Presentation is loading. Please wait.

Presentation is loading. Please wait.

1 12-Lead EKG MEPN Level IV. 2 Discuss the changes in T wave and ST segment morphology with an MI List the criteria for identification of right or left.

Similar presentations

Presentation on theme: "1 12-Lead EKG MEPN Level IV. 2 Discuss the changes in T wave and ST segment morphology with an MI List the criteria for identification of right or left."— Presentation transcript:

1 1 12-Lead EKG MEPN Level IV

2 2 Discuss the changes in T wave and ST segment morphology with an MI List the criteria for identification of right or left bundle branch blocks. List the anatomically congruent leads associated with an inferior, lateral and anterior wall MI Describe morphology of Q wave presence EISLOs

3 3 Myocardial A&P

4 4 Heart wall - Three layers Epicardium (outer) visceral layer of pericardium thin, transparent smooth, slippery Myocardium (middle) mass of cardiac muscle Endocardium (inner) endothelium over thin connective tissue smooth lining for the chambers and valves continuous with blood vessel endothelium

5 5

6 6 Cardiac Enzymes Myoglobin –Released by all striated muscle –Rises fast (2 hours) after myocardial infarction –Peaks at hours –Returns to normal in hours CK –Released by all muscles in the body –Rises in 4-6 hours after injury –Peaks in 24 hours –Returns to normal in 3-4 days –CK-MB is myocardial specific Peaks in 3-4 hours Returns to normal in 2 days Troponin –More specific for myocardial injury –Rises 2-6 hours after injury –Peaks in 12 hours –Remains elevated for 5-14 days

7 7 Arteries first branches off the aorta blood moves more easily into the myocardium when it is relaxed between beats during diastole blood enters coronary capillary beds CoronaryBloodFlow

8 8 Collateral Circulation

9 9

10 10 Coronary Circulation

11 11 Coronary Circulation Pathologies Compromised coronary circulation due to: emboli: blood clots, air, amniotic fluid, tumor fragments fatty atherosclerotic plaques smooth muscle spasms in coronary arteriesProblems ischemia (low supply of nutrients) hypoxia (low supply of O 2 ) infarct (cell death)

12 12 Internodal tracts Bundle of His Right Bundle Branch

13 13 SA Node

14 14 Intranodal Pathways

15 15 AV Node Conduction Normal conduction pathway from atria to ventricles Limits number of atrial impulses sent to the ventricles

16 16 Bundle Branches

17 17 Action Potential Phase 0 Begins at -70 mV with a slow influx of sodium ions; gradually raising the potential toward threshold When threshold is reached fast sodium channels open; causing the cell to fire Phase 1 Rapid sodium pumps are slowed by influx of potassium Phase 2 Plateau phase Sodium influx slows; calcium begins to enter the cell Calcium stimulates cellular contraction by stimulating the myocyte Phase 3 Reverse pumps open; rapid repolarization Phase 4 Back to the -70 mV resting potential

18 18 Myocardial Action Potential Depolarization Phase 1 of the action potential Stimulation of the cardiac cell by the pacemaker cell causing an influx of Na and Ca, outflow of K. Repolarization Phase 2 of the action potential No impulse entering the cells can cause it to depolarize Relative refractory period Phase 3 of the action potential Impulses entering the cardiac cell now can cause serious, uncontrolled reactions. Absolute refractory period Phase 4 of the action potential The return of the cardiac cells to resting state.

19 19 EKG Basics 25 mm per sec Each small box - horizontally = 0.4 sec Each small box - vertically = 1 mm

20 20 EKG Review - Analysis Rhythm Regular or irregular Rate Too fast, too slow, just right P waves Upright, inverted, not there, not related P-R Interval ; >0.20; <0.12 QRS complex <0.12 QT Interval

21 21 P wave: Represents positive and negative deflections of atrial contraction and relaxation PR Interval: Distance between the P wave and the Q/R wave QRS Complex: represents ventricular depolarization Q wave: First negative deflection R Wave: First positive deflection S Wave: second negative deflection ST Segment: Essentially isoelectric, slopes gently upward Normal >.08 sec J point: the point where the S wave meets the isoelectric line T Wave: Ventricular repolarization always upright in leads I, II, V2-V6 aVR is always negative. Leads III, aVL, aVF, and V1 can be positive or negative U Wave: unclear etiology, commonly seen in V2-V3 due to proximity to ventricular mass; common in bradycardia, hypokalemia, digitalis

22 22 QT interval beginning of the QRS complex to the end of the T wave represents ventricular depolarization and repolarization ---- Changes with heart rate QTc QT corrected for heart rate QT / R-R = QTc Evaluates the recovery of the ventricle

23 23 ECG Leads 6 limb leads (frontal plane)6 limb leads (frontal plane) –3 bipolar leads –3 unipolar leads 6 precordial leads (horizontal plane)6 precordial leads (horizontal plane) –V1 – V6

24 24 Lead I RA (-) to LA (+) Lead II RA (-) to LL (+) Lead III LA (-) to LL (+) Einthovens Triangle Limb Leads BIPOLAR

25 25 AUGMENTED (UNIPOLAR) LEADS Augmented leads combine 2 leads together (the null point) from the center point of the triangle with one positive pole. aVR aVR (Augmented Voltage Right Arm positive) is a combination of bipolar Leads I and II aVL aVL (Augmented Voltage Left Arm Positive) is a combination of I and III aVF aVF (Augmented Voltage Left Foot positive) is a combination of Bipolar Leads II and III


27 27 Precordial Lead Placement V1 – 4 th intercostal space right of sternum V2 - 4 th intercostal space left of sternum V4 – 5 th intercostal space midclavicular line V3 – midway between V2 and V4 V6 – 5 th intercostal space midaxillary line V5 – same level as V4 at anterior axillary line between V4 and V6

28 28 RIGHT SIDED EKG Same lead position as left side – looks directly at the Right ventricle

29 29 Posterior View Posterior leads: V7 – lateral to V6 at posterior axillary line V8 – level of V7 at the mid-scapular line V9 – level of V8 at the paravertebral line (left posterior thorax midway from spine to V8)

30 30

31 31 V3 & V4 V1 & V2 V5 & V6 PRECORDIAL LEADS

32 32 calibration calibration marker Bottom line is continuous strip LIMB LEADS AUGUMENTED LEADS PRECORDIAL LEADS

33 33 R – Wave Progression

34 34 R – Wave Progression

35 35 Myocardial ischemia Various definitions are used. The term commonly refers to diffuse ST segment depression, usually with associated T wave inversion Myocardial injury Injury always points outward from the surface that is injured with ST segment elevation Myocardial infarction death of heart muscle

36 36 Ischemia, Injury, Infarction Waveforms

37 37 ST segment should be electrically neutral ST Segments

38 38 Visual aid in determining: –Ischemia or injury to myocardium –Normal should be at baseline –Depressed ST segment - >2 mm below baseline

39 39

40 40 EKG 1

41 41 ST Segment Elevation ST segment elevation is attributed to impending infarction –but can also be due to pericarditis or vasospastic (variant) angina. The height of the ST segment is measured at a point 2 boxes after the end of the QRS complex –significant if it exceeds 1 mm in a limb lead or 2 mm in a precordial lead.

42 42 EKG 2

43 43 T Waves T waves are normally positive in leads with a positive QRS T waves are normally asymmetrical T waves are normally not more than 5 mm high in limb leads or 10 mm high in precordial leads or 2/3 the height of the R wave

44 44 T wave Hyperkalemia Ischemia

45 45 Hyperkalemia EKG 3

46 46 ST-T Wave Combination of infarction and often hyperkalemia Tombstone TCalled Tombstone T because of the shape. Usually a sign of impending cardiac death.

47 47 EKG 4Inferior-Anterior-Lateral

48 48 Pathology of an MI

49 49 Localization of ECG Pathology InferiorInferior: Abnormalities that appear in leads II, III, and aVF (called the inferior leads) indicate pathology on the inferior or diaphragmatic surface of the heart. Lateral:Lateral: Leads I, aVF, and V5-V6 are called lateral leads. Abnormality in these leads indicates pathology on the lateral, upper surface of the heart. Anterior:Anterior: Anterior pathology is seen in leads V1-V4, and often in lead I.

50 50 Overview of Infarcts Location of Infarct Arterial Supply Indicative Changes Reciprocal Changes Anterior LADV1-V4II, III, aVF Inferior RCAII, III, aVFI, aVL Lateral CircumflexI, aVL V5, V6 V1 Posterior Posterior Descending (RCA) V7, V8, V9 - elevation V1, V2 - ischemia Septal Septal Perforating (LAD) Posterior Descending (RCA Possible loss of R wave in V1, V2, V3 None

51 51 Pathological Q Wave ST Segment Elevation Q Q Q ST T T T Wave Elevation T Wave Inversion T

52 52 EKG Changes from Infarction First Detectable Change in EKG Tall T-waves increase in height more symmetric may occur in the first few minutes Hyper-acute Phase

53 53 Acute Phase ST Segment Elevation Primary indication of injury Occurs in first hour to hours ST Segment Elevation in Leads 1mm or greater in limb leads 2 mm or greater in chest leads Hallmark indication of AMI

54 54


56 56

57 57

58 58

59 59

60 60

61 61

62 62

63 63

64 64

65 65 Leads II, III, aVF -Looks at inferior heart wall Inferior View of Inferior Heart Wall

66 66 Inferior EKG 5

67 67 Inferior EKG 6

68 68 Leads I and aVL –Looks at lateral heart wall –Looks from the left arm toward heart Lateral View of Lateral Heart Wall *Sometimes referred to as High Lateral or High Apical view*

69 69 Leads V5 & V6 –Looks at lateral heart wall –Looks from the left lateral chest toward heart Lateral View of Lateral Heart Wall *Sometimes referred to as Low Lateral or Low Apical view*

70 70 Leads I, aVL, V5, V6 - Looks at the lateral wall of the heart from two different perspectives Lateral View of Entire Lateral Heart Wall Lateral Wall

71 71 Lateral EKG 7

72 72 Lateral EKG 8

73 73 Leads V3, V4Leads V3, V4 –Looks at anterior heart wall –Looks from the left anterior chest Anterior View of Anterior Heart Wall

74 74 Anterior EKG 9

75 75 EKG 10

76 76 Leads V1, V2 -Looks at septal heart wall -Looks along sternal borders Septal View of Septal Heart Wall


78 78 Q Waves DefinitionDefinition –Septal depolarization –Normally present in I, aVL, V6

79 79 Two types of Q waves –Non-pathologic Narrow, shallow Q waves Not visible in all leads –Pathologic > 0.04 in duration; at least 1/4 to 1/3 height of R wave Represent an infarcted area of myocardium


81 81 Bundle Branch Blocks If the QRS duration is >.12 there is usually an abnormality of conduction of the ventricular impulse

82 82 RBB Block Most common ventricular conduction defect Can be acute or chronic Acute RBBB is associated with an acute anterior MI

83 83 EKG 11 RBBB

84 84 LBB Block Always indicates a diseased heart More common in older adults

85 85 EKG 12 LBBB

86 86

Download ppt "1 12-Lead EKG MEPN Level IV. 2 Discuss the changes in T wave and ST segment morphology with an MI List the criteria for identification of right or left."

Similar presentations

Ads by Google