Fig 1.
Schema of a longitudinal (left) and a transverse (right) four chamber view of the heart, showing ROI placement in the right atrium (ROI 1), left atrium (ROI 2), and right ventricle (reference ROI; ROI 3).
Since in the longitudinal view the ultrasound beam is directed apico-basally, atrial structures are distant and atrial lateral walls are met tangentially. In the transverse view the ultrasound beam meets the lateral atrial walls perpendicularly. ROI, region of interest; RA, right atrium, LA, left atrium; RV, right ventricle; LV, left ventricle.
Fig 2.
Triphasic atrial longitudinal strain dynamics during the cardiac cycle.
ECG, electrocardiogram.
Table 1.
General and echocardiographic characteristics of the study population.
Table 2.
Radial and longitudinal peak strain of regions of interest both ROI reflecting the atria.
Fig 3.
Absolute peak strain (left) and time to peak strain (TTPS) (right) for right (RA) (ROI 1) or left atrium (LA) (ROI 2) in the transverse (trans) or longitudinal (long) four chamber view.
Note that for the sake of visual comparison, numbers for strain are depicted as values so that numbers for both longitudinal and radial strain are “positive”; normally, radial strain (transverse four chamber view) would be negative. The boxplots indicate the median (interquartile range), the whiskers reach from minimum to maximum. The p-value indicates the statistically significant difference between results.
Table 3.
Radial and longitudinal time to peak strain of regions of interest both ROI reflecting the atria.
Fig 4.
Example of a four chamber view of a fetal heart in longitudinal or apical (left) and transverse (right) section.
Note that the interventricular septum and especially the thin interatrial septum are displayed best in the “in plane-view” of the transverse view where the ultrasound waves meet those structures perpendicularly.