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Ausculation lower left sternal edge
Again, a remarkable amount of information to learn from listening at the lower left sternal edge, especially when we watch respiration. Let’s listen again together and watch respiration. [Cut-away] The most compelling single observation is that all the acoustic events get louder with inspiration, and that tells us something. That tells us that these events are right-sided. When one inspires, there is an accentuation of blood coming back to the right side and, hence, the murmurs get louder. Now, let’s dissect out, not just the fact they get louder during inspiration, meaning it’s right-sided, but what about the murmurs and sounds in systole and diastole? There is a loud systolic murmur. It’s typical of tricuspid regurgitation and confirms what we observed in the neck veins. In addition, there is a diastolic low frequency sound. First, an s3 and then a flow rumble. Don’t be fooled! Don’t think that that diastolic rumble is due to tricuspid stenosis. The s3 tells us it is from flow. If that valve were stenosed, how could we ever get enough blood gushing into the ventricle to generate the third heart sound? So, what we heard was (mimicking sound) and with inspiration (mimicking sounds), getting louder because it’s right-sided. Severe tricuspid regurgitation and the diastolic events really told us that the tricuspid regurgitation was severe. So much blood in that right atrium, that when it came across the valve again in diastole, it generated all that diastolic sound.
Oscilloscopic image
By viewing an oscilloscopic image and simultaneously listening, we can further appreciate these auscultatory events.