Estimating the risk of future cardiovascular events such as death, stroke and myocardial infarction using traditional risk factors (such as age, gender, smoking, diabetes, hyperlipidaemia and hypertension) is well accepted in patients with and without existing cardiovascular disease. These estimates are based on a number of robust observational studies, including the original Framingham study. While these methods apply reasonably well on a population level their application to the individual patients is not always straightforward. In addition, risk charts, such as those published by the Joint British Societies and American Heart Association, may underestimate risk in certain groups, notably diabetics and patients of Indo-Asian background, whilst overestimating risk in others (by as much as 50% in some studies).

A number of variables including clinical, biochemical, and enzymatic have been evaluated to see if they add to conventional "risk-reduction" models such as Framingham and if so, to understand if they may be used in routine clinical practice.

The aim of this study is to assess several known and a few novel risk-factors (heart rate variability, pulse wave analysis, high-sensitivity CRP and BNP) prior to planned elective coronary angiography (cross-sectional analysis) and in a prospective cohort of high and low-risk patients.

Inclusion Criteria:

• Adults (18 years or older)
• Male or Female

Exclusion Criteria:

• Acute coronary syndrome
• Urgent angiography
• Assessment would constitute harm to patient
• Informed consent not obtained

ARM-CAD 1: Patients attending elective coronary angiography ARM-CAD 2: Participants in ARM-CAD 1 plus volunteers with cardiac risk factors