This study is designed to use PET scans in order to measure activity of the sympathetic
nervous system. The sympathetic nervous system is the portion of the nervous system that
maintains a normal supply of blood and fuel to organs during stressful situations.
PET scan or Positron Emission Tomography is an advanced form of an X-ray. It is used to
detect radioactive substances in the body. During this study researchers plan to inject
small amounts of the radioactive drug fluorodopamine into patients. Fluorodopamine is very
similar to the chemicals found in the sympathetic nervous system. It can attach to
sympathetic nerve endings and allow researchers to view them with the aid of a PET scan.
One area of the body with many sympathetic nerve endings is the heart. After giving a dose
of fluorodopamine, researchers will be able to visualize all of the sympathetic nerve
endings involved in the activity of the heart. In addition, this diagnostic test will help
researchers detect abnormalities of the nervous system of patient's hearts.
This project applies positron emission tomographic (PET) scanning after administration of
6-[18F]fluorodopamine ([18F]-6F-DA) to visualize sympathetic innervation and function in
patients with neurocardiologic disorders. Patients undergo infusion of [18F]-6F-DA,
followed by PET scanning of one or more body regions. Patients may also undergo PET
scanning after administration of [13N]-ammonia, to assess regional perfusion; regional blood
sampling (including sampling from the coronary sinus or great cardiac vein) during infusion
of [3H]-l-norepinephrine ([3H]-NE), to assess the kinetics and metabolism of NE; or
magnetic resonance imaging (MRI) to delineate the ventricular myocardium. PET scanning
after [18F]-6F-DA administration, in conjunction with other clinical assessment tools,
should provide comprehensive information about regional sympathoneural innervation and
function in neurocardiologic disorders.
The subjects are adult patients in one of the following diagnostic categories: coronary
heart disease or chest pain and normal coronary arteries; myocardial dysfunction or
failure; hypertension; or dysautonomia. Groups of appropriately matched healthy
volunteers are studied concurrently as controls.
Minors are excluded.
Subjects in whom anatomic factors complicate vascular access are excluded.
Subjects who are not expected clinically to tolerate recumbency during the procedures are
Pregnant or lactating women are excluded.
Cardiology patients may be tested while off their usual medications. In this situation,
the patients will be inpatients on the cardiology ward, managed clinically by staff of the
Cardiology Branch, DIR, NHLBI. Hypertensives will be tested afer having discontinued
anti-hypertensive medications for up to two weeks.
Patients who must take medications continually in the following categories are excluded:
anticoagulants, tricyclic antidepressants, barbiturates, aspirin, acetaminophen.
Patients unable to discontinue nicotine or alcohol temporarily are excluded.