Calculate relative wall thickness (RWT) on echo from posterior wall thickness and LV diameter, then classify LV geometry with RWT and LV mass index.

Educational adult echocardiography estimate, not a diagnosis. Use end-diastolic measurements from the same study. Geometry requires BSA-indexed LV mass from the matching linear method; children and other indexing methods need different references.

RWT comparison cutoff

Blank uses the adult reference cutoff 0.42. A different value produces a custom comparison.

Educational use only; not medical advice or a diagnosis. LV geometry labels and cutoffs can vary by lab and must be interpreted by a clinician using a complete echocardiogram and clinical context. If you have chest pain, fainting, shortness of breath, palpitations, or known heart disease, seek urgent care or contact a clinician.

Relative Wall Thickness Formula

RWT = 2 × PWT / LVD

Variables:

  • RWT is the Relative Wall Thickness (unitless)
  • PWT is the posterior wall thickness at end diastole
  • LVD is the LV internal diameter at end diastole, in the same unit as PWT

To calculate Relative Wall Thickness, divide the posterior wall thickness by the LV diastolic diameter, then multiply by 2.

Clinical guidance (cutoffs & methods)

The ASE/EACVI adult chamber-quantification reference uses increased RWT > 0.42 and linear-method LV mass index upper limits of 95 g/m² for women or 115 g/m² for men, indexed to body surface area (BSA). Equality is not increased. These LVMI limits are not interchangeable with 2D, 3D, CMR, height-indexed or pediatric references. Normal geometry is a pattern, not proof of normal cardiac health; use your echo lab’s method and a clinician’s complete assessment.

How to Calculate Relative Wall Thickness?

The following steps outline how to calculate the Relative Wall Thickness.

  1. First, determine the posterior wall thickness. 
  2. Next, determine the LV diastolic diameter. 
  3. Next, gather the formula from above = RWT = 2 * PWT / LVD.
  4. Finally, calculate the Relative Wall Thickness.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

posterior wall thickness = 0.78 cm

LV diastolic diameter = 4.0 cm. RWT = 2 × 0.78 / 4.0 = 0.39 (unitless).

FAQs

What is the significance of measuring Relative Wall Thickness (RWT)?
Measuring RWT is crucial for assessing the geometry of the left ventricle, which can provide valuable insights into cardiac health. It helps in identifying patterns of remodeling or hypertrophy when interpreted alongside other echocardiogram measurements.

Can Relative Wall Thickness be used to diagnose heart conditions?
RWT helps classify LV geometry (e.g., concentric remodeling/hypertrophy vs eccentric hypertrophy) and is interpreted alongside LV mass index and the full echocardiogram report. It is not sufficient to diagnose specific cardiomyopathies such as hypertrophic cardiomyopathy (HCM).

What are the normal values for Relative Wall Thickness?
A commonly used cutoff is 0.42: RWT ≤ 0.42 is generally considered not increased (normal), and RWT > 0.42 is considered increased. Interpretation of LV geometry (normal geometry vs concentric remodeling/hypertrophy vs eccentric hypertrophy) depends on LV mass index in addition to RWT.

How often should Relative Wall Thickness be measured?
RWT is typically reported when an echocardiogram is performed for a clinical reason. The need for repeat echocardiograms depends on symptoms, diagnoses, and clinician guidance.