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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.

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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 OBJECTIVES

3 3

4 4 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

5 5 Lead I RA (-) to LA (+) Lead II RA (-) to LL (+) Lead III LA (-) to LL (+) Einthovens Triangle Limb Leads BIPOLAR

6 6 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


8 8 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

9 9 RIGHT SIDED EKG Same lead position as left side – looks directly at the Right ventricle

10 10 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)

11 11

12 12 V3 & V4 V1 & V2 V5 & V6 PRECORDIAL LEADS

13 13 calibration calibration marker Bottom line is continuous strip LIMB LEADS AUGUMENTED LEADS PRECORDIAL LEADS

14 14 R – Wave Progression

15 15 R – Wave Progression

16 16 Myocardial ischemiaMyocardial ischemia –Various definitions are used. The term commonly refers to diffuse ST segment depression, usually with associated T wave inversion Myocardial injuryMyocardial injury –Injury always points outward from the surface that is injured with ST segment elevation

17 17 Ischemia, Injury, Infarction Waveforms

18 18 ST segment should be electrically neutral ST Segments

19 19 Visual aid in determining: –Ischemia or injury to myocardium –Normal should be at baseline –Depressed ST segment - >2 mm below baseline

20 20

21 21 EKG 1

22 22 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.

23 23 EKG 2

24 24 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

25 25 T wave Hyperkalemia Ischemia

26 26 Hyperkalemia EKG 3

27 27 ST-T Wave Combination of infarction and often hyperkalemia Tombstone TCalled Tombstone T because of the shape. Usually a sign of impending cardiac death.

28 28 EKG 4

29 29 Pathology of an MI

30 30 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.

31 31 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) NoneV1, V2 Septal Septal Perforating (LAD) Posterior Descending (RCA Loss of R wave in V1, V2, or V3 None

32 32 Pathological Q Wave ST Segment Elevation Q Q Q ST T T T Wave Elevation T Wave Inversion T

33 33 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

34 34 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

35 35

36 36 Leads II, III, aVF -Looks at inferior heart wall View of Inferior Heart Wall

37 37 Inferior EKG 5

38 38 Inferior EKG 6

39 39 Leads I and aVL –Looks at lateral heart wall –Looks from the left arm toward heart View of Lateral Heart Wall *Sometimes referred to as High Lateral or High Apical view*

40 40 Leads V5 & V6 –Looks at lateral heart wall –Looks from the left lateral chest toward heart View of Lateral Heart Wall *Sometimes referred to as Low Lateral or Low Apical view*

41 41 Leads I, aVL, V5, V6 - Looks at the lateral wall of the heart from two different perspectives View of Entire Lateral Heart Wall Lateral Wall

42 42 Lateral EKG 7

43 43 Lateral EKG 8

44 44 Leads V3, V4Leads V3, V4 –Looks at anterior heart wall –Looks from the left anterior chest Anterior View of Anterior Heart Wall

45 45 Anterior EKG 9

46 46 Anterior EKG 10

47 47 Leads V1, V2 -Looks at septal heart wall -Looks along sternal borders View of Septal Heart Wall


49 49 Q Waves DefinitionDefinition –Septal depolarization –Normally present in I, aVL, V6

50 50 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


52 52 Bundle Branch Blocks If the QRS duration is >.12 there is usually an abnormality of conduction of the ventricular impulse

53 53 RBB Block Most common ventricular conduction defect Can be acute or chronic Acute RBBB is associated with an acute anterior MI

54 54 EKG 11 RBBB

55 55 LBB Block Always indicates a diseased heart More common in older adults

56 56 EKG 12 LBBB

57 57

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