12 lead-lesson 3
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Transcript of 12 lead-lesson 3
12-Lead 12-Lead ElectrocardiographyElectrocardiography
a comprehensive course
Adam Thompson, EMT-P, A.S.Adam Thompson, EMT-P, A.S.
Lesson
3
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. Ischemia, Injury, & Infarct6. Ischemia, Injury, & Infarct
Lesson ThreeLesson Three
• Examining Intervals and MorphologiesExamining Intervals and Morphologies– Bundle Branch BlocksBundle Branch Blocks– WPWWPW– Chamber EnlargementChamber Enlargement– Hyperkalemia/HypokalemiaHyperkalemia/Hypokalemia– HypothermiaHypothermia– Long QT SyndromeLong QT Syndrome– Digitalis ToxicityDigitalis Toxicity
ObjectivesObjectives
• Review normal intervals & morphologiesReview normal intervals & morphologies• Learn how to identify BBB’s.Learn how to identify BBB’s.• Learn how to identify atrial enlargement or Learn how to identify atrial enlargement or
ventricular hypertrophy.ventricular hypertrophy.• Learn how to identify WPW or LGL.Learn how to identify WPW or LGL.• Learn how to identify electrolyte Learn how to identify electrolyte
derangements.derangements.
PR-IntervalPR-Interval
• PR-IntervalPR-Interval– > 120ms> 120ms– < 200ms< 200ms
P-WaveP-Wave
• Normal height < 2.5mm (2 1/2 small boxes)Normal height < 2.5mm (2 1/2 small boxes)• Normal width < 0.10 seconds (2 1/2 small boxesNormal width < 0.10 seconds (2 1/2 small boxes
P-WaveP-Wave
P-WaveP-Wave
• P-MitraleP-Mitrale– Indicates left atrial Indicates left atrial
enlargement.enlargement.– A notched P-wave gretaer A notched P-wave gretaer
than 0.12 seconds.than 0.12 seconds.– A biphasic P-wave in V1 that A biphasic P-wave in V1 that
is deeper than it is tall.is deeper than it is tall.
V1
II
P-Mitrale
P-WaveP-Wave
• P-PulmonaleP-Pulmonale– Indicates right atrial Indicates right atrial
enlargementenlargement– Peaked P-wave in limb leadsPeaked P-wave in limb leads
• Taller than 2.5mm (2 1/2 boxes)Taller than 2.5mm (2 1/2 boxes)
P-WaveP-Wave
• Intra-atrial conduction Intra-atrial conduction delaydelay– In V1In V1– Taller than it is deepTaller than it is deep– Delay in Bacchmann’s Delay in Bacchmann’s
bundlebundle
PR-IntervalPR-Interval
• < 200 ms< 200 ms
• > 120 ms> 120 ms
PR-IntervalPR-Interval
• PR-ElevationPR-Elevation– Usually indicates poor Usually indicates poor
baselinebaseline
• PR-DepressionPR-Depression– May indicate pericarditisMay indicate pericarditis– May indicate atrial May indicate atrial
infarctioninfarction
Short PR-IntervalShort PR-Interval
• Accessory PathwayAccessory Pathway– Bypasses AV nodeBypasses AV node– Predisposes patients to significant re-entry Predisposes patients to significant re-entry
tachycardias. tachycardias.
Accessory PathwayAccessory Pathway
• Wolff-Parkinson-White Syndrome (WPW)Wolff-Parkinson-White Syndrome (WPW)– Bundle of KentBundle of Kent– Short PR-IntervalShort PR-Interval– Delta Wave, Wide QRSDelta Wave, Wide QRS
• Lown-Ganong-Levine Syndrome (LGL)Lown-Ganong-Levine Syndrome (LGL)– James FiberJames Fiber– Short PR-IntervalShort PR-Interval– Normal P-wave, Normal QRSNormal P-wave, Normal QRS
WPWWPW
Bundle of KentBundle of Kent
WPWWPW
• Three conduction patternsThree conduction patterns– Physiological - Normal conduction, no changes may Physiological - Normal conduction, no changes may
be noted on 12-Leadbe noted on 12-Lead– Orthodromic - Signal travels down Kent bundle and Orthodromic - Signal travels down Kent bundle and
physiological pathway. physiological pathway. • Causes shortened PR-Interval & Delta Wave.Causes shortened PR-Interval & Delta Wave.
– Antidromic - From SA Node through Kent bundle to Antidromic - From SA Node through Kent bundle to ventricles then back to atrium via AV junction. ventricles then back to atrium via AV junction.
• Causes very fast wide complex tachycardias. Causes very fast wide complex tachycardias. • Looks like V-tach.Looks like V-tach.
WPWWPW Physiological Physiological
ConductionConduction
WPWWPW Orthodromic Orthodromic
ConductionConduction
WPWWPW
Shortened PR-Interval
Widened QRS
Delta Wave
WPWWPW Antidromic Antidromic
ConductionConduction
WPWWPW
WPWWPW
WPWWPW
WPWWPW
WPWWPW
• Fast, Broad, & Irregular (FBI)Fast, Broad, & Irregular (FBI)– Tachycardic, Wide QRS, Irregular rhythmTachycardic, Wide QRS, Irregular rhythm– Atrial Fibrillation with WPWAtrial Fibrillation with WPW– Atrial Fibrillation with BBBAtrial Fibrillation with BBB
• Always suspect WPW until proven otherwise!Always suspect WPW until proven otherwise!
WPWWPW
Fast, Broad, & IrregularFast, Broad, & Irregular
LGLLGL
Lown-Ganong-Levine Syndrome (LGL)Lown-Ganong-Levine Syndrome (LGL)» James Fiber bypasses the AV node. James Fiber bypasses the AV node. » Shortened PR-Interval.Shortened PR-Interval.
LGLLGL
QuickTime™ and a decompressor
are needed to see this picture.
Shortened PR-IntervalShortened PR-Interval
• The take home message:The take home message:– Recognizing the presence of an accessory Recognizing the presence of an accessory
pathway is much more important than the pathway is much more important than the ability to differentiate between the different ability to differentiate between the different types of accessory pathways. types of accessory pathways.
QRS ComplexQRS Complex
• Height & Morphology Height & Morphology will vary, depending on will vary, depending on the lead.the lead.
• Normal WidthNormal Width– > 0.10 seconds> 0.10 seconds– < 0.12 seconds< 0.12 seconds
QRS ComplexQRS Complex
• Much of our 12-Lead ECG interpretation Much of our 12-Lead ECG interpretation is going to be directly related to the is going to be directly related to the morphology of the QRS complex. morphology of the QRS complex.
• The morphology of the QRS complex The morphology of the QRS complex will assist us in identifying BBBs, V-will assist us in identifying BBBs, V-tach, LVH, RVH, and infarction.tach, LVH, RVH, and infarction.
QRS Complex
• Wide Complex Tachycardia (WCT)– Ventricular Tachycardia
• Josephson’s Sign– Notching of the downslope of S-Wave
• Brugada’s Sign– From behining of QRS to Nadir of S-Wave > 100ms
• QRS > 140ms
• Supraventricular Tachycardia (SVT)– Must have RBBB or LBBB pattern
QRS Complex
Josephson’s Sign
Bundle BranchesBundle Branches
Bundle Branch BlocksBundle Branch Blocks
• Right Bundle Branch Block (RBBB)Right Bundle Branch Block (RBBB)– The single right fascicle is blocked.The single right fascicle is blocked.
• Left Bundle Branch Block (LBBB)Left Bundle Branch Block (LBBB)– Both left fascicles are blocked.Both left fascicles are blocked.
• Non-Specific Intraventricular conduction delay (IVCD)Non-Specific Intraventricular conduction delay (IVCD)– BBB that doesn’t meet RBBB or LBBB criteria.BBB that doesn’t meet RBBB or LBBB criteria.
Bundle Branch BlocksBundle Branch Blocks
• May mimic an MIMay mimic an MI
• The side that is blocked conducts last The side that is blocked conducts last and takes longer.and takes longer.
Bundle Branch BlocksBundle Branch Blocks
• Normal Normal conduction conduction without a block.without a block. 1
3
22
3
4
Mean vector
Cardiac vector
Bundle Branch BlocksBundle Branch Blocks
• With a RBBB, the With a RBBB, the right fascicle is right fascicle is blocked, so the left blocked, so the left ventricle is ventricle is conducted first and conducted first and then the impulse then the impulse returns to the right.returns to the right.
1
2
3
Bundle Branch BlocksBundle Branch Blocks
• With a LBBB, the With a LBBB, the right ventricle is right ventricle is conducted first, conducted first, and the impulse and the impulse travels back to the travels back to the left.left.
1
2
3
Bundle Branch BlocksBundle Branch Blocks
V1
Bundle Branch BlocksBundle Branch Blocks
J-Points
The J-point is the exact point where the QRS ends
V1
Bundle Branch BlocksBundle Branch Blocks
V1
Bundle Branch BlocksBundle Branch Blocks
V1
Bundle Branch BlocksBundle Branch Blocks
V1
Bundle Branch BlocksBundle Branch Blocks
= RBBB
= LBBB
V1
V1
Bundle Branch BlocksBundle Branch Blocks
V1
RBBB
LBBB
Right Bundle Branch BlockRight Bundle Branch Block
• RBBB RBBB morphologiesmorphologies
V1
Right Bundle Branch BlockRight Bundle Branch Block
• To properly differentiate between To properly differentiate between bundle branch blocks, you must also bundle branch blocks, you must also assess leads I and V6. assess leads I and V6.
• A slurred S-wave in leads I and V6 A slurred S-wave in leads I and V6 indicate a RBBB. indicate a RBBB.
Right Bundle Branch BlockRight Bundle Branch Block
I & V6
Right Bundle Branch BlockRight Bundle Branch Block
aVR V4
II aVL V2 V5
III aVF V3
V1
V6
II
Right Bundle Branch BlockRight Bundle Branch Block
Slurred S-Wave I & V6Slurred S-Wave I & V6
Right Bundle Branch BlockRight Bundle Branch Block
+
+
+ A B A
B
Mean vector moves towards positive electrode = positive QRSMean vector moves towards positive electrode = positive QRSMean vector moves away from positive electrode = negative QRSMean vector moves away from positive electrode = negative QRSMean vector is perpendicular to positive electrode = equiphasic QRSMean vector is perpendicular to positive electrode = equiphasic QRS
Right Bundle Branch BlockRight Bundle Branch Block
1
2
3I & V6I & V6
+
Right Bundle Branch BlockRight Bundle Branch Block
Right Bundle Branch BlockRight Bundle Branch Block
Right Bundle Branch BlockRight Bundle Branch Block
Right Bundle Branch BlockRight Bundle Branch Block
Right Bundle Branch BlockRight Bundle Branch Block
Left Bundle Branch BlockLeft Bundle Branch Block
• Duration greater than 0.12 secDuration greater than 0.12 sec
• Broad monomorphic R-wave in I & V6Broad monomorphic R-wave in I & V6
• Terminal S-wave in V1.Terminal S-wave in V1.
Left Bundle Branch BlockLeft Bundle Branch Block
V1V1
Left Bundle Branch BlockLeft Bundle Branch Block
aVR V4
II aVL V2 V5
III aVF V3
II
V6
I V1
Left Bundle Branch BlockLeft Bundle Branch Block
Left Bundle Branch BlockLeft Bundle Branch Block
Left Bundle Branch BlockLeft Bundle Branch Block
Left Bundle Branch BlockLeft Bundle Branch Block
Intraventricular Conduction Intraventricular Conduction DelayDelay
• A Non-specific IVCD is less common A Non-specific IVCD is less common than a RBBB or LBBBthan a RBBB or LBBB
• They are wide, atrial rhythms that They are wide, atrial rhythms that usually look like a left or right BBB in usually look like a left or right BBB in V1, but do not match the criteria in I & V1, but do not match the criteria in I & V6.V6.
Non-Specific IVCDNon-Specific IVCD
aVR V4
II aVL V2 V5
III aVF V3
III V1
V6
Non-Specific IVCD
Non-Specific IVCD
BBB ChartBBB Chart
RBBB LBBB IVCD
V1 TERMINAL
R-WAVE
TERMINAL
S-WAVE
TERMINAL
R/S-WAVE
I & V6 TERMINAL
S-WAVE
TERMINAL
R-WAVE
Anything is possible
Ventricular EnlargementVentricular Enlargement
• Left Ventricular Hypertrophy (LVH)Left Ventricular Hypertrophy (LVH)– The left ventricle is enlargedThe left ventricle is enlarged– Probably due to left-sided heart failureProbably due to left-sided heart failure
• Right Ventricular Hypertrophy (RVH)Right Ventricular Hypertrophy (RVH)– The right ventricle is enlargedThe right ventricle is enlarged– Probably due to right sided heart failureProbably due to right sided heart failure– May be due to pulmonary diseaseMay be due to pulmonary disease
Ventricular EnlargementVentricular Enlargement
• Left Ventricular Hypertrophy (LVH)Left Ventricular Hypertrophy (LVH)– May cause left axis deviationMay cause left axis deviation– May cause a left ventricular strain patternMay cause a left ventricular strain pattern
• Often mimics an anterior MIOften mimics an anterior MI
• Right Ventricular Hypertrophy (RVH)Right Ventricular Hypertrophy (RVH)– May cause right axis deviationMay cause right axis deviation– May cause a right ventrcular strain patternMay cause a right ventrcular strain pattern
• May mimic a inferior or posterior wall MIMay mimic a inferior or posterior wall MI
LVHLVH
RV LV Hypertrophy
Normal LVH
LVHLVH
• LVH CriteriaLVH Criteria– Large QRS complexesLarge QRS complexes
• Deepest S-wave in V1 or V2Deepest S-wave in V1 or V2• Tallest R-wave in V5 or V6Tallest R-wave in V5 or V6
– Add them togetherAdd them together» If the result is > 25mm = LVHIf the result is > 25mm = LVH
• Most texts may read: Most texts may read: – S-wave (V1/V2) + R-wave(V5/V6) > 35mmS-wave (V1/V2) + R-wave(V5/V6) > 35mm– However, tall R-waves and deep S-waves may However, tall R-waves and deep S-waves may
be cut off by the monitor. be cut off by the monitor. – Use the 25mm criteria and examine for “strain”Use the 25mm criteria and examine for “strain”
LVHLVH
V1 or V2V1 or V2
S R
V5 or V6
+
LVHLVH
Lets take a look at an exampleLets take a look at an example
LVHLVH
Lets take a look at an exampleLets take a look at an example
LVHLVH
Lets take a look at an exampleLets take a look at an example
LVHLVH
Lets take a look at an exampleLets take a look at an example
14mm
LVHLVH
Lets take a look at an exampleLets take a look at an example
14mm
LVHLVH
14 + 15 = 29mm14 + 15 = 29mm
14mm 15mm
LVHLVH
• Since our total was 29mm, and a total of Since our total was 29mm, and a total of > 25mm meets LVH criteria, we can > 25mm meets LVH criteria, we can assume that this ECG is that of a assume that this ECG is that of a patient with LVH.patient with LVH.
*LVH may look a lot like a narrow LBBB.*LVH may look a lot like a narrow LBBB.
LVHLVH
• A wave that is A wave that is too tall or deep too tall or deep may be cut off may be cut off by the monitor by the monitor
• This is a This is a indicator of indicator of hypertrophyhypertrophy
LVHLVH
• A wave that is too tall A wave that is too tall or deep may be cut or deep may be cut off by the monitor off by the monitor
• This is a indicator of This is a indicator of hypertrophyhypertrophy
LVHLVH
Additional LVH CriteriaAdditional LVH Criteria
Any precordial lead
> 45mm
aVL > 11mm
Lead I > 12mm
aVF > 20mm
Ventricular LeadsVentricular Leads
Right Ventricular Left Ventricular
RVHRVH
• Right Ventricular HypertrophyRight Ventricular Hypertrophy– Criteria = R:S ration > 1 in V1/V2Criteria = R:S ration > 1 in V1/V2
• This means that the R-wave is bigger than the This means that the R-wave is bigger than the S-wave in V1 or V2.S-wave in V1 or V2.
• The QRS complex should be narrowThe QRS complex should be narrow• P-Pulmonale may be present.P-Pulmonale may be present.• Right axis deviation is common.Right axis deviation is common.
RVHRVHV1 or V2
R
S
V1/V2: R > S = RVH•QRS < 120ms (0.12 sec)
= 9mm
= 6mm
RVHRVH
RVHRVH
Let’s take a look…Let’s take a look…
RVHRVH
Let’s take a look…Let’s take a look…
QRS ComplexQRS Complex
• Low VoltageLow Voltage– Chronic Cor PulmonaleChronic Cor Pulmonale
• Progressive lung disease, leading to right-sided heart Progressive lung disease, leading to right-sided heart failure.failure.
– Pericardial EffusionPericardial Effusion• Fluid in the pericardial sac.Fluid in the pericardial sac.
– Excessive ObesityExcessive Obesity
T WaveT Wave
• Should not be Should not be symmetrical.symmetrical.
• Should be upright in Should be upright in every lead but aVR.every lead but aVR.
• Height should Height should correlate with QRS.correlate with QRS.
• Should have a dull Should have a dull peak.peak.
Symmetrical T-WaveSymmetrical T-Wave
AsymmetricalNormal
SymmetricalAbnormal
HyperkalemiaHyperkalemia
• Hyperkalemia = High Potassium LevelHyperkalemia = High Potassium Level– Peaked T-WavesPeaked T-Waves
• May mimic an acute MIMay mimic an acute MI
– Sine WavesSine Waves• Sign of lethally high potassium levelSign of lethally high potassium level
Sine Wave
Peaked T-Wave
HyperkalemiaHyperkalemia
HyperkalemiaHyperkalemia
Hyperkalemia
T-Wave DiscordanceT-Wave Discordance
• Discordance means opposite.Discordance means opposite.– T-Wave discordance means that the T-T-Wave discordance means that the T-
Wave is deflected in the opposite direction Wave is deflected in the opposite direction as the terminal (last) wave of the QRS.as the terminal (last) wave of the QRS.
– T-Wave discordance is normal in every T-Wave discordance is normal in every lead with Left or Right BBBs.lead with Left or Right BBBs.
T-Wave DiscordanceT-Wave Discordance
Digitalis EffectDigitalis Effect
• Shortened QT intervalShortened QT interval• Characteristic down-sloping ST depressionCharacteristic down-sloping ST depression• DysrhythmiasDysrhythmias
– ventricular / atrial premature beatsventricular / atrial premature beats– paroxysmal atrial tachycardia with variable AV blockparoxysmal atrial tachycardia with variable AV block– ventricular tachycardia and fibrillationventricular tachycardia and fibrillation– many othersmany others
Digitalis EffectDigitalis Effect
QT-IntervalQT-Interval
Normal QTc Normal QTc
< 460 ms< 460 ms
QT-IntervalQT-Interval
Measures the time from when depolarization Measures the time from when depolarization starts to the end of repolarization.starts to the end of repolarization.
QTc = RR
QT
QT-IntervalQT-Interval
Long QT SyndromeLong QT Syndrome
• QTc > 460msQTc > 460ms– CongenitalCongenital
• Major contributor to sudden unexplained death Major contributor to sudden unexplained death in children and young adults.in children and young adults.
– Drug inducedDrug induced• Caused by many arrhythmia medicationsCaused by many arrhythmia medications
U-WaveU-Wave
• Usually not Usually not visible.visible.
• Should not be Should not be prominent.prominent.
• Should never Should never be bigger than be bigger than T-waveT-wave
Osborn Waves
• Sometimes called “J-Waves”
• Indicates HYPOTHERMIA
• May be associated with bradycardia
• Extra wave at the J-Point of the QRS-complex.
Osborn Waves
Osborn Waves
Lesson 3
• This concludes lesson 3
• Practice examining different intervals & morphologies.