• exercise testing
• congestive heart failure
• peak oxygen uptake
• natriuretic peptides

Despite advances in treatment which have resulted in reductions in morbidity and mortality, heart failure remains a common condition often associated with a poor outcome. In most patients with chronic congestive heart failure, symptoms are not present at rest but become limiting with exertion. Despite this, the majority of measures used to characterise the severity of heart failure and prognosis are obtained at rest.

The New York Heart Association (NYHA) classification attempts to stratify patients according to their exercise limitation, but has a limited relation to objective measures of exercise tolerance and is a very subjective measure of disability. Self administered questionnaires which attempt to assess activity and exercise limitation are unable to measure functional capacity accurately and have only modest correlation with objective parameters such as peak oxygen uptake (pV̇o₂).

Making the diagnosis of heart failure can be difficult. Signs and symptoms lack both sensitivity and specificity. Although objective resting measures, such as left ventricular ejection fraction, can define structural cardiac abnormality, they are by no means synonymous with the diagnosis of heart failure. A further issue is the increased recognition of heart failure in subjects with normal left ventricular ejection fraction, and the difficulty of diagnosis in this patient group.

Exercise testing of patients, in combination with assessment of gas exchange parameters, is an attractive and practical method of obtaining accurate information which can aid in the diagnosis of heart failure as well as the assessment of functional limitation and prognosis.

Directly measured maximum oxygen uptake (more correctly pV̇o₂ in heart failure patients) has been shown to be a reproducible marker of exercise tolerance in heart failure and provide objective and additional information regarding patients clinical status and prognosis. Facilities for exercise testing with continuous measurement of gas exchange parameters are increasingly available. …