10
Apr
2017

Written by Judith Buckland, MBA, RDCS, FASE and Andrea Fields, MHA, RDCS

Calculating LVM via 2D Truncated Ellipsoid Method

In earlier blogs we discussed calculating the left ventricular mass (LVM) via the 2D Linear Cubed Method with assumes an ellipse shape with a major/minor axis ratio of 2:1. We received a follow up question from a reader: “Can you please provide the reference for NOT using cube method formula when major minor axis ratio is distorted?”

Thank you for the request, we’d love to provide some additional information. The ASE guidelines do provide information on calculating the LVM via the truncated ellipsoid 2D method. We will review the step by step method for this formula. Unfortunately this method is also problematic in the presence of shape distortions. The recommendation from ASE is to report LVM in hypertensive patients with a normally shaped LV via either the Linear Cubed M-Mode method or the 2D truncated ellipsoid method. “In labs that use 3D echo routinely 3D LVM should be considered – especially in abnormally shaped ventricles with asymmetric or localized hypertrophy”.

2D Truncated Ellipsoid

This method is performed in two steps! If your machine is not setup with the proper measurement calculations for these specific values, then contact your vendor to add them.

Step 1: Mean Wall Thickness Ratio

Parasternal short axis (PSAX) at mid-papillary level
Trace the epicardial (‘LVAd Epi’) and endocardial (‘LVAd Endo’) areas (cm²)
Do NOT trace the papillary muscles – the papillary muscle are considered part of the LV cavity

Step 2: LV Length

In the apical 4 chamber view

Zoomed LV
End-diastole
Measure the length from the apex to base of ventricle (cm).

Your ultrasound machine should perform the calculation if you select the 2D truncated ellipsoid method when entering these values into the measurement package and should display thee LVM indexed with BSA.

Reference Range

Advantages:

Partial correction for shape distortions
Less dependent on geometrical assumptions than the linear measurements

Limitations:

Good image quality and properly oriented parasternal short-axis views (no oblique planes) are required
Good epicardial definition is required
Cumbersome methodology
Higher measurement variability
Few published normative data
Limited prognostic data

3D Echocardiography

The American Society of Echocardiography reminds us in the latest guidelines that 3D Echocardiograhy is the only echocardiographic technique that measures myocardial volume directly, without geometric assumptions regarding LV shape and distribution of wall thickening. Therefore this technique is promising and may be used in abnormally shaped ventricles or in patients with asymmetric or localized hypertrophy. Unfortunately, limited upper normal limits of 3D echocardiographic LV mass data are currently available in the literature but are insufficient to substantiate recommendations for reference values.

Be sure to check out our earlier blogs related to LVH:

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References

https://acc.org/latest-in-cardiology/articles/2016/02/02/08/21/approaches-to-echocardiographic-assessment-of-left-ventricular-mass?w_nav=Tab
Marwick, T. H., PhD, Gillebert, T. C., MD, & G. A., MD. (2015). Recommendations on the Use of Echocardiography in Adult Hypertension. JASE,28(7), 1-12. Retrieved March 1, 2017, from http://asecho.org/wordpress/wp-content/uploads/2015/07/2015_Hypertension.pdf
Lang, R. M., MD, Badano, L. P., MD, & Mor-Avi, V., PhD. (2015). Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging. JASE, 28(1), 1-53. Retrieved March 1, 2017, from http://asecho.org/wordpress/wp-content/uploads/2015/01/ChamberQuantification2015.pdf

LVH