From the Guidelines
The best position to auscultate a pericardial friction rub is with the patient leaning forward while sitting up and in full expiration. This position brings the heart closer to the chest wall and maximizes the contact between the inflamed pericardial surfaces, as suggested by the clinical presentation of pericarditis in patients, where chest pain is often sharp, pleuritic, and improved by sitting up or leaning forward 1. The examiner should use the diaphragm of the stethoscope and listen at the left lower sternal border or cardiac apex, applying firm pressure.
Pericardial friction rubs are high-pitched, scratchy, grating sounds that occur when inflamed pericardial surfaces rub against each other during cardiac movement. They typically have three components corresponding to atrial systole, ventricular systole, and ventricular diastole, though all three components may not always be present. Friction rubs are often transient and can change in intensity or disappear completely within hours, so repeated examinations may be necessary. Having the patient hold their breath during auscultation helps differentiate pericardial friction rubs from pleural rubs, as pericardial rubs continue during breath-holding while pleural rubs cease.
Some key points to consider when auscultating a pericardial friction rub include:
- Using the diaphragm of the stethoscope for better sound quality
- Listening at the left lower sternal border or cardiac apex for optimal sound transmission
- Applying firm pressure to ensure good contact between the stethoscope and the chest wall
- Having the patient hold their breath to differentiate pericardial from pleural rubs
- Recognizing that friction rubs can be transient and may require repeated examinations for detection, as pericarditis can present with a variety of symptoms and signs, including chest pain, fever, and malaise 1.
From the Research
Auscultation Position for Pericardial Friction Rub
- The best position to auscultate a pericardial friction rub is along the left sternal border, as reported in 2 where rubs were best heard in 84 percent of cases.
- Leaning forward and sitting up may also increase the likelihood of observing this physical finding, as suggested in 3.
- The rub tends to be louder during inspiration than during expiration, as noted in 2, although in some cases there may be no respiratory predilection.
Additional Factors Influencing Auscultation
- The position of the patient, such as the left lateral decubitus position, may affect the intensity of the pericardial friction rub, as seen in 4.
- Extension of the neck does not have a dependable effect on rub intensity, as reported in 2.
Clinical Presentation and Diagnosis
- A pericardial friction rub is a key physical finding in acute pericarditis, present in up to 85% of patients, as stated in 5.
- The rub is usually auscultated along the lower left sternal border, as mentioned in 6.
- Electrocardiographic changes, such as diffuse concave-upward ST-segment elevation, can aid in the diagnosis of acute pericarditis, as discussed in 6 and 5.