Heart Disease in Sickle Cell Anemia

This study will explore what may cause people with sickle cell anemia to have heart problems and an increased risk of sudden death. People 18 years of age and older with sickle cell anemia may be eligible for this study. Candidates are screened with a medical history and physical examination, electrocardiogram (EKG), echocardiogram (heart ultrasound), and blood tests. Participants undergo the following tests and procedures:

• Holter monitoring: The patient wears a small, battery-operated device to record heart rate and rhythm over 24 to 48 hours.
• QRST surface mapping: An EKG using 64 electrodes is done at rest and during exercise to provide a detailed look at the heart and its conduction system.
• Chest x-rays are taken to examine the lungs.
• Bicycle exercise echocardiography test: Blood pressure, pulse, heart rhythm and oxygen use are monitored while the patient exercises on a stationary bicycle. Ultrasound pictures are also obtained during the exercise.
• Echocardiogram: A heart ultrasound is done to check how well the heart is pumping blood.
• Pulmonary artery catheterization: A catheter (plastic tube) is inserted into a vein and advanced to the chambers of the heart, through the heart valve and into the lung artery. The pressures in the heart and lung blood vessels are measured while the patient is resting and during exercise, with the bed tilted up and down, and after giving 500 mls of fluid into a vein.
• Blood tests are done to measure a hormone called brain natriuretic peptide, which can increase with the development of heart failure, and nitrite, a substance that can affect blood vessel dilation. Some blood is stored to test for inflammatory markers and for possible future gene and protein analysis.
• Cardiac magnetic resonance imaging (cMRI): The patient lies in a donut-shaped magnet while pictures of the heart are obtained using a magnetic field and radio waves. Earplugs are worn to muffle the loud sounds that occur with electrical switching of the magnetic fields. A contrast agent called gadolinium may be injected to enhance the quality of the images.
• Invasive electrocardiographic (reveal) monitoring: This procedure permits study of the heart rhythms over a long time period. A small device is placed just under the skin on the left side of the chest. It can be left in for up to 14 months to monitor the heartbeat continuously during this time.