Right atrial volumes and strains in healthy adults: is the Frank-Starling mechanism working?—detailed analysis from the three-dimensional speckle-tracking echocardiographic MAGYAR-Healthy Study

Abstract

Background: With larger blood volume flowing into a cardiac chamber, by stretching muscle fibers, increased contraction force could be detected. This phenomenon is called Frank-Starling mechanism, allowing the output of a cardiac chamber to be synchronized without external regulation. The purpose of the present study was to investigate the Frank-Starling mechanism in the right atrium (RA) represented by its volumes, volume-based functional properties and strains respecting the cardiac cycle in healthy adults by three-dimensional (3D) speckle-tracking echocardiography (3DSTE). Methods:The present single center retrospective cohort study comprised 179 healthy adult volunteers (mean age: 33.2±12.0 years, 92 males), in whom complete two-dimensional Doppler echocardiography with 3DSTE was performed. Subjects were divided into 3 groups according to the mean value of maximum RA volume (V max ) ± standard deviation: V max <30 mL, 30 mL ≤ V max <60 mL and V max ≥60 mL.Results: All RA volumes respecting the cardiac cycle of all subjects and calculated separately for females and males and their indexed equivalents increased with V max . RA stroke volumes increased with V max regardless of the phase it was measured in. While total atrial emptying fraction representing the reservoir phase remained unchanged with the increase of V max , a significant increase in passive atrial emptying fraction representing the conduit phase could be detected, in case of V max >60 mL (28.9%±15.1% vs. 32.5%±12.6%, P<0.05).Active atrial emptying fraction representing the booster pump function did not change with the increase of V max . Most global and mean segmental peak RA strains did not show significant changes with increasing RA volumes except for the RA area strain, it was the largest when V max was larger than 60 mL (64.7%±44.9% vs. 83.3%±49.4%, P<0.05). RA circumferential, longitudinal and area strains at atrial contraction decreased with increasing V max , RA radial and 3D strains did not change significantly with increasing V max .Conclusions: Increasing RA volumes do not cause significant increase in RA contractility represented by strains, but reduction in strains in longitudinal and circumferential directions could be detected in enddiastolic booster pump function. In contrast to the left atrium, obvious signs of Frank-Starling mechanism could not be detected in case of the RA.

Three-Dimensional Speckle-Tracking Echocardiography-Derived Tricuspid Annular Dimensions and Right Atrial Strains in Healthy Adults—Is There a Relationship? (Insights from the MAGYAR-Healthy Study)

“…However, transmural fiber angle distribution is heterogeneous throughout different regions of the atria, which could partially explain why associations with RA-LS and RA-CS could not be detected [ 23 ]. In a recent study, the Frank–Starling mechanism for RA was examined and demonstrated that increasing RA volumes do not cause a significant increase in peak RA strains representing reservoir function in systole [ 11 ]. This finding was extended in this study, demonstrating that increased RA contractility in longitudinal direction represented by peak RA-LS is associated with larger V max and lower V min .…”

“…ECG, 2DE, and 3DSTE showed results in the normal reference ranges. The present study is part of the M otion A nalysis of the heart and G reat vessels b Y three-dimension A l speckle-t R acking echocardiography in Healthy subjects (MAGYAR-Healthy) Study aiming to investigate physiological relationships among 3DSTE-derived and other parameters in healthy adults (’Magyar’ means ’Hungarian’ in the Hungarian language) [ 8 , 9 , 10 , 11 ]. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013, and the updated versions).…”

Similarities and Differences between Three-Dimensional Speckle-Tracking Echocardiography-Derived Left and Right Atrial Volumes and Volume-Based Functional Properties in the Same Healthy Adults—A Detailed Analysis from the MAGYAR-Healthy Study

“…Not only is the spread of cardiac magnetic resonance imaging and computer tomography observed, but new echocardiographic procedures have appeared as well. STE is one of the most recent developments, which can see and visualize the heart and its cavities, including both atria, using 3D models [7,8,10,11]. Three-dimensional speckle-tracking echocardiography is suitable for detailed atrial volumetric and volume-based functional analysis using SVs and EFs, respecting the cardiac cycle [7,8,10,11].…”

“…Three-dimensional speckle-tracking echocardiography-derived data acquisitions were done immediately after complete 2D echocardiography, according to recent guidelines and practices. The present retrospective cohort study is part of the 'Motion Analysis of the heart and Great vessels bY three-dimensionAl speckle-tRacking echocardiography in Healthy subjects' (MAGYAR-Healthy) Study, which was organized at the University of Szeged for the purpose of carrying out physiological clinical studies ('Magyar' means 'Hungarian' in Hungarian language) [1,8,[10][11][12]. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013).…”

“…Automatic sequential analysis (reconstruction) was performed for the complete endocardial LA/RA surface. The following LA/RA volumes have been calculated, taking into account the heart cycle [7,8,10,11] (Figures 1 and 2):…”