Describe Pericardial Rub and their Characteristic ?

Generation of sound: The sound is generated due to rubbing of visceral and parietal pericardial surfaces against each other. In case rub is suspected but not heard in supine position, the following technique can be used. Apply the stethoscope firmly to precordium while the patient rests on elbows and knees (as the opposition of two layers of pericardium is better).

Characteristic: Superficial, scratchy, leathery sound component. In sinus rhythms, the typical rub is three phased (one systolic and two diastolic).
Mid systolic
1.) Diastolic
2.) Pre systolic
The mid systolic phase is most consistent followed by the presystolic phase (disappears in atrial fibrillation).
Most likely causes of pericardial friction rules are Rheumatic, Pericarditis, tuberculosis, Pericarditis.
Immediately post open heart surgery

• MI
• Uremia.

It can often be heard posterior over the back.