Speckle Tracking Analysis to Evaluate the Size, Shape, and Function of the Atrial Chambers in Normal Fetuses at 20-40 Weeks of Gestation

Objectives The purpose of this study was to use speckle tracking analysis to evaluate the size, shape, and function of the atrial chambers in normal fetuses and develop a z-score calculator that can be used in future studies in fetuses at risk for cardiovascular disease. Methods The control group consisted of 200 normal fetuses examined between 20 and 40 weeks of gestation in which speckle tracking analysis of right (RA) and left (LA) atrial chambers was performed. The atrial end-diastolic and end-systolic endocardial borders for each chamber were identified from which measurements of atrial length, width, area, and volume were computed. Equations were derived using fractional polynomial regression analysis to compute z-score equations. Results The LA end-diastolic volume, RA and LA end-diastolic area, length, base width, and mid-chamber widths increased with gestational age and fetal size. Left atrial emptying and ejection volumes increased with gestational age and fetal size. The fractional area change was significantly less for the RA than the LA. The LA base and mid-chamber fractional shortening were significantly greater than the RA. There was a significant difference between the RA and LA global contractile strain. Conclusion Mean and standard deviation equations for each of the measurements described in this study were computed to create a z-score calculator that can be utilized in the clinical environment when evaluating fetuses with suspected atrial pathology that could alter the size, shape, and function of the atrial chambers.