A Study of SCAD Using Stress Contrast Echocardiography

Inclusion Criteria: * Adult \>18 years old * Patient has a history of spontaneous coronary artery dissection (SCAD) OR patient is healthy with no significant medical history Exclusion Criteria: * Unable to give consent * Allergic or have a history of adverse reaction to dobutamine, the Definity® ultrasound enhancing agent, or atropine. * Has a known or suspected hypersensitivity to perflutren and therefore cannot be given Definity®. * Pregnant. * Unable to interrupt breastfeeding. * Within 3 months of a heart attack. * Severe aortic stenosis. * Severe, uncontrolled hypertension (\>200/110 mmHg at baseline).