Quantitation of Cardiac Output Change by Impedance Cardiography in Subjects Undergoing Exercise Gated Stress/Rest Tc-99m CZT-SPECT MPI

Study Overview
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Brief Summary
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The aim of this study is to test for an early post-stress cardiac output (CO) change by impedance cardiography and its relation to the severity and extent of myocardial ischemia and angiographic coronary disease in subjects undergoing exercise stress testing using a novel cadmium-zinc-telluride (CZT) SPECT camera.

Detailed Description
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Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a well-established noninvasive procedure for the evaluation and risk stratification of patients with coronary artery disease (CAD) (1). However, it has been recognized that in certain patients SPECT MPI is unable to detect the presence of or underestimates the extent of CAD. The fact that moderate to severe perfusion defects are noted in less than half of the patients with significant left main disease (2) has stimulated studies to improve the diagnostic accuracy of SPECT MPI. Such studies have analyzed post-stress parameters such as left ventricular (LV) ejection fraction (EF) (3, 4), wall motion abnormalities (5) and transient LV dilation (6) with images acquired on conventional Anger cameras as long as 60 minutes after the stress tracer injection. Such delayed assessment may miss early ischemic stunning as a result of its transient nature. However, detection of an early post-stress decrease in cardiac output (CO) may serve as a potential marker for the presence of significant or extensive ischemia. The aim of this study is to test for an early post-stress CO change by impedance cardiography and its relation to the severity and extent of myocardial ischemia and angiographic coronary disease in subjects undergoing exercise stress testing using a novel cadmium-zinc-telluride (CZT) SPECT camera.

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Device: Single photon emission computed tomography myocardial perfusion imaging
* Other: exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients referred to the Nuclear Cardiology Center for a clinically indicated exercise stress MPI study Exclusion Criteria: known standard contraindications for ergometry anemia hyperthyroidism intra- and extra-cardiac shunts significant arrhythmia hemodialysis

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 79 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: NICAS<br>There is only one arm - a single cohort. All patients undergoing the nuclear stress test will also have the NICAS evaluation. | Device: Single photon emission computed tomography myocardial perfusion imaging<br>* a novel cadmium-zinc-telluride (CZT) SPECT camera<br>Other: exercise<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Ischemia | Inducible and reversible perfusion defects, representing myocardial ischemia | 15-20 minutes after stress test | 
| Cardiac Output | Noninvasive evaluation of cardiac output using a novel algorithm based on impedenace | 15-20 minutes after exercise test |