When is the pericardial friction rub best heard in pericarditis?

When the Pericardial Friction Rub is Best Heard

The pericardial friction rub is best heard with the patient sitting upright and leaning forward while briefly holding their breath. 1

Optimal Auscultation Technique

Patient Positioning

• Have the patient sit upright and lean forward to bring the heart closer to the anterior chest wall, which enhances detection of the friction rub 1
• Ask the patient to briefly hold their breath during auscultation to minimize interfering lung sounds 1
• The left lateral decubitus position may also accentuate the sound in some cases 2

Auscultation Location

• Listen at the left lower sternal border, which is the classic location for detecting pericardial friction rubs 3
• The rub may be audible across multiple precordial areas but is typically most prominent in this region 4

Clinical Characteristics and Detection Challenges

Nature of the Friction Rub

• The sound is described as "sandpaper-scratching" in quality and is highly specific for pericarditis when present 2
• It is a transient finding that can disappear and reappear during the course of illness, making repeated examinations necessary 1
• The friction rub is present in only 18% to 84% of patients with acute pericarditis (most commonly cited as approximately one-third of cases), so its absence does not exclude the diagnosis 1, 5, 6

Common Pitfalls to Avoid

• Do not rely on a single examination: The friction rub can be intermittent, so multiple auscultatory examinations throughout the day may be required to detect it 1
• Do not exclude pericarditis based on absence of a rub: While highly specific when present, the friction rub is only audible in less than one-third of confirmed pericarditis cases 4, 1
• The rub may be more pronounced when the patient is supine in some cases, though the sitting-leaning-forward position is generally optimal for detection 4

Integration with Other Diagnostic Findings

The friction rub should be considered alongside other diagnostic criteria for acute pericarditis, which requires at least two of the following four findings 5, 6:

• Sharp, pleuritic chest pain that worsens when supine and improves with sitting forward (present in ~90% of cases) 5
• Characteristic ECG changes with diffuse concave ST-segment elevation and PR depression (25-50% of cases) 5
• New or worsening pericardial effusion on echocardiography (~60% of cases) 5
• Pericardial friction rub (<30% of cases) 5