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