2.2. Data Acquisition and Analysis
Transthoracic ultrasonography images were obtained by an experienced ultrasonographer using General Electric Vivid 9 system equipped with an M4S probe (frequency range: 1.5–4.0 MHz). Grey-scale 2-dimensional (2D) ECG-triggered, apical 2-chamber (AP2C), apical long axis (APLAX), apical 4-chamber (AP4C), and subcostal 4-chamber (SU4C) cine-loops were recorded with frame rates ranging from 42 to 70 fps for offline analysis.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348630/

First, obtaining usable apical 4-chamber (AP4C) images - the view used to measure TAPSE and S' - may be difficult in ventilated or post-surgical patients; subcostal 4-chamber views (SC4C), however, are generally obtainable.

https://clinicaltrials.gov/ct2/show/NCT05452044



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Note added at 11 mins (2023-03-28 18:47:12 GMT)
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s it turns out, visual estimations of global function approximate formal quantitative methods in trained observers and we will use this to out advantage by comparing the different ranges and we will use the parasternal short axis view and apical 4 chamber view for comparison purposes.

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Fractional area change (FAC) is a measurement technique on 2D ultrasound and used on the Parasternal short axis view at the mid-papillary level. It measures the change in area that happens in systole and diastole and is used as a surrogate for Ejection Fraction but FAC is not EF. EF is based upon volume as opposed to FAC which is based on area.

https://www.showmethepocus.com/ejection-fraction-left-ventri...

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Note added at 15 mins (2023-03-28 18:50:48 GMT)
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El plano Apical 4 Cámaras (Ap4C) “corta” al corazón en el plano transversal.

https://techneymedeos.com/31tips-de-ultrasonografia-cardiaca...

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Note added at 40 mins (2023-03-28 19:15:59 GMT)
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The apical 4 chamber view is found by placing the probe at the apex located at the apical impulse. The left chambers are seen on the right of the screen and the right chambers on the left of the screen. Fix the image when the 4 chambers look the largest. The important point is to visualize the left ventricular apex directly under the probe on the screen. This view is suitable for evaluation of 4 chamber balance and wall motion abnormalities and abnormalities of the attachment site of atrioventricular valves. It is also suitable for the measurement of left ventricular volume, left ventricular ejection rate, and for recording of pulmonary venous blood flow patterns.

https://www.jss.org/english/standard/standardization_ca/apic...