4 Levels
The parasternal short axis view is obtained by rotating the probe 90 degrees counter clockwise so that the probe orientation marker now faces the patients left shoulder. There are 4 levels at which images are obtained in the short axis plane:
- Aortic Level
- Basal / Mitral Level
- Mid Papillary Level
- Apical Level
The 4 levels are further detailed in the following video. For purposes of point of care ultrasound, we will consider the mid-papillary view in more detail.
Mid Papillary Parasternal Short Axis
How To Obtain This View:
The PSAX view is obtained by rotating the transducer 90 degrees clockwise from the PLAX view. The probe should be in the left parasternal 3rd to 4th intercostal space, with the probe marker facing the left shoulder.
The patient should lie in the left lateral decubitus position with the left arm under the head.
The 4 LV walls are seen – Anterior, Inferior, Septal & Lateral. Presence of papillary muscles confirms that the probe is at mid-papillary level.
Useful For Assessment Of:
Left Ventricle:
All 4 walls of the LV can be seen. This makes this view ideal for assessment of global and regional LV systolic function. The mid-papillary segments of the LV are usually imaged in FCU, but the apical and basal segments of the LV can be visualized with probe movement towards the apex or base of the heart. Assessment of intravascular volume can be made by looking at the end diastolic and end systolic LV cavity sizes.
Right Ventricle:
RV size and contractility should be assessed in combination with the other FCU views for a complete evaluation.
Interventricular Septum:
The PSAX view is ideal to look for septal flattening or paradoxical septal movement which is present in conditions associated with RV volume and / or pressure overload.
Pericardial Space:
Finally, pericardial effusions can be picked up. Circumferential presence of fluid indicates an effusion of reasonable size.