Study enrollment and interventions are temporarily paused due to lack of operational funding. This is not an IRB suspension.

The objective of this prospective, cross-sectional, multicenter pivotal trial study is to validate Infrasensor's clinical performance for the detection of high grade obstructive NSTE-ACS. High-grade obstructive NSTE-ACS is defined as an acute coronary syndrome in which severe obstructive coronary artery disease, including total coronary artery occlusion is present.

Study Endpoints Primary Endpoint: Infrasensor performance (Lower bound of 95% CI for sensitivity, specificity) between device detection of high-grade obstructive NSTE-ACS and angiographic diagnosis of High-grade obstructive CAD defined as the aggregate of >50% left main stenosis, or >70% stenosis in 1 or more coronary arteries and/or emergent revascularization.

Secondary Endpoint: Infrasensor performance (positive and negative predictive values, and overall accuracy).

Inclusion Criteria:

• Subject is willing and able to sign an Informed Consent
• Age: ≥18 years
• Study subjects with symptoms suggestive of ACS within 24 hours of presentation in an emergency department or acute care setting in whom invasive coronary angiography is intended.
• The following conditions for Infrasensor use must be present: The Infrasensor should only be used on alert patients who are able to keep the device still for the 5 minute measurement duration, who have clean, intact skin at the measurement site, and who do not have blood pressure cuffs, IV lines, or other medical equipment on the arm used for measurement.

Exclusion criteria:

• Patients with scars, open wounds, or lesions that may interfere with the Infrasensor application
• ACS patients triaged directly with STEMI or for cardiac reasons other than suspected AMI requiring immediate medical intervention (aortic dissection, unstable cardiac arrhythmias)
• Patients in whom an obvious alternative diagnosis is suspected at the time of arrival to hospital and without suspicion of ACS (pulmonary hypertension, musculoskeletal chest pain)
• Patients with acute myocardial infarction, percutaneous coronary intervention (including coronary stent placement), and/or coronary artery bypass graft surgery within the past 30 days
• Patients being hospitalized for acute coronary syndrome including NSTEMI who have hemodynamic instability (e.g., cardiogenic shock, unstable arrhythmias)
• Patients with planned coronary revascularization procedures (PCI or CABG) during the study period including patients who were evaluated previously for NSTEMI and determined to undergo a planned cardiac catheterization on an outpatient basis at a future time point.
• Hemodynamically unstable patients as defined by institutions protocol
• Trauma patients
• Patients with acute hemorrhage patients

The study population will be consecutive enrollment up to 350 patients presenting to the Emergency Department undergoing evaluation for an acute coronary syndrome in whom invasive coronary angiogram is also intended.

Individual participant data (IPD) will not be shared. The study includes detailed clinical, procedural, and imaging data collected to support regulatory evaluation of a proprietary investigational medical device. Due to confidentiality obligations, protection of participant privacy, and the absence of a pre-specified data-sharing plan, individual participant-level data will not be made publicly available.