Transthoracic echocardiogram: ejection fraction, mass and left ventricular geometry in the report

The transthoracic echocardiogram report is, in large part, a report of numbers. And numbers only help when they come with the method, the reference and the interpretation. "EF 55%" without saying how it was measured, or "ventricular hypertrophy" without the indexed mass, forces the cardiologist to redo the calculation or trust the adjective.

This text gathers the left ventricular and left atrial measurements that appear most in the report, with the references from the joint recommendations of the American Society of Echocardiography and the European Association of Cardiovascular Imaging (ASE/EACVI).

Ejection fraction: the method matters

The recommended method is biplane Simpson (method of disks), from the diastolic and systolic volumes in the apical 4- and 2-chamber views. The Teichholz method, based on linear measurements, assumes a geometry that the ventricle with a segmental abnormality does not have, and should not be used in these cases. The report should state which method was used.

Left ventricular ejection fraction references (ASE/EACVI):

• Normal: 52% or more in men and 54% or more in women.
• Mild dysfunction: 41% to 51% in men and 41% to 53% in women.
• Moderate dysfunction: 30% to 40%.
• Severe dysfunction: below 30%.

When there is a segmental contractility abnormality, it should be described by segment, in the 17-segment model, and not summarized in the ejection fraction.

Left ventricular mass

Mass is calculated by the linear method (the ASE cubed formula, from the diastolic diameter and the septal and posterior wall thicknesses) and indexed to body surface area. The upper limits of normal are 115 g/m² in men and 95 g/m² in women. Without indexing, the same absolute value can be normal in a large patient and hypertrophy in a small one.

Relative wall thickness and the four geometries

Relative wall thickness (RWT) is calculated as twice the posterior wall thickness divided by the diastolic diameter. The cutoff is 0.42. Crossing RWT with indexed mass, the ventricle is classified into four geometries:

• Normal: normal mass and RWT up to 0.42.
• Concentric remodeling: normal mass and RWT above 0.42.
• Concentric hypertrophy: increased mass and RWT above 0.42.
• Eccentric hypertrophy: increased mass and RWT up to 0.42.

Geometry has its own clinical meaning, especially in hypertension, and merits a line in the report even when the ejection fraction is normal.

Left atrium: volume, not diameter

The anteroposterior diameter of the left atrium underestimates enlargement, because the atrium grows asymmetrically. The recommended measurement is the indexed volume to body surface area, by the biplane method. The upper limit of normal is 34 mL/m². Increased atrial volume is also one of the criteria for assessing diastolic function.

Diastolic function in one sentence

In preserved ejection fraction, the 2016 recommendations use four variables: e' velocity (septal and lateral), average E/e' ratio above 14, tricuspid regurgitation velocity above 2.8 m/s and indexed left atrial volume above 34 mL/m². More than half of the variables abnormal indicates diastolic dysfunction; fewer than half, normal function; exactly half, an indeterminate result. The report should state what the conclusion was and with what data.

Common errors

• Ejection fraction without the method, or by Teichholz in a ventricle with a segmental abnormality.
• Mass without indexing to body surface area.
• "Hypertrophy" without saying whether it is concentric or eccentric.
• Left atrium by diameter only.
• Diastolic dysfunction concluded from a single parameter.

How Laudário helps

In the Laudário echocardiogram module:

• Body surface area, ejection fraction, mass and left ventricular geometry are calculated from the measurements.
• Diameters, Doppler and volumes in their own fields, with the conclusion assembled from the findings.
• Recommendations in their own tab.

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