1. 12 Lead ECGs: Ischemia, Injury & Infarction Terry White, RN, EMT-P

2. Ischemia, Injury & Infarction H Definitions H Injury/Infarct Recognition H Localization & Evolution H Reciprocal Changes H The High Acuity Patient

3. The Three I’s H Ischemia Flack of oxygenation FST segment depression or T wave inversion H Injury Fprolonged ischemia FST segment elevation H Infarct Fdeath of tissue Fmay or may not show a Q wave

4. Injury/Infarct Recognition Epicardial Coronary Artery Lateral Wall of LV Positive Electrode Septum Interior Wall of LV Well Perfused Myocardium

5. Injury/Infarct Recognition Normal ECG

6. Injury/Infarct Recognition Epicardial Coronary Artery Lateral Wall of LV Septum Interior Wall of LV Ischemia Positive Electrode Left Ventricular Cavity

7. Injury/Infarct Recognition H Ischemia FInadequate oxygen to tissue FRepresented by ST depression or T inversion FMay or may not result in infarct or Q waves

8. Injury/Infarct Recognition ST Segment Depression

9. Injury/Infarct Recognition Thrombus Ischemia Injury

10. Injury/Infarct Recognition H Injury FProlonged ischemia FRepresented by ST elevation W referred to as an “injury pattern” FUsually results in infarct W may or may not develop Q wave

11. Injury/Infarct Recognition ST Segment Elevation

12. Injury/Infarct Recognition Infarcted Area Electrically Silent Depolarization Infarct

13. Injury/Infarct Recognition H Infarct FDeath of tissue FRepresented by Q wave FNot all infarcts develop Q waves

14. Injury/Infarct Recognition Q Waves

15. Injury/Infarct Recognition Infarcted Area Electrically Silent Thrombus Depolarization Ischemia

16. Injury/Infarct Recognition H What to Look for: FST segment elevation FPresent in two or more anatomically contiguous leads

17. Injury/Infarct Recognition: Practice

18. Localization Inferior: II, III, AVF Septal: V1, V2 Anterior: V3, V4 Lateral: I, AVL, V5, V6 I II III aVR aVL aVF V1 V2 V3 V4 V5 V6

19. Localization I Lateral II Inferior III Inferior aVR aVL Lateral V1 Septal aVF Inferior V2 Septal V3 Anterior V4 Anterior V5 Lateral V6 Lateral Which coronary arteries are most likely associated with each group of contiguous leads?

20. Localization: Left Coronary Artery Left Main Left Circumflex Lateral Wall Anterior Wall of Left Ventricle Septal Wall Right Ventricle Right Coronary Artery Anterior Descending Artery

21. Localization: Left Coronary Artery (LCA) H Left Main (proximal LCA) occlusion FExtensive Anterior injury H Left Circumflex (LCX) occlusion FLateral injury H Left Anterior Descending (LAD) occlusion FAnteroseptal injury

22. Localization Practice ECG

25. Localization: Extensive Anterior MI H Evidence in septal, anterior, and lateral leads H Often from proximal LCA lesion H “Widow Maker” H Complications common FLeft ventricular failure FCHF / Pulmonary Edema FCardiogenic Shock

26. Localization: Definitive Therapy for Extensive AWMI H Normal blood pressure FThrombolysis may be indicated H Signs of shock FPTCA FCABG

27. Localization: LCA Occlusions H Other considerations FBundle branches supplied by LCA FSerious infranodal heart block may occur

28. Localization: Right Coronary Artery Right Coronary Artery Posterior Descending Artery Inferior Wall of left ventricle Posterior Wall Lateral Wall Left Ventricle Left Coronary Artery

29. Localization: Right Coronary Artery (RCA) H Proximal RCA occlusion FRight Ventricle injured FPosterior wall of left ventricle injured FInferior wall of left ventricle injured H Posterior descending artery (PDA) occlusion FInferior wall of right ventricle injured

30. Localization Practice ECG

31. Localization: Proximal RCA Occlusion H Right Ventricular Infarct (RVI) F12-lead ECG does not view right ventricle FUse additional leads W V3R - V6R W V4R FRight precordial leads W same anatomical landmarks as on left for V3 - V6 but placed on the right side

32. Localization Practice ECG Note: “R” designation manually placed on this ECG for teaching purposes

33. Localization: ECG Evidence of RVI H Inferior MI (always suspect RVI) H Look for ST elevation in right-sided V leads (V3-V6)

34. Localization: Physical Evidence of RVI H Dyspnea with clear lungs H Jugular vein distension H Hypotension FRelative or absolute

35. Localization: Treatment for RVI H Use caution with vasodilators FSmall incremental doses of MS FNTG by drip H Treat hypotension with fluid FOne to two liters may be required FLarge bore IV lines

36. Localization: Posterior Wall MI (PWMI) H Usually extension of an inferior or lateral MI FPosterior wall receives blood from RCA & LCA H Common with proximal RCA occlusions H Occurs with LCX occlusions H Identified by reciprocal changes in V1-V4 FMay also use Posterior leads to identify W V7: posterior axillary line level with V6 W V8: mid-scapular line level with V6 W V9: left para-vertebral level with V6

37. Localization Practice ECG

38. Localization: Left Coronary Dominance H Approximately 10% of population FLCX connects to posterior descending artery and dominates inferior wall perfusion H In these cases when LCX is occluded, lateral and inferior walls infarct FInferolateral MI

39. Localization Practice ECG

40. Localization Summary H Left Coronary Artery FSeptal FAnterior FLateral FPossibly Inferior H Right Coronary Artery FInferior FRight Ventricular Infarct FPosterior

41. Evolution of AMI H Hyperacute FEarly change suggestive of AMI FTall & Peaked FMay precede clinical symptoms FOnly seen in leads looking at infarcting area FNot used as a diagnostic finding

42. Evolution of AMI H Acute FST segment elevation FImplies myocardial injury occurring FElevated ST segment presumed acute rather than old

43. Evolution of AMI H Acute FST segment Elevated FQ wave at least 40 ms wide = pathologic FQ wave associated with some cellular necrosis

44. Evolution of AMI H Age Undetermined FWide (pathologic) Q wave FNo ST segment elevation FOld or “age undetermined” MI

45. AMI Recognition A normal 12-lead ECG DOES NOT mean the patient is not having acute ischemia, injury or infarction!!!

46. Practice

49. Reciprocal Changes

50. II, III, aVF I, aVL, V leads

51. Reciprocal Changes: Practice

53. AMI Recognition H Reciprocal changes FNot necessary to presume infarction FStrong confirming evidence when present FNot all AMIs result in reciprocal changes

54. Summary H ST segment elevation is presumptive evidence for AMI H Other conditions may also cause ST elevation FKnown as Imposters

55. Practice Case 1 H 48 year old male FDull central CP 2/10, began at rest H Pale and wet H Overweight, smoker H Vital signs: RR 18, P 80, BP 180/110, Sa0 2 94% on room air

56. Practice Case 1

57. Practice Case 2 H 68 year old female FSudden onset of anxiety and restlessness, FStates she “can’t catch her breath” FDenies chest pain or other discomfort H History of IDDM and hypertension H RR 22, P 110, BP 190/90, Sa0 2 88% on NC at 4 lpm

58. Practice Case 2

59. Practice Case Summary H Must take into Account FStory FRisk factors FECG FTreatment