Pericardial knock is seen in?

Pericardial knock- early diastolic sound ( earlier than S3 ) indicates decreased ventricular compliance due to an external force heard in patients with constrictive pericarditis S3 is an early diastolic sound due to rapid ventricular filling with a large volume of blood so occur in patients with hyperdynamic circulation example : pregnancy, anemia, A-V shunts and congestive hea failure S4 filling of ventricle against a stiff ventricle so the atria have to give a final kick at end of diastole to completely empty itself