What is the effect on tricuspid valve (TV) inflow during inspiration in cases of cardiac tamponade?

During inspiration, the negative intrathoracic pressure increases venous return to the heart, which typically enhances the filling of the right atrium and subsequently increases blood flow across the tricuspid valve. In cases of cardiac tamponade, while you may expect some alterations due to the restrictive effects of the accumulated fluid, the fundamental physiological response remains. During inspiration, the augmented venous return can still lead to an increased inflow through the tricuspid valve, despite the underlying hemodynamic compromise caused by the tamponade.

The phenomenon described is also influenced by the concept of pulsus paradoxus, where the normal variation in stroke volume and blood flow dynamics may be exaggerated in the setting of tamponade. However, the general response during inspiration leads to increased flow through the tricuspid valve due to the mechanics of venous return and right heart filling pressure.