Ventricular interdependence occurs when there is discordance. This results from the heart ventricles filling out of phase with one another. It is an important physiological manifestation of cardiac tamponade and constrictive pericarditis.
The ventricles experience impaired diastolic relaxation secondary the constrictive pericardium and are unable to fully expand. During inspiration, the right ventricle will fill and shift the interventricular septum to the left reducing its filling capacity. During expiration, the opposite will occur with the interventricular septum moving to the right.
Santamore WP, Dell’Italia LJ. Ventricular interdependence: significant left ventricular contributions to right ventricular systolic function. Prog Cardiovasc Dis. 1998 Jan-Feb;40(4):289-308.