2 minute 12 leads v5
TRANSCRIPT
““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
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
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
Prehospital ECG Monitoring
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
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
Lead-Specific ST Elevation
• Anterior MI• Leads v3 and v4 visualize the anterior wall
of the heart’s left ventricle.
Lead-Specific ST Elevation
• 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
Lead-Specific ST Elevation
• 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
Injury/Infarct Recognition
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 !
Injury/Infarct Recognition
Thrombus
Ischemia
InjuryInjury
Injury/Infarct Recognition
Infarcted AreaElectrically Silent
Depolarization
Infarct
Injury/Infarct Recognition
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
ST Segment Elevation
• Other Causes:– Coronary Artery
Vasospasm [Prinzmetal’s Angina]
– Pericarditis [ all leads ]
– Ventricular aneurysm– Early repolarization
ST Segment Elevation
• 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
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
©Richard O. Cummins on behalf of AHA
Now let’s practice!Now let’s practice!
What’s your interpretation?
Anterior Septal AMI
What Does This 12-Lead ECG Show?
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?