12-Lead 12-Lead ElectrocardiographyElectrocardiography

a comprehensive course

Adam Thompson, EMT-P, A.S.Adam Thompson, EMT-P, A.S.

Ischemia,

Injury, &

Infarct

(Part 1)

The 6-Step MethodThe 6-Step Method

• 1. Rate & Rhythm1. Rate & Rhythm

• 2. Axis Determination2. Axis Determination

• 3. Intervals3. Intervals

• 4. Morphology4. Morphology

• 5. STE-Mimics5. STE-Mimics

• 6. 6. Ischemia, Injury, & InfarctIschemia, Injury, & Infarct

STEMISTEMI

• STEMISTEMI– ST-Segment Elevated Myocardial InfarctionST-Segment Elevated Myocardial Infarction– ST-Segment Elevation of > 1mm in two contiguous ST-Segment Elevation of > 1mm in two contiguous

leads. leads. – In V2 & V3, ST-Segment elevation must be at least In V2 & V3, ST-Segment elevation must be at least

2mm.2mm.

*The smaller the QRS complex, the more significant minimal ST-*The smaller the QRS complex, the more significant minimal ST-

Elevation is.Elevation is.

Objectives

• Learn how to identify a STEMI

• Learn how to localize the infarcted area

• Apply everything learned thus far

What are Contiguous Leads?What are Contiguous Leads?

• Contiguous leads are leads that look at Contiguous leads are leads that look at the same area of the heart. the same area of the heart.

• They show up on the 12-lead proximal They show up on the 12-lead proximal to each other.to each other.

Lead I

lateral

aVR V1

septal

V4

anterior

Lead II

inferior

aVL

high lateral

V2

septal

V5

low lateral

Lead III

inferior

aVF

inferior

V3

anterior

V6

low lateral

Coronary Circulation

Left Main

Circumflex(LCx)

Left Anterior Descending(LAD)

Right Coronary Artery(RCA)

Coronary Circulation

Right Coronary Artery

(RCA)

Left Circumflex Artery

(LCx)

Left Anterior Descending

(LAD)

•Right Atrium•Inferior Wall•Inferior-Right Ventricle

•Posterior Wall - 85% of population

•Inferior Wall•Isolated Right Ventricle

•Posterior Wall - 15% of population

•Anterolateral•Inferolateral•Posterolateral

•Anterior•Anteroseptal•Anteroseptal-lateral

*Nicknamed “Widow-maker”

Coronary Occlusion

Heart Anatomy

Lateral Wall

Septal

Inferior

Anterior

Heart Anatomy

Epicardium

Endocardium

Myocardium

Ischemia, Injury, Infarct

ST-Elevation

• The most common cause of ST-elevation is not myocardial infarction.

• Less than 50% of STEMI alerts called by paramedics are actually Acute Coronary Syndrome (ACS) patients

ST-Elevation

• ST-Elevation is elevation of the J-Point which causes elevation of the following ST-Segment.

• Elevation is defined as anything above the isoelectric line.

• Find the isoelectric line by locating the TP-Segment.

T P

TP-Segment

ST-Elevation

• The J-Point is where the QRS complex and the ST-Segment meet.J-Point

ST-Segment Morphology

Concave Convex

J-Point J-Point

Part 1

• More up next…