Feasibility and Reproducibility of Left Ventricular Longitudinal Strain Measurements in Pre-Term Babies using Two Dimensional Speckle Tracking Echocardiography

Background: In adults, speckle tracking strain echocardiography (STSE) has shown to be less load dependent, more reproducible and able to better identify subclinical left ventricular (LV) dysfunction than ejection fraction. STSE in the neonatal population has not been as extensively studied as this population has unique challenges such as very high heart rates and difficulty in obtaining a full range of images from the apical window. Methods: Standard apical 4chamber, 2chamber and long axis images were taken at a frame rate of 95 frames per second (fps) and analysed using dedicated STSE software (aCMQ, Philips Medical Systems). Regional and global longitudinal strain (GLS) was determined from each apical view. The ease of acquisition, image quality, intra and inter observer variability were also assessed. Results: Twenty-six neonates (gestation 28.9 ± 5 weeks, weight 1.6 ± 1.2kg) had STSE analysis performed. Both the apical 2 chamber and long axis views were more difficult to obtain than the 4 chamber view. Both GLS (-28.1 ± 2.4%) and 4 chamber strain (-28.6 ± 2.8%) were well correlated (intra-class correlation (ICC) 0.89, p<0.0001). There was good intra (ICC 0.88, p<0.0001) and inter (ICC 0.83, p<0.0001) operator reproducibility for STSE measurements. Conclusion: In the preterm neonate population STSE is a feasible and reliable method of assessing left ventricular strain. The STSE of the Apical 4 chamber is reflective of GLS and may be used in its place in neonates where the other apical views are difficult to obtain.