- Healthy subjects (i.e., subjects without any history of chest pain or myocardial infarction, coronary artery bypass grafting surgery, coronary angiography with angioplasty and/or stenting, cerebrovascular accident, or peripheral vascular disease) with normal electrocardiograms and echocardiography on admission, and patients with coronary artery disease(i.e, patients with history of myocardial infarction, coronary artery bypass grafting operation, coronary angiography with angioplasty or stenting, heart failure secondary to coronary artery disease, or cerebrovascular accident).