All Direct Subsidized and Unsubsidized Loans disbursed between July 1, 2014 and June 30, 2015 carry a fixed interest rate of 4.66% for undergraduates. Graduate or professional students receiving a Direct Unsubsidized Loan disbursed between July 1, 2014 and June 30, 2015 will have a fixed interest rate of 6.21%.
There is a problem when the valve that controls what blood is good and what blood is used, no longer is strong enough to control this flow. Heart valves get damaged or simply wear out. I think you are asking what causes blood to flow in the wrong direction. My guess is that it would be a faulty heart valve.
Narrowing of the Arteries. Coronary arteries transport blood to your heart muscle. When high blood pressure causes the blood vessels to become narrow, blood flow to the heart can slow or stop. This condition is known as coronary heart disease (CHD), also called coronary artery disease. CHD makes it difficult for your heart to function and supply the rest of your organs with blood.