Background Two-dimensional (2D) strain imaging has become an
important tool in assessing subclinical myocardial dysfunction in
children. However, there are no pediatric reference values for vendor
independent strain software. The aim of this study was to estimate 2D
strain values in a cohort of healthy children using Tomtec cardiac
performance analysis (CPA), a vendor independent software.
Methods Transthoracic echocardiograms of healthy pediatric
outpatients (0-18yrs) were retrospectively analyzed from the Vanderbilt
Pediatric Heart Institute using CPA. Cardiac assessment included global
longitudinal strain (GLS), global longitudinal strain rate (GLSR),
global circumferential strain (GCS), global circumferential strain rate
(GCSR). Mean strain values with standard deviation (SD) are reported.
The Wilcoxon rank sum test, linear regression and one-way analysis of
variance were used to assess differences among the various groups.
Results Among 142 children analyzed, 79 (56%) were male, and
the median age was 5.5 (range, 0-18) years. The mean (SD) strain values
were GLS -19.3 ± 3.4, GLSR -1.1 ± 0.22; GCS -24.7 ± 4.3, GCSR -1.5 ±
0.28. Age accounted for <8% of variation in GLS, GCS and
GSCR. However, for GLSR, there was a statistically significant
difference between younger and older age groups with higher GLSR in the
younger age group. Age accounted for ~25% of variation
in GLSR (R 2 = 0.25, P < 0.001). There were
no significant differences in strain based on sex. Conclusion
We report normal reference values in healthy children by age for strain
using CPA. These values are necessary for the interpretation of 2D
strain imaging for both clinical care and research.