Left Atrial Volumes and Strains in Healthy Mid-Term Pregnancy-A Detailed Investigation from a Three-Dimensional...

Introduction: Gestational physiology is characterized by an expansion of plasma volume and an elevation in cardiac output. Given the scarcity of existing data on pregnancy-related left atrial (LA) volumetric and functional features, this study aims to define LA volumes, volume-based functional properties and strains in healthy subjects during mid-term pregnancy. Methods: The present study comprised 19 healthy women in mid-term pregnancy (mean age: 30.5 ± 2.7 years, weight: 81.7 ± 14.0 kg, height: 166.9 ± 5.7 cm) without any symptoms, known diseases or other conditions, which could affect the results. Their results were compared to those of 43 healthy non-pregnant women (mean age: 28.6 ± 4.9 years, weight: 59.9 ± 8.5 kg, height: 167.8 ± 7.6 cm). All participants underwent comprehensive two-dimensional Doppler echocardiography with three-dimensional speckle-tracking echocardiography (3DSTE). Results: Thicker interventricular septum, increased left ventricular ejection fraction and impaired early and late transmitral flow velocities could be detected in healthy pregnant subjects as compared to those of non-pregnant individuals. End-systolic maximum LA volume was increased with elevated stroke volume and emptying fraction. While early diastolic LA volume was preserved with elevated stroke volume and emptying fraction, late diastolic LA volume, stroke volume and emptying fraction remained unchanged. However, indexed LA volumes did not differ between the groups. Among end-systolic peak global LA strains, only LA longitudinal strain (LS) was increased, while all others remained unchanged. Among regional strains, basal, midatrial and superior LA circumferential strain (CS) and LA-LS were increased except for basal LA-CS, which was impaired. Among late diastolic LA strains at atrial contraction, none of them showed any significant changes in healthy pregnant subjects compared with those of non-pregnant women. Conclusions: With a detailed 3DSTE study, elevated end-systolic LA volume and preserved diastolic LA volumes, together with enhanced end-systolic LA reservoir and early diastolic LA conduit functional properties, could be detected with features of preserved late diastolic booster pump function in healthy women during mid-term pregnancy (second trimester). When comparing indexed LA volumes, no significant difference could be confirmed between the pregnant and non-pregnant groups. This suggests that the increased end-systolic LA volume may be an adaptation to increased body weight.