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Standard Parasternal Long Axis View

PLAX probe view.jpg

In this position the ultrasound beam (light blue) cuts the heart like to create the 2D image below 

Place the  transducer just left of the sternum in the 4th or 5th intercostal space. The transducer marker (arrow) should be facing the right shoulder.


The most anterior structure is the right ventricular outflow tract (RVOT). The left ventricle (LV), left atrium (LA) and descending aorta are visible below. An ideal PLAX view doesn't show the LV apex and the LV wall are almost horizontal.  Also seen are the anterior and posterior mitral valve leaflets (AML, PML), aortic valve (AV) and descending aorta (DA). 

PLAX view.jpg

This is a video clip of an ideal view 

Aortic and Mitral Zoomed in View

Zooming in on the aortic valve and mitral valve allows for better visualization of leaflet structures. Usually the right and non coronary cusps of the aortic valve are seen here, however with off-axis imaging, the left coronary cusp may also be seen. RCC - right coronary cusp, NCC - non coronary cusp.


Ascending Aorta

By moving the transducer up an interspace, one can see the proximal ascending aorta. This is useful in those who have dilated or calcified aorta root and enlarged ascending aorta.

Teaching points for this view

1. For a proper PLAX view you shouldn't see the apex; if you need to see the apex in this view (for LV thrombus or otherwise) move the probe more apical

2. A quick assessment of LV function can be made by looking at the descent of the basal structures  (how much does the mitral valve annulus and aortic valve move toward the apex in systole and also the E point septal separation which can tell you about function and LV dilation. 

3. Make sure for your measurements that you measure the septum and posterior wall in true end diastole. Measure the LVOT diameter in mid systole. Measurements are shown here.

4. This is a great view to assess for MV prolapse, MR jet direction and to measure MR vena contracta. For prolapse that is not at A2 or P2 (most common scallops seen here) you need to tilt the probe off axis to see A3P3 and A1P2 scallops. 

5. This is also a good view to measure AR vena contracta width.

6. A pericardial effusion in this view can be seen anteriorly near the RVOT and posteriorly. Posteriorly a pericardial effusion will be located anterior to the aorta. Pleural effusions are posterior to the aorta.


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