A pericardial friction rub is a scratching, grating, or crunching sound produced when inflamed layers of the pericardium slide over one another. It ranges from faint to loud and is best heard along the lower left sternal border during deep inspiration. This finding indicates pericarditis, which may result from infection, cardiac or renal disorders, postpericardiotomy syndrome, or certain medications.

The classic rub is triphasic, corresponding to atrial systole, ventricular systole, and early ventricular diastole. Occasionally, it may appear biphasic or monophasic, and can be confused with a murmur or pleural friction rub.

History and Physical Examination

History

• Determine recent cardiac events: myocardial infarction, cardiac surgery, or pericarditis.

• Ask about rheumatic or autoimmune disorders: rheumatoid arthritis, systemic lupus erythematosus.

• Assess for chronic renal failure or systemic infections.

• Explore chest pain: character, location, triggers, relieving and aggravating factors.

• Review medications known to induce pericarditis (e.g., procainamide, chemotherapeutic drugs).

Physical Examination

• Take vital signs: blood pressure, pulse, respiratory rate, temperature; note hypotension, tachycardia, tachypnea, or fever.

• Inspect for jugular vein distention, peripheral edema, ascites, and hepatomegaly.

• Auscultate lungs for crackles; auscultate the heart carefully to detect rubs, murmurs, or other abnormal sounds.

Exam Tips: Differentiating from Murmurs

• Depth: Friction rub sounds superficial; murmurs are deeper.

• Radiation: Friction rub usually does not radiate; murmurs may.

• Variation: Friction rub varies with inspiration; murmurs less so.

Understanding Pericardial Friction Rubs

• Triphasic rub: Presystolic (atrial systole), systolic (ventricular contraction), early diastolic (ventricular filling).

• Biphasic rub: Presystolic and early diastolic components merge.

• Monophasic rub: Usually occurs during ventricular systole.

Medical causes

Special considerations

• Monitor cardiovascular status; disappearance of rub may indicate cardiac tamponade.

• Watch for pallor, hypotension, tachycardia, tachypnea, paradoxical pulse, and jugular vein distention.

• Provide rest and treat underlying cause with anti-inflammatories, antiarrhythmics, diuretics, or antimicrobials.

• Prepare for pericardiocentesis or pericardiectomy if cardiac output is compromised.

Patient counseling

• Explain pericarditis, its causes, and treatments.

• Teach measures to minimize symptoms, including rest and medication adherence.

• Advise prompt reporting of worsening chest pain, dyspnea, or fainting episodes.

Pediatric pointers

• Bacterial pericarditis can occur in children, usually <6 years old.

• Pericardial rub may occur post-surgery for congenital cardiac defects but often resolves without pericarditis.

• Other signs: fever, tachycardia, dyspnea, chest pain, jugular vein distention, hepatomegaly.

References

• Buttaro, T. M., Tybulski, J., Bailey, P. P., & Sandberg-Cook, J. (2008). Primary Care: A Collaborative Practice (pp. 444–447). St. Louis, MO: Mosby Elsevier.

• McCance, K. L., Huether, S. E., Brashers, V. L., & Rote, N. S. (2010). Pathophysiology: The Biologic Basis for Disease in Adults and Children. Maryland Heights, MO: Mosby Elsevier.

• Sommers, M. S., & Brunner, L. S. (2012). Pocket Diseases. Philadelphia, PA: F.A. Davis.