Chamber Hypertrophy and Enlargment

Author(s)	J.S.S.G. de Jong
Moderator	J.S.S.G. de jong
Supervisor
some notes about authorship

In hypertrophy the heart muscle becomes thicker. This can have different causes. Left ventricular hypertrophy results from an increase in left ventricular workload, e.g., during hypertension or aortic valve stenosis. Right ventricular hypertrophy results from an increase in right ventricular workload, e.g., emphysema or pulmonary embolization. These causes are fundamentally different from hypertrophic obstructive cardiomyopathy (HCM), which is a congenital misalignment of cardiomyocytes, resulting in hypertrophy.

Left and right ventricular hypertrophy can be distinguished on the ECG:

Left ventricular hypertrophy

LVH. R in V5 is 26mm, S in V1 in 15mm. The sum is 41 mm which is more than 35 mm and therefore LVH is present according to the Sokolow-Lyon criteria.

As the left ventricular wall becomes thicker, the QRS complexes become larger. This is especially true for leads V1-V6. The S wave in V1 is deep, the R wave in V4 is high. Often some ST depression can be seen in leads V5-V6, which is in this setting is called a 'strain pattern'.

To diagnose left ventricular hypertrhophy on the ECG one of the following criteria should be met: The Sokolow-Lyon criterium[1]), this is most often used:

• R in V5 or V6 + S in V1 >35 mm.

This criterium is not reliable below age 40 years.[2] In 10-29 year olds, the 99th percentile for SV1+RV5 is 53mm. In 20-39 year olds: 32% have SV2+RV5 > 35 mm.[3] Correlation between LVH on ECG and echocardiography is low with ECG having a sensitivity of 27% and specicity of 88% for echocardiographically measured LVH[4][5]. Moreover, both are independent estimators of worse prognosis.[6].

The Cornell-criterium has different values in men and women:

• R in aVL and S in V3 >28 mm in men
• R in aVL and S in V3 >20 mm in women

This is a better predicting criterium than the Sokolow-Lyon criterium, but less easy to remember, and therefore less often used.[7][8]

In the Romhilt-Estes Score LVH is likely with 4 or more points. LVH is present with 5 or more points: Romhilt-Estes point score system ("diagnostic" >5 points; "probable" 4 points):[9]

Romhilt has reviewed ECG LVH criteria and gives an overview of the many LVH scoring systems. [10] Left ventricular hypertrophy has prognostic consequences as has been found in several studies.[7][8]

Example

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  ECG of patient with left ventricular hypertrophy according to the Sokolow-Lyon criteria

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  Another example of extreme left ventricular hypertrophy in a patient with severe aortic valve stenosis.

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  ECG of a patient with LVH and subendocardial ischemia leading to positive cardiovascular markers in blood testing.

Right ventricular hypertrophy

An example of right ventricular hypertrophy (and right atrial enlargement) in a patient with chronic pulmonary hypertension due to peripheral embolisation.

Another example fo right ventricular hypertrophy.

Right ventricular hypertrophy, the R wave is greater than the S wave in V1

Right ventricular hypertrophy occurs mainly in lung disease or in congenital heart disease. The ECG shows a negative QRS complex in I (and thus a right heart axis) and a positive QRS complex in V1.

• QRS duration < 120ms
• Right heart axis (> 110 degrees)
• Dominant R wave:
  • R/S ratio in V1 or V3R > 1, or R/S ratio in V5 or V6 <= 1
  • R wave in V1 >= 7 mm
  • R wave in V1 + S wave in V5 or V6 > 10.5 mm
  • rSR= in V1 with R'= > 10 mm
  • qR complex in V1
• Secondary ST-T changes in right precordial leads
• Right atrial abnormality
• Onset of intrinsicoid deflection in V1 between 0.035 and 0.055 s

Left atrial enlargement

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  Left atrial enlargement

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  Left atrial enlargement with ECG.

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  Left atrial enlargement as seen in lead V1.

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  Left atrial enlargement as seen on a 12 lead ECG

Criteria for left atrial voor left atrial enlargement. Either

P wave with a broad (>0.04 sec or 1 small square) and deeply negative (>1 mm) terminal part in V1

P wave duration >0.12 sec in leads I and / or II

Left atrial enlargement is often seen in mitral valve insufficiency, resulting in back flow of blood from the left ventricle to the left atrium and subsequent increased local pressure.

Right atrial enlargement

• 

  Right atrial enlargement

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  Right atrial enlargement

Right atrial enlargement is defined as either

P >2.5 mm in II / III and / or aVF

P >1.5 mm in V1.

Right atrial enlargement can result from increased pressure in the pulmonary artery, e.g. after pulmonary embolization. A positive part of the biphasic p-wave in lead V1 larger than the negative part indicates right atrial enlargement. The width of the p wave does not change.

Biatrial enlargement

Biatrial enlargement

Biphasic p wave in V1 of more than 0.04 sec duration. The positive initial part is > 1.5mm and the negative terminal part > 1mm

In biatrial enlargement the ECG shows signs of both left and right atrial enlargement. In V1 the p wave has large peaks first in a positive and later in a negative direction.

References

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1. Sokolow M, Lyon TP: The ventricular complex in left ventricular hypertrophy as obtained by unipolar precordial and limb leads. Am Heart J 37: 161, 1949

3. ISBN=1437711022