Scott Hubbell, MHSc, RRT-NPS, C-NPT, CCT Clinical Education Coordinator/Flight RRT EagleMed

Transcription

1 Scott Hubbell, MHSc, RRT-NPS, C-NPT, CCT Clinical Education Coordinator/Flight RRT EagleMed

2 Identify the 12-Lead Views Explain the vessels of occlusion Describe the three I s Basic Interpretation of 12-Lead ECG s

3 Normal limb lead placement should be on wrists and ankles. Circumstance/Standing Orders/Protocol sometimes prevents that. Consistency is the key for a diagnostic ECG. Misplacement by 1 rib can mask a MI or make a normal ECG appear as if there is an MI.

4 Limb Lead Placement

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7 avr should be a negative deflection If avr is a positive deflection, check for reversed limb leads

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9 Look for: Negative avr One complete cardiac cycle in each lead Diagnostic frequency response Proper calibration Appropriate speed

10 Paper Speed

11 Know what to look for ST elevation > 1mm (some say 2mm) Two contiguous leads Know where you are looking Use ACLS ACS chart as a reference (last slide) You will soon have this memorized

12 I Lateral avr V1 Septal V4 Anterior II Inferior avl Lateral V2 Septal V5 Lateral III Inferior avf Inferior V3 Anterior V6 Lateral

13 I avr V1 V4 II avl V2 V5 III avf V3 V6

14 I avr V1 V4 II avl V2 V5 III avf V3 V6

15 I avr V1 V4 II avl V2 V5 III avf V3 V6

16 I avr V1 V4 II avl V2 V5 III avf V3 V6

17 I avr V1 V4 II avl V2 V5 III avf V3 V6

18 I avr V1 V4 II avl V2 V5 III avf V3 V6

19 Inferior Wall II, III, avf Left Leg I avr V1 V4 II avl V2 V5 III avf V3 V6

20 Inferior Wall I avr V1 V4 II avl V2 V5 III avf V3 V6 Inferior Wall

21 Lateral Wall I and avl Left Arm I avr V1 V4 II avl V2 V5 III avf V3 V6

22 Lateral Wall V5 and V6 Left lateral chest I avr V1 V4 II avl V2 V5 III avf V3 V6

23 Lateral Wall I, avl, V5, V6 Lateral Wall I avr V1 V4 II avl V2 V5 III avf V3 V6

24 Septal Wall V1, V2 Along sternal borders I avr V1 V4 II avl V2 V5 III avf V3 V6

25 Septal Wall V1,V2 I avr V1 V4 II avl V2 V5 III avf V3 V6

26 Anterior Wall V3, V4 Left anterior chest I avr V1 V4 II avl V2 V5 III avf V3 V6

27 Anterior Wall V3, V4 I avr V1 V4 II avl V2 V5 III avf V3 V6

28 Normal ECG

29 Practice

30 Practice

31 Practice

32 Practice

33 Practice

34 The Three I s Ischemia lack of oxygenation ST depression or T inversion Injury prolonged ischemia ST elevation Infarct death of tissue may or may not show in Q wave

35 Well Perfused Myocardium Epicardial Coronary Artery Septum Left Ventricular Cavity Lateral Wall of LV Positive Electrode Interior Wall of LV

36 Ischemia Epicardial Coronary Artery Septum Left Ventricular Cavity Lateral Wall of LV Interior Wall of LV Positive Electrode

37 Ischemia Inadequate oxygen to tissue Subendocardial Represented by ST depression or T inversion May or may not result in infarct

38 ST depression

39 Injury Thrombus Ischemia

40 Injury Prolonged ischemia Transmural Represented by ST elevation Usually results in infarct

41 ST elevation

42 Infarction Death of tissue Represented by Q wave Not all infarcts develop Q waves

43 Infarction Infarcted Area Electrically Silent Depolarization Many infarcts do not develop Q waves

44 Thrombus Infarcted Area Electrically Silent Ischemia Depolarization

45 Q Waves

46 Anatomy Revisited RCA right ventricle inferior wall of LV posterior wall of LV (75%) SA Node (60%) AV Node (>80%) LCA septal wall of LV anterior wall of LV lateral wall of LV posterior wall of LV (10%)

47 Left Coronary Artery Right Coronary Artery Right Ventricle Septal Wall Anterior Descending Artery Left Main Left Circumflex Lateral Wall Anterior Wall

48 Left Coronary Artery (LCA) Left Main (proximal LCA) Left Circumflex (LCX) Left Anterior Descending (LAD)

49 Distribution LAD = anteroseptal LCX = lateral Proximal LCA = extensive anterior

50 Practice ECG

51 Practice ECG

52 Practice ECG

53 Extensive Anterior MI Evidence in septal, anterior, and lateral leads Often from proximal LCA lesion Widow Maker Complications common

54 Definitive Therapy for Extensive AWMI Normal blood pressure Thrombolysis Signs of shock PTCA CABG

55 LCA Occlusions Other considerations Bundle branches supplied by LCA Serious infranodal heart block may occur

56 Right Coronary Artery Left Coronary Artery Lateral Wall Left Ventricle Right Coronary Artery Posterior Descending Artery Posterior Wall Inferior Wall

57 Right Coronary Artery (RCA) Proximal RCA Posterior descending artery (PDA)

58 RCA Distribution Proximal RCA Right ventricle Posterior wall Inferior wall PDA Inferior wall

59 Practice ECG

60 Proximal RCA Occlusion Right Ventricular Infarct (RVI) 12-lead ECG does not view right ventricle Use additional leads V3R - V6R V4R

61 Right Precordial Leads (Right sided ECG) On right side of chest Same anatomical landmarks as V3 - V6

62 Practice ECG

63 ECG Evidence of RVI Inferior MI (always suspect RVI) ST elevation right V leads

64 Cardiac Blood Flow To Lungs From Lungs To Body From Body

65 Physical Evidence of RVI Dyspnea with clear lungs Jugular vein distension Hypotension Relative or absolute

66 Treatment for RVI Use caution with vasodilators Small incremental doses of MS NTG by drip

67 Fluid for Hypotension One to two liters may be required Large bore lines suitable here

68 Posterior Wall MI (PWMI) Usually an extension of an inferior or lateral MI Common with proximal RCA occlusions Occurs with LCX occlusions

69 PWMI Reciprocal changes V1 - V4 Indicative changes V7, V8, V9

70 Posterior Leads V7 Posterior axillary line Level with V6 V8 Mid-scapular line Level with V6 V9 Left para-vertebral Level with V6

71 Indicative Leads ST Infarcted Tissue Q Posterior Wall Ischemic Tissue LV RV Reciprocal Leads R ST

72 PWMI Best to identify with direct leads V7, V8, V9 ST elevation in posterior leads is evidence of posterior MI

73 Practice ECG

74 Practice ECG

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