Atrial and Ventricular Enlargement

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Atrial and Ventricular Enlargement

• Chapter 6

2
Web Site Instruction

• http//www.madsci.com/manu/ekg_hypr.htm
• http//library.med.utah.edu/kw/ecg/ecg_outline/Les
  son7/index.html
• http//library.med.utah.edu/kw/ecg/ecg_outline/Les
  son8/index.html

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Cardiac Enlargement

• Dilation
• stretched
• e.g. congestive heart failure
• Hypertrophy
• increase size of heart muscle fibers
• e.g. aortic stenosis

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Cardiac Enlargement

• Increase amount/area of cardiac tissue
• How would this affect depolarization?
• How could that affect an ECG?

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Right Atrial Abnormality

• Overload of the right atria
• dilation
• hypertrophy
• also known as P pulmonale
• How would this change the P wave?

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Right Atrial Abnormality
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Right Atrial Abnormality

• Normal P wave is less than 2.5 mm tall and 0.12
  seconds wide.
• With right atrial hypertrophy, P waves are
  typically taller than 2.5 mm but not wider than
  0.12 sec.

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Right Atrial Abnormality Criteria

• Tall P waves in lead II
• (or III, aVF and sometimes V1)

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Right Atrial Abnormality

• Causes
• Pulmonary disease
• Congenital heart disease

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Left Atrial Abnormality

• Also known as P mitrale
• Left atria normally depolarizes after the right
  atria.
• How would this affect the P wave?
• wider left atrial enlargement should prolong the
  P wave gt 0.12 sec.

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Left Atrial Abnormality
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Left Atrial Abnormality

• II wide P wave
• V1 negative P wave is 1 box wide, 1 box deep

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Atrial Enlargement
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Left Atrial Abnormality

• Lead II (and I) show wide P waves
• (second hump due to delayed depolarization of the
  left atrium)
• (P mitrale mitral valve disease)
• V1 may show a bi-phasic P wave
• 1 box wide, 1 box deep
• (biphasic since right atria is anterior to the
  left atria)

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Left Atrial Abnormality

• Causes
• Valve disease (mitral and aortic)
• Hypertensive heart disease
• Cardiomyopathies
• Coronary artery disease

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Ventricular Hypertrophy
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12 Leads
Frontal Plane
Transverse Plane
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Normal QRS
V6?
V6?
V1?
V1?
Fig. 4-6
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Normal QRS
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Right Ventricular Hypertrophy

• What do you think will happen to the ECG with
  ventricular hypertrophy?

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Right Ventricular Hypertrophy

• Consider right ventricular hypertrophy and V1
• How would V1 be different?

Normal
Hypertrophy
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Right Ventricular Hypertrophy
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Right Ventricular Hypertrophy Criteria

1. In V1, R wave is greater than the S wave - or -
   R in V1 greater than 7 mm
2. Right axis deviation
3. In V1, T wave inversion (reason unknown)
4. S waves in V5 and V6

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Right Ventricular Hypertrophy

• Causes of RVH
• pulmonary disease
• congenital heart disease
• (Emphysema may mask signs of RVH)
• Posterior wall MI may also show tall R waves in V1

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Fig 6.8
R wave and T wave in V1?
What about the axis?
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ECG Interpretation

1. Rate
2. RR interval
3. Heart rate
4. Rhythm
5. PP interval
6. P wave
7. width, height, shape, etc.
8. PR interval
9. QRS
10. width (and height)
11. axis
12. R wave progression
13. abnormal Q waves
14. QT interval
15. ST segment
16. T waves
17. U waves

See Chapter 22
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Fig 6.9
R wave in V1. P waves in II, III, V1
T wave inversion PR interval
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Left Ventricular Hypertrophy

• With LVH, the electrical balance is tipped even
  further to the left.
• Tall R waves in the left chest leads
• Predominate S waves in the right chest leads

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Left Ventricular Hypertrophy
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Left Ventricular Hypertrophy Criteria

• Sokolow-Lyon Voltage Criteria
• If S wave in V1 R wave in V5 or V6 35 mm (
  50 for under 35 yrs of age)
• R wave gt 11 mm in aVL or I...
• Also
• LVH is more likely with a strain pattern or ST
  segment changes
• Left axis deviation
• Left atrial abnormality

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Left Ventricular Hypertrophy

• Causes
• Hypertension
• Aortic stenosis
• not always pathological
• Risks of LVH
• congestive heart failure
• arrhythmias

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Left Ventricular Hypertrophy

• High voltage can be seen in normal people,
  especially athletes
• With hypertrophy in both ventricles, the ECG will
  show more evidence of LVH

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ST strain patterns
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LVH with ST strain pattern and LAE
Fig 6.10
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LVH (in 20 yr old) without ST strain or LAE
Fig 6.11
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Practice
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RVH
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Left atrial enlargement
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Left ventricular hypertrophy (S wave V2 plus R
wave of V5 greater than 35mm) and left atrial
enlargement (II and V1).
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LVH
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Right atrial enlargement
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LVH
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Right ventricular hypertrophy and right atrial
enlargement.
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RVH
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Right axis deviation (predominant negative QRS in
leads I and aVl) of QRS complex and qR pattern in
V1 suggests severe right ventricular hypertrophy.
Sharp P waves in inferior leads and V1 indicate
right atrial overload. T wave inersion in
inferior and anterior leads are secondary to
right ventricular hypertrophy.
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Tall R waves in V4 and V5 with down sloping ST
segment depression and T wave inversion are
suggestive of left ventricular hypertrophy (LVH)
with strain pattern. LVH with strain pattern
usually occurs in pressure overload of the left
ventricle as in systemic hypertension or aortic
stenosis. Similar pattern may also occur in long
standing severe aortic regurgitation, though the
usual pattern in aortic regurgitation is left
ventricular volume overload. Negative P waves in
lead V1 is indicative of left atrial overload.
Shallow T wave inversions are seen in inferior
leads. Two supra ventricular ectopic beats are
also seen in the rhythm strip. They are
characterized by their premature nature, a P wave
of different morphology preceding the QRS (in
this case merging with the T wave of the previous
beat), narrow QRS complex and an incomplete
compensatory pause.
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Right atrial overload (P pulmonale) and right
ventricular hypertrophy. Right atrial overload
(enlargement) is manifest as tall sharp P waves
in lead II and V1. The cut off values are P wave
amplitude more than 0.25 mV in lead II and 0.1 mV
or more in V1. Dominant R waves in V1 and deep S
waves in V6 indicate right ventricular
hypertrophy (RVH). Sokolow-Lyon for RVH criteria
mentions that R wave in V1 S wave in V5/V6
should be 1.1 mV or more. There is also a
clockwise rotation in the QRS pattern between V1
to V6. QRS axis is around 120 degrees (aVR
biphasic and lead III showing tallest QRS
complex). Right axis deviation is also due to
right ventricular hypertrophy. T wave inversion
in inferior leads and V1 could be due to right
ventricular hypertrophy itself. RVH in this case
is type A with dominant R in V1 and deep S in V6.
This type is seen in pulmonary stenosis. Type B
RVH shows dominant R waves in V1 without deep S
in V6. Deep S in V6 without dominant R in V1 seen
in chronic obstructive lung disease with
cor-pulmonale is called type C RVH. (Strictly
speaking the types are classified depending upon
vector cardiographic features and not based on
scalar ECG)