Myocardial Ischemia / Injury /Infarction

Localization on ECG

ECG

Dr. UZMA ANSARI

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Using ECG one can localize the site of Ischemia / Injury/ Infarction.

Chief diagnostic tool to identify

Apr 11, 2023

Why Localize ?

Dr. UZMA ANSARI

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Anatomy Of heart

Surface Anterior left Inferior Base

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Apex – Left Ventricle

Borders

SURFACES OF HEART

Anterior: Right atrium, Right

ventricle partly by LV,LA.

LEFT: LV,LEFT

AURICLE

Inferior/Diaphragmatic:

2/3 by LV&1/3 by RV.

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Anatomy of Left ventricle

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According to new terminology infero posterior should be called infero basal

- Source: AHA

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Base/posterior surfase

Blood supplyRCA

Smaller Ant aortic sinus RA RV except area around

anterior I V groove Posterior I V Septum LV:small area around

posterior IV groove Entire conducting system

LCA Larger Lt post aortic sinus LA LV except area around

posterior IV groove Anterior I V septum RV:small area around

anterior IV groove Part of LBB

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LMCA Entire LV, LA, except the posterior portion of IV septal and adjacent area when PD is a branch of RCA

LAD • Anterior 2/3rd of IV septal• Anterior portion of LV• Whole apex

1st D (Branch of LCA)

High lateral wall of LV

2nd D Lower lateral aspect of LV freewall

1st Septal Superior and Anterior portion of IV septal

Minor Septal Inferior and anterior 1/3rd of septum

Ramus Inter ventricularis (From LCA)

Anterior aspect of apex

Dr. UZMA ANSARI

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LCX • 97% from LCA• 2% from Separate

Ostium• 1% RCA

Obtuse margin of heart and entire posterior wall. LA, posterior IV septum if PD arises from LCX

OM • 97% LCA Obtuse margin of heart adjacent to LV

Postero lateral branch

• 80% LCA• 20% RCA

Posterior and diaphragm LV wall

PD • 82% RCA• 18% LCA

Posterior IV septum and Diaphragm LV

Dr. UZMA ANSARI

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RCA RA and part of LA, RV, Posterio superior IV septum. SN, AV node

Acute Marginal Inferior and diaphragmatic surface of RV

Conus Branch Outflow track of RV

SN branch RA, LA,SN

RV Branch RV

Atrial Branch Right Atrium

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Localization - Left Coronary Artery (LCA)

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2004

LocalizationRight Coronary Artery (RCA)

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Localization Summary

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Prevalence of Culprit Artery

RCA 45%

LCX 12%

LAD 36%

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57%

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Prevalence of STEMI

Inferior 58%

Anterior 39%

Other 3%

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Post Ischemic T wave changes

ST elevation MI Non-ST Elevation Infarction

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ST depression, peaked T-waves, then T-wave inversion

ST elevation & appearance of Q-waves

ST segments and T-waves return to normal, but Q-waves persist

Ischemia

Infarction

Fibrosis

ST depression & T-wave inversion

ST depression & T-wave inversion

ST returns to baseline, but T-wave inversion persists

Infarction

Fibrosis

Ischemia

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Localization

Dr. UZMA ANSARI

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I Lateral

II Inferior

III Inferior

aVR

aVL Lateral

V1 Septal

aVF Inferior

V2 Septal

V3 Anterior

V4 Anterior

V5 Lateral

V6 Lateral

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The changes of ischemia/injury/infarction are seen in the leads

Over lying the area involved

Localization

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Inferior: II, III, AVFSeptal: V1, V2Anterior: V3, V4Lateral: I, AVL, V5, V6

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Frontal Plane Leads

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aVL -300

I

IIIII

00

aVF

-aVR

+900

+600

+1200

-1500

300

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Recommendations

aVL, Lateral

II, Inferior

V1 septal

V4 anterior

I,Lateral

aVF Inferior

V2 septal

V5 lateral

-aVR III, inferior

V3 anterior

V6 lateral

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- AHA guidelines

‘ECG machines should be equipped with switching systems that will allow the limb leads to be displayed and labelled appropriately in their anatomically contiguous sequence’

Apr 11, 2023

Localization - Myocardial Infarct Localization ST elevation

Reciprocal ST depression

Coronary Artery

Anterior MI V1-V6 None LAD

Septal Mi

V1-V4, disappearance of septum Q in leads V5,V6

none LAD

Lateral MI I, aVL, V5, V6 II,III, aVF (inferior leads)

LCX

Inferior MI II, III, aVF I, aVL (lateral lead)RCA (80%) or LCX (20%)

Posterior MI V7, V8, V9 high R in V1-V3 with ST depression V1-V3 > 2mm (mirror view)

RCA or LCX

Right Ventricle MI V1, V4R I, aVL RCA

Atrial MI PTa in I,V5,V6 PTa in I,II, or III RCA

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The localisation of the occlusion can be adequately visualized using a coronary angiogram (CAG).

Apr 11, 2023

Anterior Wall

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I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Septal

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

V1, V2◦ septum is left

ventricular tissue

Dr. UZMA ANSARI

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Septal Wall V1, V2

◦ Along sternal borders◦ Look through right ventricle & see

septal wall

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Practice 2

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Anteroseptal MI

ST elevations V1, V2, V3, V4

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Lateral Wall I and aVL

◦ View from Left Arm ◦ lateral wall of left ventricle

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Lateral Wall

V5 and V6◦ Left lateral chest◦ lateral wall of left ventricle

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Lateral Wall

I, aVL, V5, V6 ST elevation suspect lateral wall

injury

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Lateral Wall

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Lateral MI

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Localization - Extensive Anterior MI

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2004

Practice 1

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Anterior MI with lateral involvement

ST elevations V2, V3, V4

ST elevations II, AVL, V5

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Inferior Wall

II, III, aVF◦ View from Left Leg ◦ inferior wall of left ventricle

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6

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Inferior MI

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Practice 3

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Inferior MI

ST elevation 2,3 AVF

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Practice 4

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Inferior lateral MI

ST elevations 2, 3, AVF

ST elevations V5

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Posterior Leads Posterior leads V1, V2

Posterior Infarct with ST Depressions and/ tall R wave RCA and/or LCX Artery

ST elevation in V7,V8,V9. Understand Reciprocal changes

The posterior aspect of the heart is viewed as a mirror image and therefore depressions versus elevations indicate MI

Rarely by itself usually in combo.

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2004

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Localization Criteria:Occluded artery to the ECG

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Source: AHA

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Anterior wall MIOcclusion of LAD

ST , V1-V6 Occlusion above D1 and 1st SeptalBasal portion of LVAnterior and lateral wallInter-Ventricular SeptumST segment vector – superiorly and to left

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ST elevation ST depression

V1-V4, lead I, aVL, often in aVR

II, III, aVF (Inferior) often V5

aVL > aVR III > II

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Occlusion: Between 1st Septal and D1

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2004

Occlusion: More distally i.e. below Septal 1 and D1

Basal portion spared (ST vector directed inferiorly)

ST segment not elevated in I, aVL/aVR No depression in II, III, aVFIndeed, ST segment elevation in II,

III, aVF ST segment elevation more prominent in V3 –

V6 than V2

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Recommendation

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2004

Inferior MI ST Elevation in II,III,aVF

RCA OR LCX

ST III>II ST II>IIIST I,aVL ST I,aVL

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Whichever provides PD –Dominant artery

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Proximal RCA

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Right Ventricular Ischemia / Infarction

ST vector directed towards right and anteriorly inferiorly

ST elevation in right anterior leads i.e. V3R, V4R, sometimes V1

40% Associated with inferior M.I.ST elevation-V3R,V4R,V1,II,III,aVF

V4R

1.Most commonly used right sided lead2.Great value in diagnosing RV infarct along with IWMI3.Useful in distinguishing between RCA and LCX involvement 4.Between proximal and distal RCA occlusion5.V3R, V4R should be recorded as rapidly as possible because ST elevation in V3R, V4R remain for a shorter period of time in RWMI than ST elevation in extremity leads (II,III, aVF) in inferior MI

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Inferior MI +Posterior M.I.Lateral / Infero Lateral / Baso Lateral MI not postero

inferior MI. Proximal RCA OR LCX(posterior+inferior) Posterior+Inferior MI + RV infarct

ST II,III,aVF,aVL,I ST II,III,aVF ST ,tall R V1,V2,V3,

ST I,aVL ST II>III

ST V3R,V4R ST III>II

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Multiple infarctMulti vessel.

Anterior+inferior inferior+posterior

anterior+lateralOld+new

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Multiple Ischemia / Infarction / Injury

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ST depression in multiple leads in absence of elevation

Subendocardial ischemia / injury at multiple region due to multi vessel disease

ST depression in more than / equal to 8 leads along with ST elevation in aVR and / or V1Indicates 75% chances of 3 vessel disease / LMCA stenosis

Source: AHA

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In some cases, Deep T wave ( > 0.5 mV ) in V2, V3, V4 with prolong QT after an episode of chest pain without evidence of Ischemia / Injury / Infarction

(i.e. T wave morphology similar to CVA)

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CAG

Severe stenosis of proximal LAD

If missed and not treated, it could lead to AWMI

So, If we get deeply inverted T wave (> 0.5 mV) with prolonged QT, one should suspect Severe stenosis of proximal LAD with / without CVA

Appropriate treatment

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Thank You

Dr. UZMA ANSARI

56 Apr 11, 2023