If the heart fails to pump a sufficient amount of blood, it is crucial to know why in order to provide the best treatment. Pressure-volume analysis is the gold standard for evaluating the heart's pumping function. Unfortunately, current techniques are invasive, so most patients will not get this examination. By combining the strengths of echo-Doppler ultrasound, blood pressure monitoring and biomedical computing, the investigators aim to develop a non-invasive method for pressure-volume analysis, extending its applicability to more patients and settings.

Background: Current methods to evaluate left ventricular (LV) function either are invasive, precluding routine use in the majority of patients, or fail to discriminate myocardial, hemodynamic and structural factors, rendering assessment imprecise and incomplete.

Key question: Can we reliably obtain LV functional characteristics by non-invasive means, while being able to differentiate more precisely the factors involved? Proposed research: The study team aims to develop a non-invasive method for pressure-volume analysis (NIPVA) of the LV by combining echo-Doppler, peripheral blood pressure measurements and biomechanical modelling. The validity of this approach will be established by comparison with gold standard invasive measurements of pressure-volume relationships in patients undergoing cardiac catheterization. Test-retest reproducibility will be also assessed. The study team hypothesises that NIPVA will provide reproducible and valid measures of LV function and be more widely applicable.

Inclusion Criteria:

• Individuals, male or female, aged 18-80 years.
• 30 patients awaiting elective diagnostic coronary angiography will be recruited.
• 30 patients attending cardiology out-patient clinics will be recruited.

Exclusion Criteria:

• Patients with atrial fibrillation or other dysrhythmias or those unable to fully comply with the protocol will be excluded

Patients attending cardiology out-patient clinics