Right Atrial Mechanics in Healthy Mid-Term Pregnancy-An Analysis from a Three-Dimensional Speckle-Tracking...

Introduction. Pregnancy is characterized by a significant expansion of plasma volume and an increase in cardiac output, necessitating structural and functional adaptations of the cardiac chambers, including the right atrium (RA). To evaluate these changes, three-dimensional (3D) speckle-tracking echocardiography (STE) was used as a validated and sophisticated modality for the concurrent assessment of RA volumetric and functional alterations. This study aimed to characterize RA volumes, volume-based functional indices, and strain parameters in healthy women during mid-gestation, compared with a cohort of non-pregnant controls. Methods. This retrospective cohort analysis included 20 healthy, asymptomatic women in their second trimester (mean age: 29.9 ± 3.0 years; weight: 81.2 ± 14.2 kg; height: 166.9 ± 5.8 cm; body surface area [BSA]: 1.95 ± 0.17 m²). The control group consisted of 30 age-matched healthy non-pregnant women (mean age: 29.9 ± 4.1 years; weight: 58.7 ± 6.5 kg; height: 166.0 ± 5.4 cm; BSA: 1.68 ± 0.11 m²). All subjects underwent comprehensive two-dimensional Doppler echocardiography and 3DSTE. Results. Early and late diastolic RA volumes were significantly reduced, despite preserved end-systolic RA volume. Pregnant subjects exhibited reduced active RA stroke volume and increased passive RA emptying fraction, while all other parameters remained comparable between the groups. No significant differences were observed between groups in end-systolic peak RA global or mean segmental strains, nor in RA strains measured during atrial contraction. However, end-systolic peak regional RA strain analysis revealed decreased basal RA circumferential strain (CS) and increased superior RA-CS in pregnant participants compared with controls. Furthermore, during late diastole (at atrial contraction), superior RA-CS, RA-3D strain, and RA-area strain were significantly higher in healthy pregnant subjects than in controls. Conclusions. Substantial regional changes in RA function were detected by 3DSTE, likely reflecting adaptation to pregnancy-induced plasma volume expansion, and resulting in significant RA volumetric changes.