Let us now analyze the contour of this inferolaterally displaced, dilated left ventricle. I can put light pressure on the chest wall and i feel two impulses. Now, to make that point, to exaggerate it, to appreciate it better, let’s put the cotton swab on the chest wall and we can clearly see two impulses. [cut-away] but then we have to ask: what is the timing of those impulses? And it’s so simple to use the carotid vessel, and we define the fact that there is a sustained systolic impulse at the apex, timed in systole, of course, therefore, with the carotid, and an early diastolic movement as well. Let’s analyze them and explain them one at a time.

The sustained apical impulse? Well, that suggests that this, yes, dilated left ventricle also has an element of hypertrophy, which is often the case. And the early diastolic movement? Well, that could be due to one of two possibilities: first, a poorly contractile left ventricle, a failing ventricle. You can have an s3 as blood goes across that mitral valve into the ventricle, it decelerates because the ventricle is stiffened, and you generate that low frequency sound that, yes, can be felt. Or, alternatively, it might be due to excess flow across that mitral valve into the ventricle, it decelerates and you generate third sound from flow alone, sometimes seen in mitral regurgitation, sometimes seen in shunt lesions. We have two different possibilities for that s3 we can palpate. On occasion, not in this case, where it is so readily felt, you roll that patient over in the left lateral decubitus position, and you can really feel subtle apical impulses that give you so much information.