The SI unit for pressure is the pascal (Pa), equal to one newton per square metre (N/m 2 or kgÂ·m â1 Â·s â2). This name for the unit was added in 1971; before that, pressure in SI was expressed simply in newtons per square metre.
A leaking mitral valve allows blood to flow in two directions during the contraction. Some blood flows from the ventricle through the aortic valve â as it should â and some blood flows back into the atrium. A leaking (or regurgitant) aortic valve allows blood to flow in two directions.
See a picture of mitral valve regurgitation . When the mitral valve is damaged-for example, by an infection-it may no longer close tightly. This lets blood leak backward, or regurgitate, into the upper chamber. Your heart has to work harder to pump this extra blood. Small leaks are usually not a problem.