In order to provide income over the lifetime of the retiree, the TDF is designed to increasingly invest in deferred annuities as the TDF reaches its target retirement date and investors in the TDF get older.
Freebase(0.00 / 0 votes)Rate this definition: Echocardiography. Echocardiogram, often referred to cardiac echo or simply an echo is a sonogram of the heart. Echocardiography uses standard two-dimensional, three-dimensional, and Doppler ultrasound to create images of the heart.
An echocardiogram (echo) is a test that uses high frequency sound waves (ultrasound) to make pictures of your heart.he test is also called echocardiography or diagnostic cardiac ultrasound. Quick facts. 1  An echo uses sound waves to create pictures of your heartâs chambers, valves, walls and the blood vessels (aorta, arteries, veins) attached to your heart. 2  A probe called a transducer is passed over your chest.