12 Lead Electrocardiogram (ECG) PFN: SOMACL17

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Slide 1JSOMTC, SWMG(A)

12 Lead Electrocardiogram (ECG) PFN: SOMACL17


Terminal Learning Objective

Action: Communicate knowledge of 12 Lead Electrocardiogram (ECG)

Condition: Given a lecture in a classroom environment

Standard: Received a minimum score of 84% on the written exam IAW course AHA standards


References

Advanced Cardiovascular Life Support, Provider Manual 2010

The 12 lead ECG in Acute Myocardial Infarction 1996

The 12 lead ECG for Acute and Critical Care Providers 2005

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Reason

Ischemic heart disease causes the greatest number of deaths in the United States.

50% die before arriving at a hospital.

If treatment is not received within 2 hours of onset of symptoms, chance of survival is 25%.

By treating a heart attack within one hour of onset of symptoms, the chance of survival is 49%!


Reason

The keys to quick management of an acute myocardial infarction (AMI) patient are:

Prompt recognition of the symptoms

Rapid performance and interpretation of a 12 Lead ECG

Provide pre‐arrival notification to the receiving facility


Agenda

Recall the pathophysiology of acute myocardial infarction (AMI)

Identify the electrode placement for a 12 Lead ECG

Identify the 12 Lead ECG physiology to assess an AMI

Identify an AMI using a 12 Lead ECG

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Agenda

Identify the limitations and complications of recognizing an AMI using a 12 Lead ECG

Participate in a 12 Lead ECG interpretation practical exercise


Pathophysiology of Acute Myocardial Infarction (AMI)


Pathophysiology of AMI

A heart attack occurs when a thrombus or blood clot forms in a coronary artery, cutting off the blood supply to a segment of the heart muscle.

Prompt restoration of blood flow can stop and minimize (or even prevent) the heart damage.

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The blood flow can be restored by:

Percutaneous coronary intervention (PCI)

Coronary artery bypass graft (CABG)

Administration of a clot dissolving (thrombolytic) drug



ACS symptom review:

Crushing chest pain lasting more than 15 minutes

Chest Pain spreading to the shoulders, neck, arms or jaw

Chest discomfort with lightheadedness, fainting, sweating or nausea

Shortness of breath with or without chest discomfort


Electrode Placement for a 12 Lead ECG

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ECG Leads

Bipolar

Leads I, II, and III

Unipolar

Leads aVR, aVL, and aVF

Precordial

V1, V2, V3, V4, V5, and V6


12 Lead ECG Preparation


Bipolar and Unipolar Leads

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Precordial Leads


V1


V2

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V4


V3


V5

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V6


12 Lead ECG Electrode Placement


12 Lead ECG Physiology to Assess an AMI

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12 Lead ECG Relationship to Coronary Artery Anatomy

Let’s look at the heart

Page 28 in the ACLS Handbook

The right coronary artery (RCA) supplies oxygen to the inferior (bottom) surface of the heart



The left coronary artery (LCA) splits in two:

The left anterior descending coronary artery (LAD)

The left circumflex coronary artery (LCX or Cx)


12 Lead ECG Relationship to Coronary Artery Anatomy (cont)

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The left anterior descending coronary artery (LAD) courses down the anterior (front) surface of the heart and supplies oxygen to the septal, anterior, and lateral sides of the heart.





The left circumflex coronary artery (Cx) supplies oxygen to the left lateral (side) surface of the heart.

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aVF inferiorIII inferior V3 anterior V6 lateral

aVL lateralII inferior V2 septal V5 lateral

aVRI lateral V1 septal V4 anterior

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Identify an AMI Using a 12 Lead ECG


Analyze the 12 Lead ECG

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Normal 12 Lead ECG


12 Lead Versus 3 Lead ECG

Differences

2.5 second views instead of a 6 second view

Legend

Views mimic anatomy of the heart


Identify an AMI

Baseline

Ischemia—tall or inverted T wave (infarct),ST segment may be depressed (angina)

Injury—elevated ST segment, T wave may invert

Infarction (Acute)—abnormal Q wave,ST segment may be elevated and T wavemay be inverted

Infarction (Age Unknown)—abnormal Q wave,ST segment and T wave returned to normal

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ECG Recording


Identify an AMI

Know what to look for: Measure from J point

ST elevation or depression >1 mm

2 anatomical leads

Pathologic Q wave greater than 40 ms or greater than 1/3 height of R wave PR baseline

ST‐segment deviation= 4.5 mm

J point plus0.04 second


ST Segment Elevation Myocardial Infarctions (STEMIs)

Acute Anterior Wall Infarct

Anterolateral Infarct

Acute Inferior Wall Infarct

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Acute Anterior Wall Infarct


Anterolateral Infarct


Acute Inferior Wall Infarct

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Limitations and Complications of Recognizing an AMI Using a

12 Lead ECG


Limitations of 12 Lead ECG

12 Lead ECG:

Does not look at the right ventricle of the heart

• Acute Right Ventricular Infarct

Does not look at the posterior (rear) of the heart

• Posterior Wall Infarct

Patient can still be having an AMI even if ST elevation is not seen on a 12 lead ECG


Right Ventricular Infarct

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Right Ventricular Infarct

Looks just like an inferior infarct

Take lead V4 and place it 5th ICS MCL on the right side of the chest

RVI suspected if ST elevation is present in that lead

Usually this patient is in cardiogenic shock due to a heavy reliance on preload

Don’t administer Nitro or Morphine


Posterior Wall Infarct


Posterior Wall Infarct

ST segment depression is reciprocal of ST segment elevation

Taller R wave is reciprocal of pathological Q wave

Usually noticed in leads V1, V2, and V3

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Complications of 12 Lead ECG

AMI can affect the conduction system of the heart

New Left Bundle Branch Block

Lethal Dysrhythmias

Examples: VF or Pulseless VT

Cardiogenic Shock


Left Bundle Branch Block



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Look at the QS complex in V1

QRS > 0.12 seconds

Pointing down indicates LBBB


12 Lead ECG Interpretation Practical Exercise


Practical Exercise

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Questions?


Terminal Learning Objective

Action: Communicate knowledge of 12 Lead Electrocardiogram (ECG)

Condition: Given a lecture in a classroom environment

Standard: Received a minimum score of 84% on the written exam IAW course AHA standards


Agenda

Recall the pathophysiology of acute myocardial infarction (AMI)

Identify the electrode placement for a 12 Lead ECG

Identify the 12 Lead ECG physiology to assess an AMI

Identify an AMI using a 12 Lead ECG

21


Agenda

Identify the limitations and complications of recognizing an AMI using a 12 Lead ECG

Participate in a 12 Lead ECG interpretation practical exercise


Reason

Ischemic heart disease causes the greatest number of deaths in the United States.

50% die before arriving at a hospital.

If treatment is not received within 2 hours of onset of symptoms, chance of survival is 25%.

By treating a heart attack within one hour of onset of symptoms, the chance of survival is 49%!


Reason

The keys to quick management of an acute myocardial infarction (AMI) patient are:

Prompt recognition of the symptoms

Rapid performance and interpretation of a 12 Lead ECG

Provide pre‐arrival notification to the receiving facility

Documents

12 Lead Electrocardiogram (ECG) PFN: SOMACL17