Diagnostic Three Dimensional Echocardiography Study Protocol

The purpose of this study is to perform ground-based research to study what happens to the heart muscle in space. People who have problems with their aortic valve have an increase in the amount of muscle in the left ventricle of the heart. After valve surgery, the amount of muscle should decrease and return to normal. Astronauts lose heart muscle mass during space flight. Our study will look at these changes in your heart, which we believe are similar to what happens during long term space travel. This study will look at the accuracy of three dimensional ultrasound imaging (echo) in monitoring the changes in heart size and function following aortic valve replacement. We are studying ways to prevent health-related problems that men and women will face on long-duration space missions. The hypothesis is that serial two dimensional and three dimensional echo will show accurate changes in the left ventricle mass and volume following aortic valve replacement for aortic stenosis or regurgitation