Chapter 6 - Introduction to 12 Lead Interpretation

BASE HOSPITAL GROUPONTARIO

Chapter 6 for 12 Lead Training

-Introduction to 12 Lead Interpretation-

Ontario Base Hospital GroupEducation Subcommittee

2008

TIME IS MUSCLE

OBHG Education Subcommittee

Introduction to 12 Lead Interpretation

REVIEWERS/CONTRIBUTORS

Neil Freckleton, AEMCA, ACPHamilton Base Hospital

Jim Scott, AEMCA, PCPSault Area Hospital

Ed Ouston, AEMCA, ACPOttawa Base Hospital

Laura McCleary, AEMCA, ACPSOCPC

Tim Dodd, AEMCA, ACPHamilton Base Hospital

Dr. Rick Verbeek, Medical DirectorSOCPC2008 Ontario Base Hospital Group

AUTHOR

Greg Soto, BEd, BA, ACPNiagara Base Hospital


Chapter 6 - Objectives

Recognize the usefulness of ECG data provided by computerized 12 Lead ECG

Identify important features of ECG such as Q, R, S, T waves and relate to 12 Lead interpretation

Find J-points and compare to TP segments Recognize ST-elevation and relate to clinical

significance Become comfortable with recognizing and

locating AMI on 12 Lead ECG Practice a bit of 12 Lead interpretation


12 Lead Interpretation

Interpretation vs. STEMI RecognitionIt is important to note that upon

completion of this training, it is not expected that paramedics will be “interpreting” a 12 Lead but rather recognizing STEMI patients


Learning 12 Lead ECG Interpretation

Common Paramedic responses prior to learning 12 Lead ECG Interpretation:

I can’t interpret a 12 Lead ECG like a Cardiologist!

Are you kidding me?

Common Paramedic responses after learning 12 Lead ECG Interpretation:

Hey – that wasn’t as hard as I thought it would be!


Essential Interpretation

GoalsRecognize and localize

AMI on the ECGFeel comfortable with 12

Lead interpretation


12 Lead ECG


12 Lead ECG


12 Lead ECG


R Wave


Q Wave


S Wave


J-Point


ST Segment


J point - end of QRS complex & beginning of ST segment

The J PointThe J Point


Practice

Find J-points and ST segments


Practice

Find J-points and ST segments


12-Lead ECG

AMI recognitionTwo things to know

What to look forWhere to look

Local medical oversight will determine the criteria used to identify a STEMI patient. All stakeholders must be consulted to determine what criteria should be utilized

in a given centre.


What to look for

Example - ST segment elevation One millimetre or more (one small

box) in limb leadsTwo millimetres or more (two small

boxes) in chest leadsPresent in two anatomically

contiguous leads


Contiguous Leads

Limb leads that “look” at the same area of the heart

OR

Numerically consecutive chest leads


Contiguous Leads

Inferior wall: II, III, avF Lateral wall: I, aVL, V5, V6 Septum: V1 and V2 Anterior wall: V3 and V4

Posterior wall: V7, V8, V9(leads placed on the patient’s back 5th

intercostal space creating a 15 lead EKG)


Where to look

ST segment elevation measurement0.04 seconds after J point


ST Segment Elevation


ST Segment Elevation

Presumptive evidence of AMI

Indication for acute reperfusion therapy


ST Segment

Compare to TP segment

ST TP


ST Segment Analysis


Practice


Lead “Views”


Limb Leads Chest Leads

I aVR V1 V4

II aVL V2 V5

III aVF V3 V6

Lead Groups


Lead “Views”


Inferior Wall

II, III, aVFLeft Leg

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Inferior Wall

Inferior Wall

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Lateral Wall

I and aVLLeft Arm

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Lateral Wall

V5 and V6Left lateral chest

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Lateral

I, aVL, V5, V6

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

Lateral Wall


Anterior Wall

V3, V4Left anterior chest

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Anterior Wall

• V3, V4V3, V4

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Septal Wall

V1, V2 Along sternal borders

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


Septal

• V1,V2V1,V2

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


AMI Localization

Anterior: V3, V4Anterior: V3, V4Septal: Septal: V1, V2V1, V2Inferior: Inferior: II, III, AVFII, III, AVFLateral:Lateral: I, AVL, V5, V6I, AVL, V5, V6

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


AMI Recognition

I Lateral

II Inferior

III Inferior

aVR

aVL Lateral

V1 Septal

aVF Inferior

V2 Septal

V3 Anterior

V4 Anterior

V5 Lateral

V6 Lateral


AMI Recognition

Know what to look forST elevation> 1mm in limb leads > 2mm chest leadsTwo contiguous leads

Know where you are lookingYou will soon have this memorized


Mnemonic for Location Rhyme, phrase or device for remembering

something “LII – LI – ASS (backwards) – ALL”

L = I (Lateral)I = II (Inferior)I = III (Inferior)L = aVL (Lateral)I = aVF (Inferior)

S = V1 (Septal)S = V2 (Septal)A = V3 (Anterior)A = V4 (Anterior)L = V5 (Lateral)L = V6 (Lateral)


Using mnemonic on ECG

You may want to write the Letters in the corner of each Lead when interpreting

L

L L

L

I

I I

S

S

A

A


Antero Septal


Extensive Anterior


Inferior


Extensive Anterior


Inferior


Extensive Anterior


Normal ECG


Inferior


Infero-lateral


Inferior


Inverted T-waves = ischemia


QUESTIONS?


Well Done!

Education Subcommittee

START QUIT

Chapter 6 - Introduction to 12 Lead Interpretation

Healthcare

obhg education subcommitteej

lead ecgpractice

lead ekg

lead trainingintroduction

st segments

v2anterior wall

v4posterior wall

avflateral wall