The Apical Four Chamber View:
©Walter Rasmussen, R.D.C.S.
Once an apical window is located, orient the transducer index mark generally toward the left side of the body and set the image depth to a few centimeters beyond the border of the atria. Try to position the left ventricular apex and septum directly under the peak of the sector image, with the heart’s axis as vertical as possible on the screen. Ideally, all four chambers of the heart are imaged with the left ventricle, mitral valve and left atrium on the right side of the screen and the right ventricle, tricuspid valve and right atrium on the left. A quick way to confirm that the transducer orientation is correct is to observe that the left ventricle, which has thicker walls, should be on the right side of the screen. In actual practice, the apical four chamber view often does not image the right ventricle adequately and the transducer needs to be shifted medially to specifically capture the whole RV chamber and right ventricular free-wall.
Ideally, the left ventricular outflow tract and aortic valve should not be visible in the apical 4-chamber view. These anatomical features can be eliminated by rotation and angulation of the transducer. Sometimes, however, optimal visualization of the left ventricular endocardium is achieved only with the transducer angled just a bit anteriorly, thus catching portions of the aortic root. Additionally, it may be impossible to completely eliminate the aortic root from the 4-chamber image if it is dilated.
In day to day practice, there will almost always be some elements of the apical four chamber view which are not possible to capture from only one transducer position and angle. It is therefore often necessary to focus on those elements which can be imaged together within one clip and then proceed to the elements which could not be adequately imaged as extra, “off-axis” clips and still staying as close as possible to the four chamber plane. The typical echocardiogram will therefore have multiple versions of each apical view which, in combination, render a complete and accurate view of everything required.