Understanding the Echocardiography Report

Colin Royse
University of Melbourne
Melbourne

Purpose of Study

A standard echocardiography report is often very confusing or confronting to anaesthetists as it is full of numbers and technical jargon. The purpose of this presentation is to decipher some of the jargon and to give you an approach to working through an echocardiography report.

Method
NA

Result
NA

Conclusion

Step 1. Understand that the numbers are there for quantification, but the text is there for interpretation. If you don't have much time, go straight to the comment or conclusion section to get a description of the overall or most important pathology. After this, work through each component of the heart.

Step 2. The left ventricle:

1. Size: differentiate small, from normal, from dilated as these indicate different pathology
2. Systolic function: you are interested in whether the global function is hyperdynamic, normal, or reduced. Global function is assessed using an estimation of ejection fraction. FS stands for fractional shortening and is calculated using a one dimensional measurement which is converted into ejection fraction (normal fractional shortening is > 28%, and normal ejection fraction is 50-65%). Look for comments about regional wall motion abnormalities (or systolic wall motion abnormalities-they are the same) as these are indicators of previous infarction, or could be consistent with current ischaemia if the clinical scenario fits it.
3. Diastolic function: this relates to how stiff the heart is. There are lots of numbers devoted to try and quantify diastolic function (such as mitral valve inflow velocities, pulmonary vein velocities, or tissue Doppler velocites). There are many problems with current methods of estimating diastolic dysfunction, but you want to look for the category normal/mild versus moderate/severe. If you see terms such as "pseudo-normal or restrictive" then assume that there is significant diastolic dysfunction, versus "normal or impaired relaxation" which suggests diastolic function is normal/mild. Look for sneaky ways of trying to describe elevated left atrial pressure such as E/Ea > 15. Hopefully the reporting Dr will describe an elevated left atrial pressure if there is one. This is an indication of significant diastolic dysfunction.
4. Left ventricular hypertrophy: this is calculated from the thickness of the walls and the dimension of the ventricle, but beware of people with moderate or severe left ventricular hypertrophy, as they will frequently have significant diastolic dysfunction and may have a very steep Starling's curve.

Step 3. The right ventricle:

1. Quantification of right ventricular size and function is not as easy to quantify as the left ventricle, and so you will generally see a descriptive comment such as normal size or dilated, and normal or reduced function. As a rule of thumb, the right ventricle should be approximately two thirds the size of the left, and if they become equal in size, this indicates significant right ventricular pathology.
2. Pulmonary hypertension is quantified using Doppler if there is tricuspid regurgitation present. The right ventricular systolic pressure (RVSP) correlates with peak systolic pulmonary artery pressure and is a reasonable guide to the presence or absence of pulmonary hypertension. If you see sneaky words such as "D-shaped septum" this refers to the shape of the interventricular septum being flattened and is an indication of severe right ventricular pressure or volume overload. These are patients to be very cautious with!

Step 4. Atria

1. Atrial size alone is a soft indicator of ventricular pathology. The atrium is the "window" to the left ventricle, and changes in the left ventricular cavity are reflected in the atrium. You're more likely to have diastolic dysfunction if the atrium is dilated, but other conditions can cause it - so it is not absolute. The reporter may observe the shape and movement of the interatrial septum which gives more information concerning the left atrial pressure state.

Step 5. Valves:

1. General approach: firstly, the valves most likely to influence anaesthetic practice are the aortic and mitral valves, rather than pulmonary or tricuspid. Look at these valves first and then look at tricuspid and pulmonary. In general, you need to differentiate whether the stenosis or regurgitation falls into the nil/mild or moderate/severe categories. Most reports actually makes this easy for you by having a table categorising the severity of the lesions.
2. Aortic valve: there are a number of ways of calculating aortic valve area or the degree of stenosis, but when considering the moderate/severe category, be concerned if you see aortic valve area <0.9cm2, peak gradient greater than 50 mmHg, or mean gradient > 30mmHg. Moderate aortic stenosis will generally not present problems during anaesthesia, whereas severe aortic stenosis will frequently do so. The point is, a moderate aortic stenosis could be underestimated by the echocardiography report and it is wise to treat a moderate as potentially more severe when anaesthetising your patients. In general, the regurgitatant lesions are less dramatic in effects than the stenotic lesions when patients are anaesthetised, however moderate/severe aortic regurgitation will compromise cardiac output.
3. Mitral valve: again, there is no perfect way of measuring mitral valve stenosis, but if you see the mitral valve area <1.0 cm2, then there is severe stenosis. Moderate/severe mitral regurgitation will compromise forward cardiac output and could compromise patient care. If you see "papillary muscle rupture", this is usually in the setting of acute myocardial infarction and carries very high mortality.
4. Tricuspid valve: tricuspid stenosis is very rare and typically of a rheumatic origin. Tricuspid regurgitation is common, and tends to cause less haemodynamic compromise than aortic or mitral lesions. The important point to remember, is that severe tricuspid regurgitation is often caused by annular dilatation, which is in response to right ventricular pressure or volume overload. The key here is if severe tricuspid regurgitation is reported, look for comments in the echocardiography report for right ventricular pathology.
5. Pulmonary valve: pulmonary valve stenosis is very rare, and so is moderate/severe regurgitation. These are typically of the destructive origin (such as endocarditis), rheumatic or congenital. Both conditions will cause significant problems with anaesthesia, but given the rare nature of them he would be advised to seek expert opinion as to the cause and consequence of the lesion.

Step 6. The extras!

Extra structures include the thoracic aorta, pericardium, pulmonary artery, and a host of congenital lesions. The congenital lesions are really beyond the scope of this tutorial and expert advice should be sought. The most important "extra" is pericardial effusion, as this could cause tamponade. You can have a large pericardial effusion without actual tamponade, but the larger the effusion, the more likely it will press on the heart. if you see terms such as " respiratory variation in tricuspid inflow >40cm/sec or mitral inflow >25cm/sec), then tamponade is likely.

Step 7. If in doubt seek expert advice!

Time of Presentation
1030