Learning points:
1. Kussmaul’s sign refers to a jugular venous pulsation that rises with inspiration and is due to the constriction of pericardium

2. Ventricular interdependence is the classic echo finding of constrictive pericarditis where the volume in the left heart is dependent on the volume in the right heart

3. Constrictive cardiomyopathy often has both systolic and diastolic dysfunction with normal BNP while restrictive cardiomyopathy is pure diastolic dysfunction and elevation of BNP.

4. Click below for a great review from NEJM: