Parasternal short axis
2D anatomy at the aortic level. One can see the RVOT in the anterior chest (top part of the clip) with the pulmonary valve. We can also see the aortic valve (tri-leaflet) opening and closing, sitting on top of the left atrium. On the left side of the screen, we can see the right atrium next to the left atrium.
2D anatomy image of the aortic valve: confirmation of the tricuspid opening of the aortic valve – Fusion of leaflets may not be obvious and the valve needs to be seen opening in a tri-leaflet manner
M-Mode at the level of the aortic valve for the La:Ao ratio. A ratio may be increased in the context of LA dilation or hypoplastic aorta. LA diltation may occur in the context of increased pulmonary venous flow (such as in the context of a large PDA that is left to right). In the context of a large inter-atrial septal defect, the LA may decompress and the ratio may be within normal limit despite the presence of a large ductus.
2D anatomy and zoom on left coronary artery (LCA) osteum and right coronary artery osteum. Delimitation of coronary system anatomy including division with circumflex coronary from LCA. Do not be fooled by epicardial folds that may seem to be the coronary artery. It is important to identify coronary artery origins in the context of poor ventricular function. Indeed, one may have abnormal implantation of the LCA or RCA, single coronaries, etc. In ALCAPA (anomalous left coronary artery from the pulmonary artery), the coronary artery will come from the pulmonary artery. This is a good view to zoom in and do measurements of coronary if dilation. In newborns, coronary dilation may be present in the context of pulmonary hypertension with significant RA end-diastolic hypertension (since the coronary sinus is usually draining in the right atrium).
Color Doppler of LCA with demonstration of flow during diastole with low (Nyquist) velocity. The flow should be red in diastole (coming towards the transducer).
Re-demonstration of coronary flow at low velocity.
Visualization of the right coronary artery connection to the aortic root. It is important to show the clip in movement, so that it is confirmed that it is not an artefact. Still-images with a vessel may not be sufficient to show the opening of the RCA to the root.
The flow in the RCA is difficult to obtained. Often, the transducer is angulated in a way that the flow is not obtainable. However, with angulation manipulation one may appreciate the flow at low velocity in diastole of the RCA. A P-W doppler can be done to confirm the flow during diastole.
View of the main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA).
Again, view of the main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA). This time, we can appreciate the pulmonary valve proximal to the MPA.
Again, view of the main pulmonary artery (MPA), right pulmonary artery (RPA), and left pulmonary artery (LPA). Colour box is applied. Blue colour indicates that the flow is going away from the probe, filling the MPA - RPA - LPA.
In this example, one can appreciate a red "flame", which represents a high velocity restrictive patent ductus arteriosus with left to right shunting (red: coming towards the transducer, hence towards the MPA).
Sweep delineating the restrictive ductus arteriosus as it travels from the MPA to the aorta.
Sweep from the base of the LV (mitral valve), which appears like a "fish mouth", to the apex of the LV. This is a good view in order to evaluate function of the LV (posterior wall and septum), the septal configuration, the presence of a VSD (would need to do the same scan with a colour box on the septum), the presence of effusion. In the context of higher pulmonary vascular resistance (immediate post-natal period), the flow through a VSD may be at low velocity, and as such the velocity filter ("Nyquist") should be decreased in order to detect (as much as possible) the presence of a VSD. In the context of structural evaluation (done by cardiology), the scanning of the septum should be done in every views at the first echocardiography to evaluate the presence of a VSD. Consider CW Doppler across detected VSD if aligned with jet.
View of the RV and LV in cross-sectional area at the level of the base of the left ventricle.
M-mode can be taken in PSA for quantification of SF (if not done in the PLA). M-Mode can also be used for measurements of septum and posterior wall diameters in diastole (for evaluation of hypertrophy).
2D capture of the RV-LV interaction at the mid-papillary level. Evaluation of septal curvature at the end of systole. Septal curvature was described and validated for the end of systole. Clinically, septal curvature is often appreciated throughout the cardiac cycle: diastole and systole.
This view is useful for measurement of eccentricity index (more in the pulmonary hypertension section).
At mid-papillary muscle level, one can evaluate septal-curvature (configuration of the inter-ventricular septum). At peak of systole, when both ventricles are contracted, pulmonary and aortic valve are open. RV pressure will equalize with pressure in PA; LV equalize with Aorta (assuming no congenital heart defect and no RVOT/LVOT obstruction). Usually, the LV is under higher pressures than RV in systole (contraction). As such, LV has a round aspect in this view and the RV crescentic (surrounds LV) in systole. As pressure rises on RV side (or pressure decreases on LV side), the RV afterload can become iso-systemic (same as pressure on the LV compartment) or supra-systemic (higher pressure than on LV side). Because there is a shared wall:
About 2/3 systemic to iso-systemic = Flat Interventricular septum at peak of contraction - D-Shape LV
Supra-systemic = Bowing septum into the LV cavity (which eventually can "pancake" the LV and impede on LV cavity).
With persistent increased afterload, RV hypertrophies and dilate.
The septal configuration can also be appreciated during diastole, and indicates end-diastolic pressures. Hence, there can be flattening of the septum in diastole in the context of increased RV end-diastolic pressures (such as in the context of volume overload, or progressive RV diastolic failure).
LV end-systolic eccentricity index as a way to quantify septal deformation
Eccentricity index (RV-LV Interaction: D1/D2) (Normal < 1.23)
RV/LV ratio (marker of RV dilation: D3/D2) (Normal < 1.00)
Jone JG, Ivy D, Frontiers in Pediatrics - November 2014 , Volume 2, Article 124
Nagiub M, Echocardiography 2015;32:819–833
The following image is from the above article. The article outlines:
Systolic septal flattening recognized at EIs ≥ 1.15.
High inter-observer agreement for EIs.
Quantitative parameters of RV systolic function were impaired only at EIs ≥ 1.3.
Reference: Echocardiography 2016;33:910–915
Eccentricity index (RV-LV Interaction: D1/D2)
Normal < 1.23
RV/LV ratio (marker of RV dilation: D3/D2)
Normal < 1.00
Examples of progressive septal flattening at end of systole. One can appreciate on the last panel the severe RV dilation and pan-caking of the LV.
Area at end of systole (contraction) and end of diastole (filling) can be traced at mid-papillary muscle view. Area x 5/6 x LV-length (in systole or diastole in apical 4 chamber view) can be used to estimate volumes and calculate the corresponding ejection fraction (EF), where EF = (End-diastolic volume - End systolic volume)/End-diastolic volume in %.
Here are examples of PW-Doppler at the tip of the pulmonary valve. This is used for calculation of PAAT/RVET as well as RVOT-VTI.
Here is an example of the PW-Doppler enveloppe in the RVOT of a patient with a PDA (left to right). The triangular shape indicates increase afterload, which may be secondary to pressure transmission from the systemic compartment.
On the left, and below, we can see some examples of parabolic spectral enveloppes of the RVOT-PW Doppler in patients with no overt signs of pulmonary hypertension or increased RV afterload. On the contrary, we can appreciate the triangular aspect of the RVOT-Doppler enveloppe on the right panel where the PAAT is 20.85 msec and the RVET is 271.10 msec, giving a ratio of: 0.08 (well below the 0.3 suspicious of pulmonary vascular disease).
Example of PW-Doppler in the right pulmonary artery. In this particular example, one can appreciate the mid-systolic notch associated with increased pulmonary vascular resistance. More examples are provided in the section dedicated to pulmonary hypertension.
Here, the PAAT/RVET is 0.33 (103/315) - and the profile is parabolic. The VTI of the RVOT is 19.4 cm.
Low RVO (≤150 mL/kg/min) - Reference: Popat H. et al. Neonatology 2019;115:13–20
Pulmonary insufficiency: same concept as TR
Pulmonary valve is closed during diastole
If RV/PA dilation, the PV annulus dilate, valve becomes less competent and PI appears.
Early Insufficiency jet speed gives you estimate of mean PA pressure; end diastolic of diastolic PA pressure
Diastolic pulm pressure (DPAP) estimated from pulm regurgitation jet from velocity of end-diastolic PI velocity
Estimated Diastolic PAP = 4 (end-diastolic PI velocity)2 + estimated RA pressure (RA pressure should be equivalent to end-diastolic RV pressure, usually around 0-5 mmHg in normal conditions; but may be increased in the context of RV diastolic dysfunction).
Estimated Mean PAP = 4 (early diastolic PI velocity)2 + estimated RA pressure
Position of the probe on the chest of the baby to acquire parasternal short axis view (this may slightly depend on each newborn).