Auscultation at the Apex (Mitral Area)
My rationale for beginning at the mitral area is to compare the auscultatory findings with those previously obtained by percussion and palpation (see Nonauscultatory Cardiac Exam: Assessing the Elderly Person). Take a moment to focus on the heart sounds and to orient yourself to the cardiac cycle. This is the best place to hear S1, mitral valve murmurs, and S3 and S4 gallops. It is also useful to compare the quality of the sounds with the point of maximal impact (PMI) you palpated.
Listen to S1
Note especially the intensity of S1 relative to S2. Normally S1 is louder than S2 at the apex. The loudness of the mitral valve closure depends upon 3 things:
the degree of valve opening (whether it has had time to passively swing shut because of heart block),
the force of ventricular contraction shutting the valve, and
the integrity of the valve.
Think of a slamming door. The amount of its noise will depend on how far open the door is, how hard you slam it, and the integrity of the door.
Hearing a soft S1. S1 equal to or softer than S2 in the mitral area implies the following, from which you can often determine the likely mechanism:
First-degree AV block. Recheck the neck veins for distinct "a" and "c" waves, which reflect the PR interval on the EKG.
Left ventricular failure. Will show jugular venous distension, bibasilar rales, an S3 gallop, hepatomegaly, and pedal edema (consider myocardial infarction, ischemia, or ventricular aneurysm).
Left ventricular hypertrophy. Usually develops from chronic hypertension and characteristically produces an enlarged, displaced PMI.
Left bundle branch block. Produces a paradoxically split S2.
Significant mitral insufficiency.
Sometimes obesity and emphysema will also reduce the intensity of S1.
Hearing a loud S1. Hearing a very loud S1 suggests mitral stenosis, a hyperdynamic state (from fever, hyperthyroidism, or anemia), or an atrial myxoma (very rare).
Hearing a variable S1. Once you have appreciated the loudness of S1 compared with S2, note any beat-to-beat variation in the intensity of S1.
An irregularly irregular rhythm and a variable intensity of S1 suggests atrial fibrillation.
Decreasing intensity of S1 until a dropped beat suggests second-degree AV block Mobitz type I (Wenckebach). You may first appreciate a sense of grouped beats.
Hearing a regular bradycardia with a variable S1 suggests third-degree AV block.
Another cause of a variable S1 is ventricular tachycardia.
Hearing a split S1. Next, pay attention to whether S1 is single or double. Hearing a single sound is normal. Reduplication of S1 suggests a split S1, hearing an S4 gallop and S1, or hearing S1 and an early ejection click. A split S1 suggests right bundle branch block, which produces delayed closure of tricuspid valve. Listen for wide split S2 as well ( Table 1 ).
There are a few tricks to tell if the reduplicated first heart sound is really an S4 gallop and S1. An S4 is heard best over the ventricular chamber producing the sound, so it is not usually heard in the aortic or pulmonic areas. With the patient in the left lateral decubitus position, listen while you push your bell so that the skin is stretched and produces a diaphragm. An S4 should disappear or be significantly muffled. It will disappear during an extra systole. Also having the patient perform 3 sit-ups may accentuate an S4, which is usually not as crisp and high-pitched as an ejection click. Also, you may have been able to palpate the S4 during your cardiac palpation of the PMI.
S1 and an early ejection click can also cause a split-sounding S1. An ejection click is usually crisp and high-pitched. It will move closer to S1 when the patient is standing. You may hear a mitral valve prolapse murmur or other clicks as well.
Listen to S2
Hearing a split S2 here suggests an S3 gallop or a wide split S2 with loud P2 or S2 and an opening snap.
An S3 gallop is caused by impaired ventricular compliance in early diastole. It suggests congestive heart failure until proven otherwise and can be accentuated with mild exercise, such as having the patient perform 2 or 3 sit-ups.
Listen to Systole (the Time Interval Coincident With the Pulse)
A murmur heard here suggests mitral regurgitation, mitral prolapse, tricuspid regurgitation, or ventricular septal defect (radiates to back, to left paravertebral area). Hearing an extra sound during systole at this location suggests an ejection click, the click of mitral valve prolapse, or a pericardial friction rub.
Listen to Early Diastole
Hearing an extra sound most commonly suggests an S3 gallop. The gallop is produced by decreased ventricular compliance and implies a low-ejection fraction. It is a key finding of congestive heart failure. Other conditions that can produce an S3 include mitral regurgitation, tricuspid regurgitation, cardiomyopathy, and right ventricular myocardial infarction.
Less common sounds in early diastole are the opening snap of mitral stenosis, a pericardial knock, an atrial myxoma tumor plop, and the beginning of a mitral stenosis murmur.
Listen to Late Diastole
An extra sound in late diastole suggests an S4 gallop. The S4 is produced by decreased ventricular compliance when ventricle is full. It is usually normal in very elderly people. If the S4 is palpable as well as audible, consider hypertension, pulmonary hypertension, and cardiac ischemia.
Medscape Family Medicine © 2012
Cite this: Mark E. Williams. Cardiac Auscultation in the Older Adult - Medscape - Jan 18, 2012.