Overview. Auscultation of heart sounds and murmurs is a rewarding and important skill of physical examination that leads directly to several clinical diagnoses. In this section, you will learn the techniques for identifying S1 and S2, extra sounds in systole and diastole, and systolic and diastolic murmurs. Review the auscultatory areas on the next page with the following caveats: (1) some authorities discourage use of these names since murmurs of more than one origin may occur in a given area; and (2) these areas may not apply patients with dextrocardia or anomalies of the great vessels. Also, if the eart is enlarged or displaced, your pattern of auscultation should be altered accordingly.
listen to the heart with your stethoscope in the right 2nd interspace close to ie sternum, along the left sternal border in each interspace from the 2nd irough the 5th, and at the apex. Recall that the upper margins of the heart are sometimes termed the "base" of the heart. Some clinicians begin auscultation at the apex, others at the base. Either pattern is satisfactory. The room should be quiet. You should also listen in any area where you detect an abnormality and in areas adjacent to murmurs to determine where they are loudest and where they radiate.
Know your stethoscope! It is important to understand the uses of both the diaphragm and the bell.
■ The diaphragm. The diaphragm is better for picking up the relatively high-pitched sounds of S1 and S2, the murmurs of aortic and mitral regurgitation, and pericardial friction rubs. Listen throughout the precordium with the diaphragm, pressing it firmly against the chest.
■ The bell. The bell is more sensitive to the low-pitched sounds of S3 and S4 and the murmur of mitral stenosis. Apply the bell lightly, with just enough pressure to produce an air seal with its full rim. Use the bell at the apex, then move medially along the lower sternal border. Resting the heel of your hand on the chest like a fulcrum may help you to maintain light pressure.
Pressing the bell firmly on the chest makes it function more like the diaphragm by stretching the underlying skin. Low-pitched sounds such as S3 and S4 may disappear with this technique—an observation that may help to identify them. In contrast, high-pitched sounds such as a midsystolic click, an ejection sound, or an opening snap, will persist or get louder.
Listen to the entire precordium with the patient supine. For new patients H and patients needing a complete cardiac examination, use two other im-^ portant positions to listen for mitral stenosis and aortic regurgitation.
■ Ask the patient to roll partly onto the left side into the left lateral decubitus ~ position, bringing the left ventricle close to the chest wall. Place the bell J of your stethoscope lightly on the apical impulse.
Heart sounds and murmurs that originate in the four valves are illustrated in the diagram below. Pulmonic sounds are usually heard best in the 2nd and 3rd left interspaces, but may extend further.
This position accentuates or brings out a left-sided S3 and S4 and mitral murmurs, especially mitral stenosis. You may otherwise miss these important findings.
■ Ask the patient to sit up, lean forward, exhale completely, and stop breathing in expiration. Pressing the diaphragm of your stethoscope on the chest, listen along the left sternal border and at the apex, pausing periodically so the patient may breathe.
This position accentuates or brings out aortic murmurs. You may easily miss the soft diastolic murmur of aortic regurgitation unless you use this position.
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