Patients with coronary artery disease (CAD) and atrial fibrillation (AF) are at increased risk of stroke and heart attack. Such events are usually caused by increased stickiness of the blood causing a blood clot to block the artery (thrombus) in the heart or the brain. The aim of this study is to assess the stickiness of the blood (global thrombotic status) in patients with CAD and AF at baseline and after clinical stabilisation to see how disease state and clinical treatments affect the stickiness of the blood (thrombotic status). This will be a single centre study. Patients diagnosed with CAD or AF will have a blood sample taken at baseline and after clinical stabilisation. Blood stickiness will be tested with the Global Thrombosis Test. The results will be evaluated to assess the effect of disease process and clinical state on blood stickiness to gain further understanding of this condition and form the basis for future studies aimed at identifying patients who are at high risk of future cardiovascular events, based on increased blood stickiness.

Impaired thrombotic status is associated with adverse cardiovascular events. Patients with coronary artery disease (CAD) and atrial fibrillation (AF) are at increased risk of thrombotic events. It is not known whether thrombotic status differs in these patients, or how thrombotic status alters in response to clinical stabilisation with treatment.

The aim of this study is to assess the global thrombotic status (stickiness of the blood) in patients with coronary artery disease and atrial fibrillation at baseline and after clinical stabilisation.

This is a small, pilot, hypothesis-generating study. Design Single centre, hypothesis-generating study. Patients diagnosed with coronary disease (n=70) or atrial fibrillation (n=70) recruited from amongst in-patients or out-patients, will have a blood draw at presentation and after clinical stabilisation. Blood will be tested to assess global thrombotic status.

The recruitment period is 3 years.

Inclusion Criteria:

1. Male and female participants aged 18 years or over.
2. Patients diagnosed with CAD or AF and free of exclusion criteria below.
3. Not actively using tobacco products (due to vasoactive and pro-aggregatory effects of nicotine).
4. The participant is willing and able to understand the Subject Information Sheet and provide informed consent.
5. The participant must agree to comply with the drawing of blood samples for the assessments.

Exclusion Criteria:

1. Male and female participants aged < 18 years of age.
2. Patients with impaired renal function eGFR <30 ml/min (since renal failure is associated with platelet function defect that may confound results).
3. The participant has, in the opinion of the investigator, significant neurological, hepatic, renal, endocrine, cardiovascular, gastrointestinal, pulmonary, haemorrhagic metabolic or other disease likely to confound the study requirements or analyses.
4. The participant has a gives a history of substance abuse or demonstrates signs or clinical features of active substance abuse or psychiatric disease.
5. Alcohol consumption above recommended safe levels (i.e. more than 21 units per week for males, or more than 14 units per week for females) due to the potential effects of high alcohol levels on platelet reactivity.
6. Any illness deemed significant by the investigator during the four (4) weeks preceding the screening period of the study.
7. Any major bleeding diathesis or blood dyscrasia (platelets < 70 x 109/l, Hb <8 g/dl, INR>1.4, APTT> x 2UNL, leucocyte count< 3.5x 109/l, neutrophil count < 1x 109/l)
8. Currently enrolled in an investigational device or drug trial.

Patients diagnosed with coronary disease or atrial fibrillation. Participants will be recruited from amongst in-patients or out-patients