Cardiac auscultation refers to listening to the sounds of the heart with a stethoscope. This short, yet important part of a health exam can tell a lot about the patient’s well-being.
To listen to the different points of auscultation, the doctor will use either a traditional or tunable stethoscope to determine if there are any abnormalities present and if further tests need to be performed. Stethoscope types should be chosen with consideration to the doctor’s needs and the type of patients they will be working with.
Typically, the heart creates a “lub-dub” sound, which occurs when blood is being pumped and flowed to and from the heart. These are also referred to as S1 and S2 sounds.
The S1 sound is caused by the closure of the mitral and tricuspid valves. The S2 sound follows, caused by the closure of the aortic and pulmonic valves.
The aortic point is located on the right side of the sternum in the second intercostal space. This is where the doctor will place the stethoscope to listen to the sounds produced by the aortic valve. Here the heart produces the S2 sound, which your doctor will listen for.
The pulmonic point is left to the sternum in the second intercostal space.
The typical S2 sound, referred to as the “dub” sound, should also be present at the pulmonic auscultation point.
Erb’s point is located to the left of the sternum in the third intercostal space and is the approximate center of the heart.
At this point, the doctor will listen for both the S1 and S2 sounds.
The tricuspid point is left of the sternum in the fourth intercostal space. The tricuspid valve assists blood flow in the right direction while separating the upper and lower chambers of the heart.
Here your doctor can listen to the S1, or “lub”, sound. They can also check for an opening snap, which is a high-frequency sound caused by the opening of the mitral or tricuspid valves, which may indicate a narrowing of the valves.
The mitral point is located at the left side of the sternum in the fifth intercostal space.
Here, your doctor will get the clearest resonance of the S1 sound.
Many stethoscopes now offer tunable diaphragm technology. This helps make finding and listening to auscultation points easier and clearer.
To use, the doctor needs to adjust the pressure applied from the hand to the area of the chest. Light pressure helps with hearing lower frequency sounds, while firm pressure blocks the low sounds and amplifies the higher frequency sounds.
Traditional stethoscope models, which are often used on children, require the doctor to turn over and reposition the chest piece to listen to the different auscultation points. They will first use the flat diaphragm side, followed by the concave bell side.
When the stethoscope is used by a medical professional, it can amplify important cardiac sounds to help determine whether patients may have certain murmurs, heart valve dysfunction, or other abnormalities that require further investigation.