Heart failure has been defined in many ways and definitions change over time.
The multiplicity of definitions reflect the paucity of our understanding of the primary
underlying physiology of heart failure and the many diseases for which heart failure
is the common end-point. Fundamentally, heart failure represents a failure of the
heart to meet the body’s requirement for blood supply for whatever reason.
It is thus a clinical syndrome with characteristic features – not a single
disease in its own right. The syndrome includes symptoms and signs of organ underperfusion,
fluid retention and neuroendocrine activation. The syndrome arises from a range of
possible causes of which ischaemic heart disease is the commonest. From the point
of view of a clinician, the underlying pathology will determine treatment options
and prognosis. The extensive range of possible aetiologies present a diagnostic challenge
both to correctly identify the syndrome amongst all other causes of dyspnoea and
to identify the aetiology, allowing optimization of treatment.