ARMCAD

Alternative Risk Markers in Coronary Artery Disease

This investigator-initiated study began recruiting study participants at CTC in 2007 and will evaluate the ability of heart rate variability (HRV) and pulse wave analysis (PWA) to predict extent of coronary disease.

Risk prediction using 'traditional' risk factors (such as age, gender, smoking, diabetes, hyperlipidaemia and hypertension) is well documented.  Indeed, there are clear and convincing correlates between these parameters and the risk of death due to coronary heart disease (CHD) as well as its clinical manifestations.  With an ageing population, it becomes increasingly important to identify those at particular risk of coronary events.  Targeting interventions and therapies to appropriate groups is also of major economic importance.  Unfortunately, such risk information is based on population samples, and is not consistently useful for individual patients.

Heart rate variability (HRV) is a measure of cardiac autonomic function; dysfunction of which can lead to arrhythmias and impaired myocardial blood flow.  Lower HRV is associated with sudden cardiac death, all-cause mortality and mortality post-infarct, as well as risk of developing CHD.

Pulse wave analysis (PWA) is a non-invasive method of determining endothelial function.  The peripheral artery pressure waveform, measured by a tonometer and calibrated by blood pressure, provides a measure of systemic arterial stiffness.  Recent studies have shown that aortic pulse wave velocity also predicts cardiovascular disease and provides prognostic data beyond that gained from traditional risk factors.

The Intelliheart unit incorporates non-invasive devices that record blood pressure, heart-rate variability and pulse-wave analysis.  This information is combined with age, gender, smoking, diabetes history and blood cholesterol/HDL measurements to determine a risk score for cardiovascular disease.  The individual components and overall results of each assessment are compiled into a computer database and then archived for later use in statistical programs.