At the age of 10, his older brother (age 14) died as a result of a defective valve in his heart.

However, defective valves allow blood to flow backward and pool inside the vein.

Of course, some of us seem to be born with defective valves.

Approximately 500 people died when defective valves failed and, in 1994, the United States ruled against Pfizer for $200 million.

Causes include congenitally defective valves, thrombophlebitis, and pregnancy.

Primary varicose veins occur because of congenitally defective valves, or without a known cause.

A 30,000-gallon tank from Canadian Terra International began leaking vapor, possibly because of a defective valve.

Matthew had a defective pulmonary valve as well as several other problems.

On April 8, 2008, at the age of 82, he underwent surgery to replace a defective aortic valve.

These include imaging the action of the heart muscle, defective valves, and even tumors within the heart itself.