 Coronary artery disease CAD, cholesterol plaque buildup in the heart arteries is the most common cause of left ventricular systolic dysfunction weakening of the heart muscle. The standard test to find coronary artery disease is coronary angiography. This test is highly accurate but is invasive and carries a small risk of complications. This study investigates ultrasound of the carotid neck arteries as a screening test for severe coronary artery disease as a cause of left ventricular systolic dysfunction. It is hypothesized that carotid ultrasound will have excellent negative predictive value for severe CAD. 