What is the difference between paradoxical septal wall motion and septal bounce in the context of cardiac (heart) function?

Paradoxical septal wall motion and septal bounce are distinct cardiac wall motion abnormalities with different causes and clinical implications. Paradoxical septal wall motion refers to the abnormal movement of the interventricular septum toward the right ventricle during systole (instead of the normal leftward movement), commonly seen after cardiac surgery, in left bundle branch block, or with right ventricular volume overload. This occurs because of altered electrical activation or mechanical forces acting on the septum. Septal bounce, on the other hand, is a characteristic back-and-forth movement of the interventricular septum during early diastole, typically observed in constrictive pericarditis. It results from the sudden shift in transseptal pressure gradient during early diastole when ventricular filling is constrained by the rigid pericardium. While paradoxical septal motion primarily affects systole and may not necessarily indicate pathology (especially post-cardiac surgery), septal bounce is a diastolic phenomenon that strongly suggests constrictive pericarditis and warrants further evaluation with additional imaging and hemodynamic studies to confirm the diagnosis.