2 minute 12 leads v5

““2 Minute 12 Leads”2 Minute 12 Leads”

John Bray, MA, NRP, CCEMTPMaster Instructor

Indian River State College

Why all the fuss?

• Because a 12-Lead shows a 3 dimensional view of the heart

• Because a simple 3-Lead shows a flat, 1 dimensional view (cartoon character)

• Infarcts can be hiding from a quick glance• 12-Lead is a true DIAGNOSTIC ECG

Cardiology Review

Anatomy Revisited

Localization: Right Coronary Artery

Right Coronary Artery

Posterior Descending Artery

Inferior Wall of left ventricle

Posterior Wall

Lateral Wall

Left Ventricle

Left Coronary Artery

Localization: Left Coronary Artery

Left Main

Left Circumflex

Lateral Wall

Anterior Wall of Left Ventricle

Septal Wall

Right Ventricle

Right Coronary Artery

Anterior Descending Artery

Anatomy Revisited

• SA node• Intra-atrial pathways• AV node• Bundle of His• Left and Right bundle

branches– left anterior fascicle– left posterior fascicle

• Purkinje fibers

Cardiac Conduction

Waveform Components: Q Wave

First negative deflection before R wave; Q wave includes the negative downstroke & return to baseline

Waveform Components: R Wave

First positive deflection; R wave includes the downstroke returning to the baseline

Waveform Components:S Wave

Negative deflection following the R wave; S wave includes departure from & return to baseline

Waveform Components: ST Segment

Segment between J-point and beginning of T wave

Waveform Components:QRS

• Q wave– Measure width– Pathologic if greater than or equal to 0.04 seconds (1

small box)

Waveform Components:J-Point

Junction between end of QRS and beginning of ST segment;

Waveform Components: ST Segment

• Need reference point– Compare to TP segment– DO NOT use PR segment as reference!

ST TP

Waveform Components: Practice

• Find J-points and ST segments

ST Segment Analysis

Which Segments are over 1mm high?

Obtaining the 12 Lead ECGObtaining the 12 Lead ECG

Lead “Views”

Prehospital ECG Monitoring

Check for Proper Calibration

“R” Wave Progression• Used to confirm proper lead placement

– V1 is small and progressively increasing from right to left until the QRS is fully upright in V5 and V6 The QRS size goes from negative to positive

Prehospital ECG Monitoring

InterpretationInterpretation

What can a 12 Lead find?

• Clots block distal blood flow

Coronary Artery Occlusion

Mapping the 12 Lead ECG

aVF inferiorIII inferior V3 anterior V6 lateral

aVL lateralII inferior V2 septal V5 lateral

aVRI lateral V1 septal V4 anterior

I See All Leads

• I – Inferior Leads II, III, AVF• S – Septal LeadsV1, V2• A – Anterior Leads V3, V4• L – Lateral Leads V5, V6, I, AVL

Recognition of AMI

• Focus on the ST Segment!!!

• ST elevation is the most important thing you are looking for!!

PR baseline

ST-segment deviation= 4.5 mm

J point plus0.04 second

Inferior Wall

• II, III, aVF– Left Leg

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Inferior Wall

Inferior Wall

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Lead-Specific ST Elevation

• Inferior MI• Leads II, III, aVF, visualize the inferior [ nearest the diaphragm ] surface of the heart• Leads are adjacent and view adjoining

tissues located in inferior region of the left ventricle

Septal Wall

• V1, V2• Along sternal borders

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Septal

• V1,V2V1,V2

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Anterior Wall

• V3, V4– Left anterior chest

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Anterior Wall

• V3, V4V3, V4

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6


• Anterior MI• Leads v3 and v4 visualize the anterior wall

of the heart’s left ventricle.


• Anterior MI• Rarely do MIs involve the anterior wall

exclusively, most often , either the septal or lateral walls of the ventricles are included.

Lateral Wall

• V5 and V6– Left lateral chest

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Lateral Wall

• I and aVL– Left Arm

IIIIII

aVRaVLaVF

V1V2V3

V4V5V6

Lateral

Lateral Wall

• I, aVL, V5, V6

I

II

III

aVR

aVL

aVF

V1

V2

V3

V4

V5

V6


• Lateral MI• Leads V3, V4, V5, and V6 will illustrate an

anterolateral MI • Leads II, III, aVF, v5, and v6 will illustrate an

inferolateral MI• Leads v5, and v6 only will illustrate a low

Lateral MI• Leads v5, v6, Lead I and aVL will illustrate a

High Lateral MI

Coronary Arteries

Semilunar valve

Aorta

RCA

Left Main

Septal

LADCXL

CXL

No ST elevation?Look for:

• Inverted T Waves• ST Depression

– Look for reciprocal changes• Q Waves

The Three I’s

• Ischemia– lack of oxygenation – ST depression or T inversion

• Injury – prolonged ischemia – ST elevation

• Infarct – death of tissue– may or may not show in Q wave

Injury/Infarct Recognition

Epicardial Coronary Artery

Lateral Wall of LV

Positive Electrode

Septum

Interior Wall of LV

Well Perfused Myocardium


Epicardial Coronary Artery

Lateral Wall of LVSeptum

Interior Wall of LV

Ischemia

Positive Electrode

Left Ventricular

Cavity

ST Segment Depression

• ST Segment Depression occurs due to Myocardial Ischemia

• Hypoxia results in altered repolarization

• Characterized by a dip below isoelectric line of 1 to 2 millimeters or 1 to 2 small boxes

ST Segment Depression

• Other Causes:– Ventricular

Hypertrophy– Intraventricular

Conduction defects– Medication: Digitalis– No irreversible injury

to the myocardium– TIME IS MUSCLE !


Thrombus

Ischemia

InjuryInjury


Infarcted AreaElectrically Silent

Depolarization

Infarct


Infarcted Area Electrically Silent

Thrombus

Depolarization

Ischemia

ST Segment Elevation

• ST Segment Elevation is a rise above the isoelectric line of 1 to 2 millimeters or one to two small boxes

• Most common cause is myocardial injury


• Other Causes:– Coronary Artery

Vasospasm [Prinzmetal’s Angina]

– Pericarditis [ all leads ]

– Ventricular aneurysm– Early repolarization


• Will occur within the first 1 to 2 hours after onset of myocardial hypoxia

• TIME IS MUSCLE

Pathologic Q Waves

• Pathologic Q Waves indicate irreversible tissue damage or death of myocardial tissue

• Defined as a width greater then or equal to one small box [ 1mm ] or depth greater then one third of the R wave in the same lead

EKG changes that occur at each stage of an MI

Reciprocal Changes

Reciprocal Changes

• ST in II, III, AVF

• ST in V2, V3, V4

• ST in V1-V4

• Reciprocal ST in I, AVL

• Reciprocal ST in II, III, AVF

• Reciprocal to Posterior– 15 Lead ECG

15 Lead ECG

• Posterior MI• Leads V1, V2, V3, and V4 will illustrate a posterior MI with ST

depression• Utilize Leads.

– Take V4, V5, and V6 and place them posteriorly in V7, V8, and V9. This is sometimes referred to as a 15-lead EKG.

• V4 is placed in the 5th intercostal space, posterior axillary position = V7.

• V5 is placed in the 5th intercostal space, midscapular line position = V8.

• V6 is placed in the 5th intercostal space, 2cm to the left of the spine

BUNDLE BRANCH BLOCKS

Bundle Branch Block

• Can be pre-existing condition

• Can be caused by ACS• If AMI caused

– 60-70% associated with pump failure

– 40-60% mortality w/o reperfusion

Bundle Branch Block

• May Produce– ST elevation– ST depression– Tall T waves– Inverted T waves– Wide Q waves

• May Hide– ST elevation– ST depression– Tall T waves– Inverted T waves– Wide Q waves

Can Mimic or Hide Evidence Needed to Identify AMI

BBB Problem

• BBB Problem

– ACS harder to identify on ECG when BBB present

– New or presumably new BBB is an indication for thrombolytic therapy

BBB Recognition

Forget About the Notch!

BBB Recognition

• Fundamental Criteria– Wide QRS

• > 100 ms (or, 0.10 sec)– Supraventricular rhythm

BBB Recognition

Normal Ventricular Conduction• Normal Conduction

– fibers of LBB begin conduction– impulse travels across interventricular

septum from left to right• towards + electrode creates small r wave

– travels across ventricles causing depolarization of both simultaneously

• LV contributes most to complex

– impulse travels away from + electrode creates primarily negative complex

RBBB

• RBBB in V1

R-S-R´

LBBB

• LBBB in V1

BBB Recognition

• Terminal Force in V1– direction of deflection prior to J point

J point

BBB Recognition

• Use V1• Find Terminal force• Identify direction of terminal force

– Downward LBBB– Upward RBBB

• Picture a Steering Wheel– Right turn turn signal goes up– Left turn turn signal goes down

BBB Recognition Practice

Axis & HemiblocksAxis & Hemiblocks

Axis and Hemiblocks• AXIS is defined as the general direction

that the electrical impulse travels down the heart

• Normal impulses should travel downward from R to L. This is shown in Lead I and VF as an upright QRS.

• Normal Range -30 to +90 DegreesNormal Range -30 to +90 Degrees

Left Axis Deviation

• Axis Range: 0 to –30 Degrees– Physiologic Left Axis Deviation (LAD)

• Axis Range: -30 to –90 Degrees– Pathological LAD– Anterior Hemiblock– Left BBB– May develop into Complete Heart Block!

Right Axis Deviation

• Ranges 90-180 Degrees• Downward QRS in Lead I

– Common in children and tall, thin adults– HX of COPD?

• Over 180 Degrees? Think V-TACH!!

Assess Initial 12-Lead ECG Findings

Classify patients with acute ischemic chest pain into 1 of the 3 groups above.

• ST elevation or new or presumably new LBBB:

strongly suspicious for injury

• ST-elevation AMI

• ST depression or dynamicT-wave inversion:

strongly suspicious for ischemia

• High-risk unstable angina/non–ST-elevation AMI

• Nondiagnostic ECG:absence of changes in ST segment or T waves

• Intermediate/low-riskunstable angina

OK, Great. So I see an infarct.

• You should be continuing your assessment but allow yourself no more than 2 minutes to analyze the 12 Lead ECG.

• After 2-3 mins, you may have to give repeat doses or other meds.

• Look for “trending”: How is the patient responding to treatment?

Medical ControlMedical Control

• Think about what you will say before getting on the phone.

• Understand that you are not a doctor, but that does not make you an idiot!

• Presentations should be given in plain English, not “EMS-speech”

Talking on the phone

• Present the patient in this order:– Identify yourself to the doctor– Give your pt’s age, sex and chief complaint– Describe how you found the patient– If unconscious, what was told to you by others– Patient’s medical Hx and Allergy status– Initial V/S– Pertinent Physical Exam findings

Still on the phone…

• Tell your interventions– Start with BLS and then ALS– Patient response to treatment

• Briefly discuss your 12 Lead findings– NOT an interpretation, but where you see

ST elevation• Give an ETA• Request further orders

IV Therapy and the MI Patient

• IV placement is important, but not vital!• Start with your PO and SL meds• Obtain a 12 Lead ECG• Start the IV

– Avoid more than 1 attempt– Think Thrombolytic Therapy!

Arrival at the ED

• Present patient as “Mr. or Mrs.” not “the chest pain” or “the heart attack”

• Have your 12 Lead out and ready for the doctor to review

• Answer questions that are posed to you!– Meds given– IV attempts (be truthful!)

What is Angioplasty?What is Angioplasty?

Three Percutaneous Coronary Interventions (PCIs)

1. PTCA: Percutaneous Transluminal Coronary

Angioplasty

2. PTCA + stent placement

3. Atherectomy: “grinds away” the

plaque

Now let’s practice!Now let’s practice!

What’s your interpretation?

Anterior Septal AMI

What Does This 12-Lead ECG Show?

Left Ventricular Hypertrophy

What Does This 12-Lead ECG Show?

Practice Case 1 • 48 year old male

– Dull central CP 2/10, began at rest

• Pale and wet

• Overweight, smoker

• Vital signs: RR 18, P 80, BP 180/110, Sa02 94% on room air

Practice Case 1

Practice Case 2• 68 year old female

– Sudden onset of anxiety and restlessness,– States she “can’t catch her breath”– Denies chest pain or other discomfort

• History of IDDM and hypertension

• RR 22, P 110, BP 190/90, Sa02 88% on NC at 4 lpm

Practice Case 2

Questions?

2 minute 12 leads v5

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