Advanced Physical Diagnosis
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• 1st & 2nd Heart Sounds
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• Clicks and Snaps
• Murmurs
• Rubs
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[Skill Modules >> Heart Sounds & Murmurs >> Techniques ]

Techniques: Heart Sounds & Murmurs

Rubs

The sounds of pleural and pericardial friction rubs are often mistaken for coarse crackles. Correct identification of pleural versus pericardial friction rubs is important in expanding diagnoses.
Pericardial Friction Rubs
Ausculatory sound:

Pericardial friction rubs are characterized by.

  • One systolic sound and two diastolic sounds (3 component rub) (systolic sound between S1 and S2)
  • One diastolic sound in early diastole and one at end diastole (2 component rub)
Site:

Over pericardium, often loudest at LLSB

Sound farther from chest wall

Rub often transient

Note: many patients with a pericardial friction rub also have a tachycardia
Respiratory variation: Tends to be louder during inspiration, also can sometimes better detect during forced expiration with the patient leaning forward
Sound characteristics:

High frequency
(hear best with diaphragm of stethoscope)

Scratchy, grating or squeaking

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Pleural versus Pericardial Friction Rub:
Pleural Pericardial
Auscultatory sounds:

One sound on inspiration and one sound on expiration
(expiratory sound may be absent)

 One systolic sound and two diastolic sounds
(systolic sound between S1 and S2)
(one diastolic sound in early diastole and one at end diastole)
(sounds are independent of respiration)
(pleural) (pericardial)
Site:
Over lower anterolateral chest (left or right) Over pericardium, often loudest at LLSB
Sound superficial; close to chest wall Sound farther from chest wall
Rub often transient

Rub often transient

Note: many patients with a pericardial friction rub also have a tachycardia
Respiratory variation:
Sounds disappear if hold breath Tends to be louder during inspiration, also can sometimes better detect during forced expiration with the patient leaning forward
Sound characteristics (similar for both):
High frequency
(hear best with diaphragm of stethoscope)		 High frequency
(hear best with diaphragm of stethoscope)
Grating or creaking sound Scratchy, gratin or squeaking

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