Within the cardiac intensive care unit, prompt recognition of severe acute valvular lesions is essential because hemodynamic collapse can occur rapidly, especially when cardiac chambers have not had time for compensatory remodeling. Within this context, optimal medical management, considerations for temporary mechanical circulatory support and decisive treatments strategies are addressed. Fundamental concepts include an appreciation for how sudden changes in flow and pressure gradients between cardiac chambers can impact hemodynamic and echocardiographic findings differently compared to similarly severe chronic lesions, as well as understanding the main causes for decompensated heart failure and cardiogenic shock for each valvular abnormality.