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.
Mitral regurgitation is leakage of blood backward through the mitral valve each time the left ventricle contracts. Aortic valve regurgitation may stem from a congenital heart defect, complications of an infection or other more rare causes.