Can pericardial rub be heard on a heart echo?

Yes: Pericardial friction rubs are notoriously ephemeral; one physician will hear it and it's gone by the time the next physician listens. This is to be expected since there must be exactly the right amount of fluid for the two layers to rub each other and make a sound. Echo answers a deeper question -- is there inflammatory fluid in the pericardial sack?

Pericardial rub: That is heard with a stethoscope.