Chronic refractory breathlessness is a distinct clinical syndrome.

Rigorous, systematic and empiric observations of the manifestations of diseases have formed the bedrockof clinicalpractice sinceSydenham reintroduced this into medical thinking in the 17 century. His conviction that meticulous description of the natural history of disease would eventually lead to an understanding of the appropriate treatment for that ailment was particularly apparent in his wide ranging observations about fever, gout, hysteria and attention to psychological health as a public health measure (‘The arrival of a good clown exercises a more beneficial influence upon the health of a town than of twenty asses laden with drugs.’ Thomas Sydenham), many of which still hold relevance today. Such an approach has served clinical medicine well. The delineation of a clinical syndrome, that is a constellation of clinical findings often accompanied by laboratory or imaging abnormalities, on many occasions has been the start of the road to develop effective interventions targeted at specific pathological process(es). This situation is illustrated by the clinical syndrome of heart failure because of left ventricular dysfunction, itself the final common pathway for a variety of pathological insults. Although the definition is still debated, a consensus working description has allowed systematic clinical recognition and assessment alongside research to understand the pathophysiological mechanisms involved and to develop and evaluate drug and device therapies. This process has resulted in targeted treatments, the widespread implementation of which has dramatically improved both quality and quantity of life for people with heart failure seen in successive national audits and the improved outcomes in the usual care placebo arms in controlled trials over time [1]. As many of the articles in this issue state, breathlessness is a common symptom of common chronic medical conditions. The same steps of clinical