Based on analyses of studies separately of the SCORE study, sponsor has decided to discontinue the Study. Data collected during the study will not be analyzed

The purpose of this study is to validate the accuracy of the SPIROCOR System in indicating the presence of significant coronary artery disease (S-CAD), as defined in ACC/AHA Guidelines, in subjects with suspected S-CAD.

Inclusion Criteria:

• Subject with suspected S-CAD
• Subject able to perform the guided breathing protocol and comply with study requirements
• Subject is able and agrees to sign the informed consent form

Exclusion Criteria:

• Resting (supine) ECG evidence of ST-segment depression ≥ 1 mm in any lead or left bundle branch block or significant arrhythmia
• Current digoxin therapy
• Subject has severe valvular heart disease
• Subject has congestive heart failure NYHA class III/IV
• Subject has known history of myocardial infarction (ST elevation or non ST elevation)
• Subject had previous coronary revascularization: CABG or PCI
• Subject has pacemaker or ICD that controls sinus
• Morbidly obese subject (BMI ≥ 40)
• Subject has any significant medical condition which, at the investigator's discretion, may interfere with the subject's optimal participation in the study; and
• Subject is currently participating in another investigational product clinical study that the investigator believes may interfere with the outcome of this study

Subjects referred to cardology clinics for evaluation of severe coronary artery disease (S-CAD)