Study to Develop a Non-invasive Marker for Monitoring Myocardial Fibrosis

HCM Population: Inclusion Criteria: * Diagnosis of HCM as defined as: Interventricular septal thickness greater than 12 mm on a 2D echocardiogram, or septal: posterior wall thickness as measured on parasternal long axis view of \>1.3 in the absence of secondary causes of cardiac hypertrophy such as aortic stenosis and systemic hypertension. Exclusion Criteria: * Concomitant diseases that can lead to myocardial hypertrophy including valvular heart disease and uncontrolled hypertension. If HCM is proven by either the presence of a family history of HCM or through genotyping, patients with controlled hypertension will not be excluded. * Documented coronary artery disease including a history of previous myocardial infarction or coronary intervention or revascularization. * Known diabetic cardiomyopathy. ACS Population: Inclusion Criteria: * Diagnosis of ACS, either NSTEMI as determined by positive myocardial markers or STEMI patients who have an onset of symptoms 12 hours or less before presentation and an ST-segment elevation of at least 1 mm in two or more contiguous limb leads or of at least 2 mm in two or more contiguous precordial leads during prehospital 12-lead ECGs. Patients will undergo 99mTc-NC100692 imaging within 1 week of acute myocardial infarction. Exclusion Criteria: * Patients presenting with an acute STEMI secondary to an occlusive thrombus who were revascularized with coronary artery bypass surgery. * Patients with a known prior history of cardiomyopathy of any cause (ex. ischemic, hypertrophic, infiltrative, idiopathic dilated), preceding the index referral for primary PCI. * Hemodynamic instability or cardiogenic shock. Normal Control: Inclusion Criteria: * No clinically significant chronic or acute illness as determined by history, echocardiogram and/or available reports. Exclusion Criteria: * Subjects with pre-existing confounding factors, such as hypertension, diabetes mellitus, hyperlipidemia, CAD, known structural heart disease, left ventricular dysfunction, previous cerebrovascular event, malignancy, connective tissue or inflammatory disease, chronic infection, and hepatic or renal impairment will be excluded. * Possess abnormal cardiac structure and function after examination with ECHO All populations: Inclusion Criteria: * The subject is greater than or equal to 18 years of age at study entry. * Before any study procedure is carried out, the subject is able and willing to comply with study procedures and has provided signed and dated informed consent, including permission to access medical records. * The subject is male, or a female who is either surgically sterile (has had a documented bilateral oophorectomy and/or documented hysterectomy), postmenopausal (cessation of menses for more than 1 year), non-lactating, or of childbearing potential for whom the result of a urine pregnancy test performed before administration of IMP is negative. Exclusion Criteria: * Hypersensitivity to any component of 99mTc-NC100692 injection (e.g. p- aminobenzoate). * Pregnancy. * Unwillingness to provide and sign for informed consent. * Creatinine clearance \<30 ml/min.