'''Central venous pressure (CVP), also known as mean venous pressure' (MVP) is the pressure of blood in the thoracic vena cava, near the right atrium of the heart. CVP reflects the amount of blood returning to the heart and the ability of the heart to pump the blood into the arterial system. CVP is often a good approximation of right atrial pressure (RAP), however the two terms are not identical, as right atrial pressure is the pressure in the right atrium. CVP and RAP can differ when arterial tone is altered. This can be graphically depicted as changes in the slope of the venous return plotted against right atrial pressure (where central venous pressure increases, but right atrial pressure stays the same; VR = CVP-RAP).