Left Ventricular Systolic Function

Published on 06/02/2015 by admin

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Last modified 22/04/2025

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Left Ventricular Systolic Function

Eric W. Nelson

For some reason there is a lot of focus on the left ventricle and its evaluation on TEE, both in the operating room and on the boards. This most likely has to do with the fact that it’s pumping blood to the entire body, thus keeping you alive. The easiest way to start your evaluation of the left ventricle is to know what a normal left ventricle looks like.

The shape of the LV should look somewhat like a football. If you drop a TEE probe in someone and the heart is closer to a basketball than a football, something is wrong.

So, now you know how to eyeball the heart and tell grossly if it’s normal or not, but what about an actual measurement? LV function is typically measured numerically by the ejection fraction (EF). That is, how much blood that goes into the LV goes out through the aorta?

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EF can be calculated by measuring the fractional area of change (FAC) of the left ventricle. A true long- or short-axis cross section is required being careful not to foreshorten. Foreshortening is a term commonly used by echocardiographers to describe the heart when it is compressed because of the viewpoint taken. With modern TEE machines all you have to do is outline the end-diastolic area and the end-systolic area and the machine will crunch the numbers.

FAC = (end-diastolic area – end-systolic area)/end-diastolic area

You can also estimate EF via the eyeball method, which is what most people do. On the test you should be able to look at an image and determine the difference between an EF of 25% and 55%. Which is pretty easy!

One thing to keep in mind whether using the eyeball method or doing an actual measurement is don’t jump to conclusions based on one view. A single slice may look great, but remember it’s only part of the heart and another part may not look so good. Also, if you are foreshortening or not getting a “true” cut of the LV your read is going to be off. Make sure you eyeball the LV with multiple omniplane angles and also in both the transgastric and midesophageal views.

Abnormal LV Systolic Function

Naturally, the first thing that comes to mind is ischemia…if this wasn’t your first thought you may want to retake your boards. There are also a lot of other things that may cause abnormal LV function.

Cardiomyopathies

Hypertrophic

There are four different types of hypertrophic cardiomyopathies, although the most famous is septal hypertrophy leading to subaortic stenosis or “hypertrophic obstructive cardiomyopathy”, which all the cool kids just call HOCM (pronounced hokum).

HOCM is an inherited cardiomyopathy. It is autosomal dominant with limited penetrance, unless of course you are the patient then it is a very penetrating diagnosis!

With hypertrophic cardiomyopathies systolic function typically is not the problem, rather the heart has a hard time relaxing, like that one attending we’ve all had with the vein in his forehead that seems to keep growing and may pop at any minute!

An important point about HOCM is the picture you see on TEE. Some people call this the “dagger sign”. When a continuous wave Doppler is placed across the left ventricular outflow tract, or LVOT, and the AV the outflow pattern will resemble a dagger rather than the nice rounded appearance of someone without this problem. This is secondary to the ventricle being so empty at the end of systole and the septum being so huge an obstruction actually occurs.

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Keep in mind that patients with HOCM are also more prone to SAM or systolic anterior motion of the mitral valve. Since the outflow tract is already narrow, it’s easy for the anterior leaflet to get sucked in and impede flow.

The definitive answer to relieving HOCM is surgical resection of the septum. TEE plays an important role here in order to determine preop if the surgery is necessary and postop if there was enough septum resected, not enough, or too much. If not enough was taken the obstruction will remain, but if the surgeon got a little greedy the patient may end up with a VSD. Also remember that there are conduction fibers running through the septum. It’s not uncommon to have a heart block after this type of surgery.

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Medical management of HOCM involves keeping the heart full; remember that the obstruction occurs when the heart is empty; and also decreasing contractility.

Restrictive

Sometimes the only way to tell the difference between a hypertrophic and restrictive cardiomyopathy is by looking at the posterior basal wall of the heart. This is best appreciated in the transgastric short-axis views. Remember, in hypertrophic cardiomyopathies the posterior basal wall is spared, but in restrictive cardiomyopathies it is not. Oh yeah, don’t forget that a good history and physical can also help determine the type of cardiomyopathy as well.

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Alright, we’ve determined that we have a restrictive cardiomyopathy, but where’d it come from? Well, the list is long and distinguished. There are a lot of things that can “sneak” into the myocardium and cause restriction:

Like hypertrophic cardiomyopathies, restrictive cardiomyopathies mainly present a problem in diastole that is the heart does not relax well enough to accept blood. Remember to go over the various diastolic E/A patterns and pulmonary venous flow because these do show up on the test!

Patients with restrictive heart disease are also prone to thrombus formation even without a wall motion abnormality. Thrombi are typically found in the apex. Remember, the apex of the heart is best visualized in the mid-esophageal 2-chamber view and the mid-esophageal 4-chamber view. Thrombi may also form under the posterior mitral valve leaflet, which may lead to a bit of mitral regurgitation.

Questions

1. Which wall is spared in hypertrophic cardiomyopathy?

2. Which of the following may cause cardiomyopathy?

3. Where is the most likely place to find thrombus in the LV?

4. Treatment for HOCM includes all of the following except:

5. What causes hemodynamic compromise in patients with HOCM?

6. Which of the following causes restrictive cardiomyopathy?

7. Which of the following patients are prone to LV thrombus formation:

8. A problem in which of the following spaces may affect LV systolic function?

9. True or false: It is possible to evaluate the ejection fraction of the heart by one view on TEE

10. Which view is the best to evaluate HOCM

Answers

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