrhythmias

• Overview of management

• Interactive case discussions

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

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

Impact on first line services

• Timely assessment of chest pain in A&E

• Extended skills of paramedics

• Availability of Air Ambulances

ECG Lead Placement

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

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

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

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 22:334(8)

481-7

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

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

Arrhythmias - principles of treatment

• Choice of intervention

- drugs vs. electricity

• How symptomatic is patient

– How urgent is need for action

Choice of intervention

• Drugs:– Not always reliable

– Side effects

– Every anti-arrhythmic is potentially pro-arrhythmic

• Electricity:– Reliable

– Patient considerations

– Environmental considerations

How symptomatic is patient

• Signs of poor cardiac output– Heart rate

• Too fast – depends on rhythm

• Too slow – depends on patient

– Systolic blood pressure < 90 mm Hg– Chest pain– Breathlessness– Altered level of consciousness

TachycardiaAlgorithm (with pulse)

• Support ABCs: give oxygen; cannulate a vein• Monitor ECG, BP, SpO2

• Record 12-lead if possible, if not record rhythm strip• Identify and treat reversible causes (e.g. electrolyte abnormalities)

Seek expert help

Synchronised DC Shock*Up to 3 attempts

Seek expert help

Normal sinus rhythm restored?

Probable re-entry PSVT:• Record 12-lead ECG in sinus rhythm• If recurs, give adenosine again & consider choice of anti-arrhythmic prophylaxis

If Ventricular Tachycardia (or uncertain rhythm):• Amiodarone 300 mg IV over 20-60 min; then 900 mg over 24 h

If previously confirmed SVT with bundle branch block:• Give adenosine as for regular narrow complex tachycardia

• Amiodarone 300 mg IV over 10-20 min and repeat shock; followed by:• Amiodarone 900 mg over 24 h

Is patient stable?Signs of instability include:1. Reduced conscious level 2. Chest pain3. Systolic BP < 90 mmHg 4. Heart failure(Rate related symptoms uncommon at less than 150 beats min-1)

Is QRS narrow (< 0.12 sec)?Broad Narrow

Narrow QRSIs rhythm regular?

RegularIrregular

Broad QRSIs QRS regular?

• Use vagal manoeuvres• Adenosine 6 mg rapid IV bolus; if unsuccessful give 12 mg; if unsuccessful give further 12 mg.• Monitor ECG continuously

Irregular Narrow Complex Tachycardia Probable atrial fibrillationControl rate with:• -Blocker IV or digoxin IVIf onset < 48 h consider:• Amiodarone 300 mg IV 20-60 min; then 900 mg over 24 h

Irregular Regular

Possibilities include:• AF with bundle branch block treat as for narrow complex• Pre-excited AF consider amiodarone• Polymorphic VT (e.g. torsade de pointes - give magnesium 2 g over 10 min)

Yes No

Possible atrial flutter• Control rate (e.g. -Blocker)

*Attempted electrical cardioversion is always undertaken under sedation or general anaesthesia

Stable

Unstable

Example

• 65 year old male

• Presents to A&E

• Palpitations /chest pain

• MI 3 months ago

• Sa02 95% on high flow oxygen

• PR 190 BP 90/70

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

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

Example

• 25 year old female

• Presents to A&E

• Palpitations

• Sa02 97% on high flow oxygen

• PR 200 BP 110/70

TachycardiaAlgorithm (with pulse)

• Support ABCs: give oxygen; cannulate a vein• Monitor ECG, BP, SpO2

• Record 12-lead if possible, if not record rhythm strip• Identify and treat reversible causes (e.g. electrolyte abnormalities)

Seek expert help

Synchronised DC Shock*Up to 3 attempts

Seek expert help

Normal sinus rhythm restored?

Probable re-entry PSVT:• Record 12-lead ECG in sinus rhythm• If recurs, give adenosine again & consider choice of anti-arrhythmic prophylaxis

If Ventricular Tachycardia (or uncertain rhythm):• Amiodarone 300 mg IV over 20-60 min; then 900 mg over 24 h

If previously confirmed SVT with bundle branch block:• Give adenosine as for regular narrow complex tachycardia

• Amiodarone 300 mg IV over 10-20 min and repeat shock; followed by:• Amiodarone 900 mg over 24 h

Is patient stable?Signs of instability include:1. Reduced conscious level 2. Chest pain3. Systolic BP < 90 mmHg 4. Heart failure(Rate related symptoms uncommon at less than 150 beats min-1)

Is QRS narrow (< 0.12 sec)?Broad Narrow

Narrow QRSIs rhythm regular?

RegularIrregular

Broad QRSIs QRS regular?

• Use vagal manoeuvres• Adenosine 6 mg rapid IV bolus; if unsuccessful give 12 mg; if unsuccessful give further 12 mg.• Monitor ECG continuously

Irregular Narrow Complex Tachycardia Probable atrial fibrillationControl rate with:• -Blocker IV or digoxin IVIf onset < 48 h consider:• Amiodarone 300 mg IV 20-60 min; then 900 mg over 24 h

Irregular Regular

Possibilities include:• AF with bundle branch block treat as for narrow complex• Pre-excited AF consider amiodarone• Polymorphic VT (e.g. torsade de pointes - give magnesium 2 g over 10 min)

Yes No

Possible atrial flutter• Control rate (e.g. -Blocker)

*Attempted electrical cardioversion is always undertaken under sedation or general anaesthesia

Stable

Unstable

Main learning points

• Supraventricular tachycardias are often well tolerated

• Usually younger patients

• Vagal manoeuvres may be successful

• Adenosine is an effective anti-arrhythmic

Wolf Parkinson White

Wolf Parkinson White syndrome

• Uncommon cause of SVT• Presence of accessory pathway (bundle of

Kent)• Characteristic ECG features

– Short PR interval (<120 ms)– Wide QRS (>120 ms)– Delta wave (slurred upstroke)

• Unpredictable response to adenosine

Example

• 55 year old man

• Presents to A&E

• 1 hour history of central chest pain

• Sa02 97% on high flow oxygen

• PR 45 BP 80/50

BRADYCARDIA ALGORITHM(includes rates inappropriately slow for haemodynamic state)

Adverse signs?

• Systolic BP < 90 mmHg• Heart rate < 40 beats min-1

• Ventricular arrhythmias compromising BP• Heart failure

Atropine500 mcg IV

SatisfactoryResponse?

Risk of asystole?

• Recent asystole• Möbitz II AV block• Complete heart block with broad QRS• Ventricular pause > 3s

Interim measures:

• Atropine 500 mcg IV repeat to maximum of 3 mg• Adrenaline 2-10 mcg min-1

• Alternative drugs OR• Transcutaneous pacing

Seek expert helpArrange transvenous pacing

Yes No

Yes

Observe

YesNo

Main learning points

• Bradyarrhythmias may complicate inferior myocardial infarction (RCA supplies AVN)

• Atropine may be effective

• Pacing for symptomatic bradycardias resistant to atropine

Example

• 75 year old female

• Presents to A&E

• Palpitations

• Sa02 95% on high flow oxygen

• PR 175 irreg BP 80/50

Atrial fibrillation Treatment based on risk to patient from the arrhythmia

• High risk– Rate > 150 beats min-1

– Chest pain

– Critical perfusion

• Intermediate risk– Rate 100-150 beats min-1

– Breathlessness

– Poor perfusion

• Low risk– Rate < 100 beats min-1

– Mild or no symptoms– Good perfusion

Main learning points

• Management of AF is complex

• Universal agreement on high risk patients

• Anticoagulation essential to prevent thromboembolic complications

Example

• 35 year old male

• Presents to A&E

• Palpitations

• Sa02 97% on high flow oxygen

• PR 200 BP 110/70

Any Questions?

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