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 Anteroseptal V1-4 Inferior RCA I, aVL Lateral I, aVL, V5-6 circumflex Posterior V7-9 V1-3 Right ventricular RV4-6

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 check

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 J point = junctional point = where ST segment takes off from QRS complex

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

Synchronised DC Shock* Is QRS narrow (< 0.12 sec)? Tachycardia Algorithm (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 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 pain 3. 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 QRS Is rhythm regular? Regular Irregular Broad QRS Is 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 fibrillation Control rate with: -Blocker IV or digoxin IV If onset < 48 h consider: Amiodarone 300 mg IV 20-60 min; then 900 mg over 24 h 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

Synchronised DC Shock* Is QRS narrow (< 0.12 sec)? Tachycardia Algorithm (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 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 pain 3. 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 QRS Is rhythm regular? Regular Irregular Broad QRS Is 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 fibrillation Control rate with: -Blocker IV or digoxin IV If onset < 48 h consider: Amiodarone 300 mg IV 20-60 min; then 900 mg over 24 h 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

Arrange transvenous pacing 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 Atropine 500 mcg IV Satisfactory Response? 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 help Arrange transvenous pacing Yes No Observe

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