Cardiac Exam II: Auscultation
Source: Suneel Dhand, MD, Attending Physician, Internal Medicine, Beth Israel Deaconess Medical Center
Proficiency in the use of a stethoscope to list…
1. Position the patient at 30-45 degrees.
2. Make sure the area being examined is exposed, and never auscultate through the gown.
3. Place the stethoscope in the defined anatomical landmarks (Figure 1). A good rule of thumb to find the second intercostal space is to locate the angle of Louis (manubriosternal joint), which is at this level. Palpate across and down with your fingers to locate the other intercostal spaces described.
Figure 1. Auscultation surface landmarks.
- Aortic area
- Place the diaphragm of the stethoscope at the 2nd intercostal space, right sternal edge. This is the anatomical landmark for the aortic valve.
- Listen for at least 5 sec for the second heart sound, which represents the aortic valve closing.
- Pulmonic area
- Place the diaphragm of the stethoscope at the 2nd intercostal space, left sternal edge. This is the anatomical landmark for the pulmonary valve.
- Listen for at least 5 sec for the second heart sound, which represents the pulmonary valve closing.
- Tricuspid area
- Place the diaphragm of the stethoscope at the 4th - 5th intercostal space, left sternal edge. This is the anatomical landmark for the tricuspid valve.
- Listen for at least 5 sec for the first heart sound, which represents the tricuspid valve closing.
- Mitral area
- Place the diaphragm of the stethoscope at the 5th intercostal space, mid-clavicular line (same area as the apex beat). This is the anatomical landmark for the mitral valve.
- Listen for at least 5 sec for the first heart sound, which represents the mitral valve closing.
4. Other auscultation areas:
Auscultation of the lungs and major arteries also provides essential information of the function of the cardiovascular system.
- Auscultate with the diaphragm of the stethoscope at the bases of the lungs. Listen for any crepitations or crackles, which indicate fluid in the lungs (pulmonary edema), a sign of heart failure.
- Auscultate with the bell of the stethoscope at the carotid arteries. Frequently, a murmur that is present from the aortic valve may be heard. Also, auscultate here for a bruit (a swishing sound produced by turbulent blood flow), which is a sign of carotid artery stenosis.
- Auscultate for abdominal bruits at the renal arteries and femoral arteries to assess for peripheral vascular disease.
Proficiency in the use of a stethoscope to listen to heart sounds and the ability to differentiate between normal and abnormal heart sounds are essential skills for any physician.
The heart has two main sounds, S1 and S2. The first sound - S1- occurs as the mitral and tricuspid valves close, after blood enters the ventricles. This represents the start of a systole. The second heart sound - S2 - occurs when the aortic and pulmonary valves close, after blood has left the ventricles to enter the systemic and pulmonary circulation systems at the end of a systole. Together, they sound as "lub-dub"? "lub-dub".
In this video, we'll first review the surface landmarks for auscultation, and then we'll go through the essential steps for this exam. The discussion related to the abnormal heart sounds such as murmurs and gallops will be covered in a separate video of this collection.
Let's begin by reviewing the surface landmarks for auscultation. As discussed,
The aortic area corresponding to the aortic valve is along right sternal edge of the 2nd intercostal space, abbreviated as the 2nd ICS. Similarly, at the left sternal edge of the same ICS is the pulmonic area associated with the pulmonic valve. Travelling down the left sternal edge, in the 4th or 5th ICS is the tricuspid area corresponding to the tricuspid valve. And in the 5th ICS along the mid-clavicular line is the mitral area linked to the mitral valve.
Now that you're familiar with the landmarks, let's review the sequence of steps for this exam. Before starting the procedure wash your hands thoroughly and make sure that the stethoscope has been cleaned with a disinfectant wipe.
First, familiarize yourself with the stethoscope chest piece. The auscultation of the heart is performed using both - the diaphragm and the bell. The diaphragm is best for high frequency sounds, such as S1 and S2. The bell best transmits low frequency sounds, such as S3 and S4.
Begin by ensuring that the area to be examined is exposed, and request the patient to lie down at a 30-45? degree angle on the exam table. Before placing the stethoscope, a good rule of thumb is to locate the 2nd ICS by palpating for the Angle of Louis, which is at the level of the 2nd ICS. Next, place the diaphragm at the right sternal edge of this ICS, which is the aortic area. Listen at each auscultation spot for at least 5 seconds to ensure that you're not missing any subtle sounds. In addition, throughout the exam ask the patient to breathe in and out, because in presence of an abnormal sound, the timing in the respiratory cycle can provide a vital diagnostic clue. While auscultating the aortic area, listen for S2, which represents the aortic valve closing. Next, move to the pulmonic area, which is on the left sternal edge of the 2nd ICS. Here, again you can clearly distinguish the second heart sound, which represents the pulmonic valve closure. Subsequently, using the diaphragm, auscultate the tricuspid area at the 4th or 5th ICS on the left sternal edge. Here, listen for the first heart sound due to the tricuspid valve closing. Lastly, place the diaphragm in the mitral area and listen for S1, which represents the mitral valve closure.
In addition to the four valve-associated landmarks, auscultation of the lungs and major arteries can provide essential information regarding the cardiovascular functioning. Using the diaphragm, auscultate at the base of the lungs to listen for any crepitations or crackles, which indicate pulmonary edema, a sign of heart failure. Next, with the bell, auscultate the carotid arteries. Frequently, a murmur that is present from the aortic valve may be heard in this area. Also, auscultate here for a bruit, which is a swishing sound produced by turbulent blood flow, a sign of carotid artery stenosis. Finally, to assess for peripheral vascular disease, auscultate for abdominal bruits at the aorta area, renal arteries, and femoral arteries.
You've just watched JoVE's presentation on cardiac auscultation. The video reviewed important auscultation landmarks and illustrated how to perform the steps of this exam in a structured fashion.
Auscultation of the heart remains one of the fundamental skills for any clinician to master, and it provides vital diagnostic clues to many cardiac abnormalities. Therefore, learning the correct technique for auscultation is essential in order to be able to distinguish normal from pathological. As always, thanks for watching!
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Q1: What are the two main heart sounds and when do they occur?
The heart produces two main sounds: S1 and S2. S1 occurs when the mitral and tricuspid valves close after blood enters the ventricles, marking the start of systole. S2 occurs when the aortic and pulmonary valves close after blood leaves the ventricles, marking the end of systole. Together, they create the characteristic "lub-dub" sound.
Q2: Where should you place the stethoscope to listen to each cardiac valve?
The aortic valve is auscultated at the right sternal edge of the 2nd intercostal space. The pulmonic valve is at the left sternal edge of the 2nd intercostal space. The tricuspid valve is at the left sternal edge of the 4th or 5th intercostal space. The mitral valve is located at the 5th intercostal space along the mid-clavicular line.
Q3: Why should you use both the diaphragm and bell of the stethoscope during cardiac auscultation?
The diaphragm is best for high-frequency sounds like S1 and S2, and should be pressed firmly against the chest wall. The bell best transmits low-frequency sounds like S3 and S4, and should be applied with light pressure. Using both components allows you to detect the full range of cardiac sounds and potential abnormalities.
Q4: How do you locate the correct anatomical landmarks before beginning cardiac auscultation?
Begin by palpating for the Angle of Louis, which marks the level of the 2nd intercostal space. This bony landmark serves as your reference point for identifying all four valve auscultation areas. Once you locate the 2nd intercostal space, you can systematically move to the other valve locations using the anatomical relationships described for each area.
Q5: What additional areas should you auscultate beyond the four cardiac valve sites?
Beyond the valve areas, auscultate the base of the lungs using the diaphragm to detect crepitations or crackles indicating pulmonary edema. With the bell, auscultate the carotid arteries for murmurs or bruits from turbulent blood flow. Finally, assess for peripheral vascular disease by auscultating for abdominal bruits at the aorta, renal arteries, and femoral arteries.
Q6: What preparation steps are essential before performing cardiac auscultation?
Wash your hands thoroughly and clean the stethoscope with a disinfectant wipe. Familiarize yourself with the stethoscope chest piece components. Ensure the patient's chest is exposed and position them at a 30-45 degree angle on the exam table. Listen at each auscultation spot for at least 5 seconds and ask the patient to breathe in and out throughout the exam.
Q7: Why is listening to respiratory patterns important during cardiac auscultation?
Throughout the exam, ask the patient to breathe in and out because the timing of abnormal sounds within the respiratory cycle provides vital diagnostic clues. Changes in heart sounds or the appearance of murmurs during specific phases of breathing can help identify the underlying cardiac pathology and guide further clinical assessment.