This study will examine heart function using two imaging techniques - echocardiography (ultrasound) and magnetic resonance imaging (MRI) - to evaluate newly developed software for echocardiograph machines. MRI and ultrasound both provide images of the heart structure and function. MRI uses a magnetic field and radio waves to obtain the pictures, while echocardiography uses sound waves.

Patients with any form of heart disease and healthy volunteers 21 years of age and older may be eligible for this study. Candidates must be and able to undergo magnetic resonance imaging and must not have an irregular heart rhythm, heart valve disease, a pacemaker, defibrillator implant, insulin pump, or other metallic implant.

Participants will have two ultrasound examinations and two magnetic resonance imaging examinations, as described below. All the tests will be completed within 24 to 48 hours.

Echocardiography :

For this test, a small probe is passed over the chest. Sound waves emitted from the probe bounce off the heart and are beamed back into the echo machine where they are recorded. The sonographer does a baseline test, which is evaluated by the physician. Then, after a 10- to 20-minute break, portions of the test are repeated. The entire exam takes about 2 hours.

Magnetic Resonance Imaging:

For MRI, the subject lies on a table that slides into a long doughnut-shaped scanner. A small tube is placed in a vein in the hand or arm to give fluids and to infuse gadolinium, a contrast material that brightens the images.

Heart rate and blood pressure are monitored during the study, which takes about 3 hours.