Download 12 Lead ECG Interpretation * Part 3

Understanding ST Elevation MI’s & the
Associated Pathology
• Justify treatment choices based on assessment findings and the
associated pathophysiology affecting patients suffering a
cardiovascular emergency.
• Correspond the area of ischemia or injury to the findings on a
12 lead ECG.
• Recognize the indications and contraindications for medication
administration based on ECG findings.
• Feeds blood supply to:
• Right ventricle
• Inferior wall and posterior
wall of the left ventricle
• SA node in 55% of people
• AV nodes in 90% of people
• Don’t forget the posterior
fascicle of the LBB
• LAD feeds –
• Anterior wall of the left
ventricle
• Intraventricular septum
• RBB, LBB, and both fascicles
of the LBB
• Left Circumflex Branch
feeds –
• Lateral and posterior walls
of the left ventricle
• SA node in 45% of patients
• AV nodes 10% of patients
• ST segment elevation
• T wave inversion or ST segment
depression
• Pathologic Q waves
• Indicators:
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Injury
ST segment elevation greater than 1mm (2mm is septal leads)
Present in two or more related or contiguous leads
Measure at J point to baseline
• ST elevation = acute transmural injury (all three layers of the
heart are damaged)
• ST depression is considered reciprocal to the elevation and
confirms the diagnosis of an MI
• Causes of ST depression:
• Reciprocal to ST elevation
• Ischemia or subendocardial injury
• Certain meds such as digitalis
• ST depression without ST elevation
• Ischemia or injury to the subendocardial wall
• A single layer of heart muscle.
Page, R. (2005). 12-lead ECG for acute and critical care
providers. Upper Saddle River, N.J.: Pearson Prentice Hall.
• Early sign of ACS and myocardial ischemia
• BASELINE 12 lead should be ascertained before NTG administration
• NTG can reverse/reperfuse ischemia thus removing ST changes
• NTG can be diagnostic in proving the existence of ACS
• Signifies infarction, or death of tissue
• Q wave must be more than 40ms wide (0.04sec) or a third the
R wave height to be pathological
• IF seen with ST elevation, indicates acute ongoing myocardial
infarction.
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I
Inferior
See Septal
All
Anterior
Leads Lateral
I Inferior
II, III, aVF
S Septal
V1, V2
A Anterior
V3, V4
L Lateral
V5, V6, I, aVL
STEMI
Vessel
Leads
Reciprocal Leads
I Inferior
RCA
II, III, aVF
I, aVL
S Septal
LAD
V1, V2
A Anterior
LAD
V3, V4
II, III, aVF
L Lateral
Circumflex
V5, V6, I, aVL
II, III, aVF
I
Lateral
aVR
V1
Septum
V4
Anterior
II
Inferior
aVL
Lateral
V2
Septum
V5
Lateral
III
Inferior
aVF
Inferior
V3
Anterior
V6
Lateral
Page, R. (2005). 12-lead ECG for acute and critical care
providers. Upper Saddle River, N.J.: Pearson Prentice Hall.
I
Lateral
aVR
V1
Septum
V4
Anterior
II
Inferior
aVL
Lateral
V2
Septum
V5
Lateral
III
Inferior
aVF
Inferior
V3
Anterior
V6
Lateral
I
Lateral
aVR
V1
Septum
V4
Anterior
II
Inferior
aVL
Lateral
V2
Septum
V5
Lateral
III
Inferior
aVF
Inferior
V3
Anterior
V6
Lateral
Page, R. (2005). 12-lead ECG for acute and critical care
providers. Upper Saddle River, N.J.: Pearson Prentice Hall.
I
Lateral
aVR
V1
Septum
V4
Anterior
II
Inferior
aVL
Lateral
V2
Septum
V5
Lateral
III
Inferior
aVF
Inferior
V3
Anterior
V6
Lateral
Page, R. (2005). 12-lead ECG for acute and critical care
providers. Upper Saddle River, N.J.: Pearson Prentice Hall.
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Overview of the patient presentation
Interpretation of the 12 Lead
Identify the area of the cardiac system affected
Describe how that damage may reflect in the patient’s case
• Table 1: Provide basic information provided from the case
• Human Body Picture: can be used (if you like) to outline areas
as ill/injured or treatments given.
• Heart Picture: Circle the area of the heart in the picture that is
affected.
• Next to the heart picture: Provide a thorough run down of all
treatments that will be provided to this case presentation.
• Table 2: List the individual names of the medications used, total
dosages given, body system(s) affected and the action of the
medications.
Pictures from: Course
Text-Bob Page: 12 Lead
ECG Interpretation
textbook, Microsoft clip
art, and Personal ECG
stock
P. Johnson; BA, NCEE, NRP, WV-MCCP