Key result
Heart rate predicts age-related declines in LV twist and untwisting velocities in healthy children.
Observational (n=64)
No
Heart rate is an independent predictor of age-related changes in left ventricular torsion parameters in healthy children, highlighting the need to adjust for heart rate when assessing LV mechanics in this population.
Supports adjusting for heart rate in pediatric LV torsion assessment; leaves open prospective validation before practice change.
BACKGROUND AND OBJECTIVES: This study was aimed at assessing left ventricular torsion (LVtor) mechanics using speckle tracking echocardiography (STE), establishing normal reference values of principal LVtor parameters, and analyzing the age-related changes in normal children. SUBJECTS AND METHODS: Eighty children (aged 3 months to 15 years) with normal cardiac function and rhythm were recruited. LVtor parameters including rotations, twist and untwist, torsion, and their rate indices were measured using STE. Age and heart rate related changes of the parameters were analyzed. RESULTS: Speckle tracking echocardiography analyses for LVtor parameters had excellent reliability in 64 of 80 subjects (80%) (intraclass correlation coefficients; 0.93-0.97). Early systolic twist (EST) motions (-8.4--0.1°) were observed in all subjects during an early 20±7% of systolic time intervals. The peak systolic twist and torsion were 17.0±6.5° and 2.9±1.3°/cm, respectively. The peak twist velocity was recorded at 51±13% of systolic time and the peak untwist velocity at 13.8±11.5% of diastolic time intervals. Multivariate analysis showed that heart rate change was an independent predictor of changes in torsion parameters; significantly decreasing LV length-normalized apical and basal rotation, torsion, and twist and untwist rate with increasing age. Isovolumetric recoil rate was independent of change in age and heart rate. CONCLUSION: Left ventricle showed unique torsion mechanics in children with EST, torsion, and untwists. Heart rate was an independent predictor of the change in torsion parameters with aging.
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Kim et al. (2015) conducted an observational in Healthy (n=64). Two-dimensional speckle tracking echocardiography was evaluated on Age and heart rate related changes of left ventricular torsion parameters. In healthy children, heart rate was an independent predictor of age-related changes in left ventricular torsion parameters, with peak twist and untwisting velocities decreasing with increasing age.