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Strain Z-Scores

Age-based z-scores for LV and RV speckle-tracking strain in children (Romanowicz 2023, n=1032)

For educational and informational purposes only. Verify all results before clinical application.

years
%

Enter strain as a negative percentage (e.g., -22 for GLS of -22%)

References

  1. Romanowicz J, Ferraro AM, Harrington JK, et al. Pediatric Normal Values and Z Score Equations for Left and Right Ventricular Strain by Two-Dimensional Speckle-Tracking Echocardiography Derived from a Large Cohort of Healthy Children. J Am Soc Echocardiogr. 2023;36(3):310-323.[DOI]

Reviewed by Daniel Diaz-Gil, MD · Last updated March 2026

Medical disclaimer

This tool is for educational and informational purposes only. It is not a substitute for professional clinical judgment. Always independently verify results before making clinical decisions.

Professional Resources — Tools used by pediatricians for cardiac assessment

Park's Pediatric Cardiology for Practitioners, 7th EdComprehensive reference for pediatric cardiology evaluation and management~$95via AmazonEchocardiography in Pediatric and Congenital Heart Disease, Lai et alDefinitive echo reference with z-score tables and imaging protocols~$180via AmazonBoardVitals Pediatric Cardiology QbankBoard-style questions for pediatric cardiology certificationsubscriptionvia BoardVitals
Clinical Reference & Evidence

Pediatric Strain Z-Score Calculator

Overview

This calculator provides age-based z-scores for myocardial strain measured by two-dimensional speckle-tracking echocardiography (2D-STE) in children. It uses piecewise polynomial regression equations from Romanowicz et al. 2023, derived from 1,032 healthy children under 21 years on two commonly used vendor platforms: Philips QLAB 10.8 and TomTec AutoSTRAIN.

What It Measures

Philips QLAB 10.8:

  • LV apical 4-chamber longitudinal strain (LV A4C LS)
  • LV circumferential strain (LV CS)

TomTec AutoSTRAIN:

  • LV apical 4-chamber longitudinal strain (LV A4C LS)
  • RV apical 4-chamber longitudinal strain (RV A4C LS)
  • RV free wall longitudinal strain (RV FW LS)

When to Use

  • Screening for subclinical ventricular dysfunction in children receiving cardiotoxic chemotherapy
  • Monitoring ventricular function in cardiomyopathy (dilated, hypertrophic)
  • Assessing RV function in pulmonary hypertension or post-surgical congenital heart disease
  • Evaluating myocardial recovery after myocarditis
  • Serial monitoring of ventricular function in Kawasaki disease

Key Clinical Points

  • Strain values are vendor-specific. Always match your analysis platform to the correct equation set.
  • Strain varies nonlinearly with age, peaking at 4-5 years then declining through adolescence.
  • R-squared values are intentionally low (0.1-0.2) because strain has a weak relationship with age. This is a known limitation acknowledged by the authors.
  • QLAB 10.8 and AutoSTRAIN show good agreement for LV LS, especially in neonates and infants.
  • RV strain z-scores (AutoSTRAIN only) are the first published for a large pediatric population.
  • Enter strain as a negative percentage (e.g., -22 for GLS of -22%).

Limitations

  • Vendor-specific: equations apply only to Philips QLAB 10.8 and TomTec AutoSTRAIN. Do not use with GE EchoPAC or older QLAB versions.
  • Low R-squared means the z-score normal range is wide. Small differences near the threshold should be interpreted cautiously.
  • Derived from a single-center US population (Boston Children's Hospital).
  • No circumferential strain equation for AutoSTRAIN (not available at time of study).
  • Frame rate, image quality, and tracking algorithm affect strain values.

Reference

Romanowicz J, Ferraro AM, Harrington JK, et al. Pediatric Normal Values and Z Score Equations for Left and Right Ventricular Strain by Two-Dimensional Speckle-Tracking Echocardiography Derived from a Large Cohort of Healthy Children. J Am Soc Echocardiogr. 2023;36(3):310-323. DOI: 10.1016/j.echo.2022.11.016