Patients who can perform greater than 5 metabolic equivalents (METS) on the Duke Activity Status Index (DASI) questionaire will be randomised between undergoing an Exercise ECG (Ex-ECG) or Exercise Stress Echo (ESE). The DASI is a 12-item questionnaire that estimates self-reported physical work capacity and is converted to an estimate of peak metabolic equivalents. Patients who do not meet this criteria, will undergo a pharmacological stress echocardiogram using Dobutamine (DSE), including Myocardial Contrast Echocardiography (MCE). Investigations will continue to be performed as per standard clinical departmental protocols as described below. In addition, all patients will undergo carotid ultrasonography. The techniques used are described for completeness as they are all well-established in clinical practice.