Myocardial ischemia is a heart condition in which not enough blood supply and oxygen reaches
the heart muscle. Damage to the major blood vessels of the heart (coronary artery disease),
minor blood vessels of the heart (microvascular heart disease), or damage to the heart
muscle (hypertrophic cardiomyopathy) can cause myocardial ischemia. Any of theses three
conditions can cause patients to experience chest pain and other symptoms as well as cause
the heart to function improperly.
In order to detect myocardial ischemia researchers can use tests to measure the movement of
the walls of the heart. Walls receiving inadequate supplies of blood often move less and
occasionally move in the opposite direction. Some of the tests may require patients to
receive injections of radioactive tracers. The radioactive material acts to enhance 3
dimensional pictures of the heart and helps to identify areas of ischemia.
The purpose of this study is to determine whether 3-dimensional imaging (tomography) with
radioactive tracers can provide more important information about heart wall function than
routine diagnostic tests.
We propose to assess regional myocardial function using gated blood pool imaging acquired by
a tomographic technique at rest and during stress in patients with myocardial ischemia
(coronary artery disease, hypertrophic cardiomyopathy and microvascular angina). Gender
differences in response to exercise and pharmacologic stress will also be evaluated. Normal
subjects will be studied in order to establish a control database. Current methods of gated
blood pool studies use planar imaging, with its attendant limitations; poor resolution and
inadequate separation of the myocardial segments, only one view assessed during exercise and
superimposition of overlying structures. Tomographic imaging has the advantages of
reconstructing 3-dimensional data of the entire heart with the ability to improve segmental
resolution and separate overlapping structures, potentially resulting in increased
sensitivity and specificity for detection of disease.
The role of pharmacologic stress will be assessed by comparison with exercise stress, in
order to validate its use in subjects unable to exercise and identify gender related
differences. Quantitative measures of regional wall motion obtained from tomography will be
compared to regions of prior myocardial infarction (if present), and with other modalities
for evaluating cardiac structure and function. The diagnostic and prognostic value of
tomographic wall motion analysis will be studied in patients with myocardial ischemia, with
special emphasis on correlation between physiologic variables of coronary blood flow and
Patients with known coronary artery disease (obstruction of greater than or equal to 50%
in at least one major coronary artery).
Patients with hypertrophic cardiomyopathy.
Patients with microvascular angina.
No unstable angina.
No hepatic or renal failure.
No primary valvular disease.
No congenital heart disease.
No pregnant or breast feeding women.