This study is being done with a radioisotope, 123I-mIBG (Adreview), to develop a nuclear
diagnostic imaging test for patients with decreased heart function which can be used to
predict the progression of the heart disease and provide the appropriate clinical treatment.
The types of patients to be studied include patients who have had a heart attack where heart
muscle may be damaged and patients diagnosed with heart failure who have enlarged hearts.
Both conditions may cause poor muscle contraction and disturbances in electrical signal
conduction. There will also be a control group of participants with no evidence of heart
disease.
123I-mIBG has been shown to be effective in assessing the areas of the heart being activated
involuntarily by the sympathetic nervous system (SNS). 123I-mIBG is an iodine based
radioisotope that is chemically similar to norepinephrine (NE) in the heart. NE is
responsible for the way the SNS regulates heart functions such as heart rate and the force of
heart contractions. NE acts automatically to maintain a homeostasis or balance within the
SNS. The amount of 123I-mIBG, mimicking NE, that appears on the nuclear image using the
heart-to-mediastinum ratio (H/M ratio), was predictive of the progression of heart failure,
arrhythmias (irregular heartbeats) and cardiac death.
Two different types of single photon emission computed tomography (SPECT) imaging will be
used: standard SPECT and cadmium-zinc-telluride (CZT) SPECT. The investigators hypothesize
that CZT SPECT will have greater H/M ratios than standard SPECT imaging.