The next step in the evaluation of our patient is an assessment of precordial movement, and I'm placing my hand at the apex, even feeling inferolaterally, and I feel no movement. Is this an additional clue to the diagnosis of our patient?
Discussion
An absent palpable apical impulse may occasionally occur in normal patients, particularly if they are obese. However, it may also be an important negative finding, especially if the patient has been examined in the left lateral decubitus position. It is strong evidence against the presence of disease that causes left ventricular enlargement, where the apical impulse is usually enhanced. It may also be a clue to right ventricular enlargement, where the anteriorly located right ventricle pushes the left ventricle posteriorly.
Assess left sternal edge
Let us continue our evaluation of precordial movement by assessing the left sternal edge. I actually feel two areas of movement, not only in the lower left sternal edge area, but also in the second interspace I feel an impulse. Let's evaluate the contour of that impulse together and its timing. Let's use the cotton swab on the carotid and another cotton swab placed over the impulse at the second left interspace. Let us observe together. [Cut-away]
Precordial impulses graphic
Precordial impulses are not normally palpable at the left sternal edge. When present, they may occur in two areas. The most common impulse is felt at the mid-to-lower left sternal edge. It reflects movement of the right ventricle and is due to hypertrophy and/or dilatation of this anteriorly located chamber. More rarely, a dilated pulmonary artery can be felt at the upper left sternal edge. This movement reflects either increased preload or increased afterload of that vessel and it only occurs during systolic expansion.
Significance
What is the significance of this rather unusual movement at the second interspace? Well, we're going to compare it again to the carotid impulse using the cotton swabs. The important point is look at the timing. It is in very early systole and it is non-sustained. Let's see that together, comparing the carotid to the impulse in the second interspace. [Cut-away]
Well, we really learned quite a bit from the evaluation of that movement at the second left interspace. To begin with, a little simple anatomy, the pulmonary artery sits below the second interspace. By all odds, this is an enlarged pulmonary artery. But, an additional pearl, that movement was non-sustained, it was dynamic in early systole. That suggests that the enlargement of that pulmonary artery may well be due to a volume, or preload, rather than a pressure load. It's a clue to a diagnosis.