Pericardial rub is produced due to the sliding of the two inflamed layers of the pericardium.
Features of pericardial rub
- Site -Left sternal border 3rd and 4th intercostal space usually best heard on the left side of lower sternum may be heard over the entire precordium
- This is triphasic with midsysiolic middiastolic and presystolic components.
- They are evanescent and they may vary with time and posture.
- Creaky/leathery ,scratching, grating or creaking in character and mimics the sound produced from husking machine
- Intensity of the sound increases when patient sits and leans forward (thus, always auscultate in sitting and leaning position of the patient).
- Sound increases by pressing the chest piece (diaphragm) of stethoscope.
- Sound continues even after holding the breath.
- It may be associated with chest pain.
- Usually there is no transmission that is localised
Cause of pericardial rub
- Pericarditis and pericardial effusion
- Viral pericarditis
- Pyogenic pericarditis
- Tuberculous pericarditis
- Acute myocardial infarction
- Dressler's syndrome
- Acute rheumatic fever
- SLE
- Rheumatoid arthritis
- Uremia.
Pericardial rub persist inspite of the effusion unlike in pleural effusion, because both layers of the pericardium dip deep into the AV groove which cannot be separated by the fluid in pericardial effusion thus the rub is persisting.
In acute Myocardial infarction, pericardial rub indicates transmural infarction.
Differential diagnosis of pericardial rub
- Systolic murmur.
- Early diastolic murmur of aortic incompetence.
- Continuous murmur.
- Artefact.
- Hamman's sign.
