ECGs and Acute Cardiac Events Workshop

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

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

3. 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

4. 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

5. Impact on first line services • Timely assessment of chest pain in A&E • Extended skills of paramedics • Availability of Air Ambulances

7. ECG Lead Placement

9. 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

14. 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

17. 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

19. 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

20. 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

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

22. Choice of intervention • Drugs: • Not always reliable • Side effects • Every anti-arrhythmic is potentially pro-arrhythmic • Electricity: • Reliable • Patient considerations • Environmental considerations

23. 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

25. 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) Tachycardia Algorithm (with pulse) 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) Unstable Synchronised DC Shock* Up to 3 attempts • Amiodarone 300 mg IV over 10-20 min and repeat shock; followed by: • Amiodarone 900 mg over 24 h Stable Seek expert help Is QRS narrow (< 0.12 sec)? Narrow Broad Narrow QRS Is rhythm regular? Broad QRS Is QRS regular? Irregular Regular Irregular 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) • 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 Normal sinus rhythm restored? No Yes • Probable re-entry PSVT: • Record 12-lead ECG in sinus rhythm • If recurs, give adenosine again & consider choice of anti-arrhythmic prophylaxis • Possible atrial flutter • Control rate (e.g. -Blocker) *Attempted electrical cardioversion is always undertaken under sedation or general anaesthesia Seek expert help

26. 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

28. 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

29. 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

30. Example • 25 year old female • Presents to A&E • Palpitations • Sa02 97% on high flow oxygen • PR 200 BP 110/70

32. 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) Tachycardia Algorithm (with pulse) 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) Unstable Synchronised DC Shock* Up to 3 attempts • Amiodarone 300 mg IV over 10-20 min and repeat shock; followed by: • Amiodarone 900 mg over 24 h Stable Seek expert help Is QRS narrow (< 0.12 sec)? Narrow Broad Narrow QRS Is rhythm regular? Broad QRS Is QRS regular? Irregular Regular Irregular 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) • 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 Normal sinus rhythm restored? No Yes • Probable re-entry PSVT: • Record 12-lead ECG in sinus rhythm • If recurs, give adenosine again & consider choice of anti-arrhythmic prophylaxis • Possible atrial flutter • Control rate (e.g. -Blocker) *Attempted electrical cardioversion is always undertaken under sedation or general anaesthesia Seek expert help

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

34. Wolf Parkinson White

35. 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

36. 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

38. Adverse signs? • Systolic BP < 90 mmHg • Heart rate < 40 beats min-1 • Ventricular arrhythmias compromising BP • Heart failure Yes No Atropine 500 mcg IV Satisfactory Response? Yes No • Interim measures: • Atropine 500 mcg IV • repeat to maximum of 3 mg • Adrenaline 2-10 mcg min-1 • Alternative drugs • OR • Transcutaneous pacing • Risk of asystole? • Recent asystole • Möbitz II AV block • Complete heart block • with broad QRS • Ventricular pause > 3s Yes Observe Seek expert help Arrange transvenous pacing BRADYCARDIA ALGORITHM(includes rates inappropriately slow for haemodynamic state)

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

40. Example • 75 year old female • Presents to A&E • Palpitations • Sa02 95% on high flow oxygen • PR 175 irreg BP 80/50

42. 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 Atrial fibrillationTreatment based on risk to patient from the arrhythmia

43. Main learning points • Management of AF is complex • Universal agreement on high risk patients • Anticoagulation essential to prevent thromboembolic complications

44. Example • 35 year old male • Presents to A&E • Palpitations • Sa02 97% on high flow oxygen • PR 200 BP 110/70

46. Any Questions?

47. 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