Focus on FoCUS: The 4 basic views of the heart
FoCUS = Focused Cardiac Ultrasound
FoCUS consists of 4 basic views of the heart namely parasternal long- and short-axis views, the apical 4-chamber view, and the subxiphoid view, as described in the Rapid Ultrasound in Shock (RUSH) protocol. Here is a quick overview; individual views are discussed in the subsequent posts.
The parasternal views are obtained with the probe positioned just left of the sternum at intercostal space 3 or 4. It’s like slicing the heart in ‘its’ sagittal and transverse planes respectively. As shown in the figure below, long axis of the heart is oblique to that of the body, extending from right shoulder to the left hip.
The apical 4-chamber view of the heart is obtained by placing the probe just below the nipple line at the point of maximal impulse of the heart. It’s like slicing the heart in its coronal plane.
The subxiphoid 4-chamber view is obtained with the probe aimed up toward the left shoulder from a position just below the subxiphoid tip of the sternum. The image is similar to that of Apical 4C except that it is slightly tilted to the right. It is easier to obtain than the apical 4C and helps to assess pericardial effusion quickly. Note that you’ll see the liver on top of the image as we are using it as a window to look at the heart.
It is important to have an idea of all these 4 views of the heart, as some views may not be well visualized depending on the individual patient’s body habitus and position, necessitating an alternative approach.
Below is a nice illustration of these views from PMID 34997377