8 morphology of qrs
TRANSCRIPT
12-Lead Electrocardiographya comprehensive course
Adam Thompson, EMT-P, A.S.
Morphologi
es(The
“QRS”)
QRS Complex
The morphology of the QRS complex will assist us in identifying BBBs, V-tach, LVH, RVH, and infarction.
QRS Complex
• Height & Morphology will vary, depending on the lead.
• Normal Width– > 0.10 seconds– < 0.12 seconds
Bundle Branches
Bundle Branch Blocks
• Right Bundle Branch Block (RBBB)– The single right fascicle is blocked.
• Left Bundle Branch Block (LBBB)– Both left fascicles are blocked.
• Non-Specific Intraventricular conduction delay (IVCD)– BBB that doesn’t meet RBBB or LBBB criteria.
Bundle Branch Blocks
• May mimic an MI• The side that is blocked conducts last and
takes longer.
Bundle Branch Blocks
• Normal conduction without a block. 1
32
2
3
4
Mean vector
Cardiac vector
Right Bundle Branch Block
+
+
+ A B A
B
Mean vector moves towards positive electrode = positive QRSMean vector moves away from positive electrode = negative QRSMean vector is perpendicular to positive electrode = equiphasic QRS
Bundle Branch Blocks
• With a RBBB, the right fascicle is blocked, so the left ventricle is conducted first and then the impulse returns to the right.
1
2
3
Bundle Branch Blocks
• With a LBBB, the right ventricle is conducted first, and the impulse travels back to the left.
1
2
3
Bundle Branch Blocks
V1
Bundle Branch Blocks
J-Points
The J-point is the exact point where the QRS ends
V1
Bundle Branch Blocks
V1
Bundle Branch Blocks
V1
Bundle Branch Blocks
V1
Bundle Branch Blocks
= RBBB
= LBBB
V1
V1
Bundle Branch Blocks
V1
RBBB
LBBB
Right Bundle Branch Block
• RBBB morphologies
V1
Right Bundle Branch Block
Left Bundle Branch Block
V1
Left Bundle Branch Block
Intraventricular Conduction Delay
• A Non-specific IVCD is less common than a RBBB or LBBB
• They are wide, atrial rhythms that usually look like a left or right BBB in V1, but do not match the criteria in I & V6.
Ventricular Enlargement
• Left Ventricular Hypertrophy (LVH)– The left ventricle is enlarged– Probably due to left-sided heart failure
• Right Ventricular Hypertrophy (RVH)– The right ventricle is enlarged– Probably due to right sided heart failure– May be due to pulmonary disease
Ventricular Enlargement
• Left Ventricular Hypertrophy (LVH)– May cause left axis deviation– May cause a left ventricular strain pattern
• Often mimics an anterior MI
• Right Ventricular Hypertrophy (RVH)– May cause right axis deviation– May cause a right ventrcular strain pattern
• May mimic a inferior or posterior wall MI
LVH
RV LV Hypertrophy
Normal LVH
LVH
LVH Criteria– Large QRS complexes
• Deepest S-wave in V1 or V2• Tallest R-wave in V5 or V6
– Add them together» If the result is > 25mm = LVH
LVH
V1 or V2
S R
V5 or V6
+
LVH
Lets take a look at an example
LVH
Lets take a look at an example
LVH
Lets take a look at an example
LVH
Lets take a look at an example
14mm
LVH
Lets take a look at an example
14mm
LVH
14 + 15 = 29mm
14mm 15mm
LVH
• Since our total was 29mm, and a total of > 25mm meets LVH criteria, we can assume that this ECG is that of a patient with LVH.
*LVH may look a lot like a narrow LBBB.
LVH
• A wave that is too tall or deep may be cut off by the monitor
• This is a indicator of hypertrophy
LVH
• A wave that is too tall or deep may be cut off by the monitor
• This is a indicator of hypertrophy
LVH
Additional LVH Criteria
Any precordial lead
> 45mm
aVL > 11mm
Lead I > 12mm
aVF > 20mm
Ventricular Leads
Right Ventricular Left Ventricular
RVH
• Right Ventricular Hypertrophy– Criteria = R:S ration > 1 in V1/V2
• This means that the R-wave is bigger than the S-wave in V1 or V2.
• The QRS complex should be narrow• P-Pulmonale may be present.• Right axis deviation is common.
RVH
V1 or V2
R
S
V1/V2: R > S = RVH• QRS < 120ms (0.12 sec)
= 9mm
= 6mm
RVH
RVH
Let’s take a look…
RVH
Let’s take a look…
PathologiesFrontal Plane Axis Precordial Axis
ERAD-90 to 180
Right Axis Deviation90 to 180
Pathological Left Axis Deviation
-30 to -90
Early TransitionCounterclockwise
Rotation
Late TransitionClockwise Rotation
• Ventricular Rhythm• Paced Rhythm• Dextrocardia• Electrolyte derangement
• May be normal• LPFB• Pulmonary disease• RVH• RBBB• WPW• Dextrocardia•Venrticular Rhythm
• Pregnancy• LAFB• WPW• Pulmonary disease• LBBB• Hyperkalemia• Q-waves, MI
• Posterior wall infarction• RVH• RBBB• WPW
• Sometimes Normal, especially in women• Anterior MI• LVH• LAFB• LBBB• Lung Disease
QRS Complex
Low Voltage– Chronic Cor Pulmonale
• Progressive lung disease, leading to right-sided heart failure.– Pericardial Effusion
• Fluid in the pericardial sac.– Excessive Obesity
END
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