Let us evaluate together what we heard at the upper left sternal edge. Again, firm pressure on the diaphragm, watching respiration and tuning in on the second heart sounds. [cut-away] what we heard was paradoxic splitting of the second heart soujnd. Instead of the normal inspiratory splitting [sounds], what we heard was splitting in expiration. As the patient breathes out, [sounds].

In the context of a patient with coronary artery disease, there are several explanations and they relate to two things primarily: 1) if you have and electrical delay to the left side of the heart, that is, as seen in left bundle branch block, then the aortic valve will close later than normal. Or, if you have significant left ventricular dysfunction, as with an aneurysm or marked ischemia and dyskinesis of the left ventricle, you may also have a delayed closure of the aortic valve, and when that occurs, during inspiration, the pulmonary valve normally is delayed, so the two sounds come together and you hear [sounds]. But then in expiration, the aortic valve stays delayed but the pulmonary valve comes in a bit earlier, therefore, you hear splitting in expiration. An example of what you can sometimes hear in a patient with coronary artery disease is a clue to the underlying pathophysiology.