Diagnosis
Although it is listed in the ICD-9 (306.2) and ICD-10 (F45.8) under "somatoform autonomic dysfunction", the term is no longer in common use by any medical agencies and has generally been superseded by more specific diagnoses. The orthostatic intolerance observed by Da Costa has since also been found in patients diagnosed with chronic fatigue syndrome, postural orthostatic tachycardia syndrome (POTS) and mitral valve prolapse syndrome. In the 21st century, this intolerance is classified as a neurological condition. Exercise intolerance has since been found in many organic diseases. Classification
There are many names for the syndrome, which has variously been called soldiers heart, cardiac neurosis, chronic asthenia, effort syndrome, functional cardiovascular disease, neurocirculatory asthenia, primary neurasthenia, and subacute asthenia. Da Costa himself called it irritable heart  and the term soldiers heart was in common use both before and after his paper. Most authors use these terms interchangeably, but some authors draw a distinction between the different manifestations of this condition, preferring to use different labels to highlight the predominance of psychiatric or non-psychiatric complaints. For example, Oglesby Paul writes that "Not all patients with neurocirculatory asthenia have a cardiac neurosis, and not all patients with cardiac neurosis have neurocirculatory asthenia." None of these terms have widespread use. Treatment
The report of Da Costa shows that patients recovered from the more severe symptoms when removed from the strenuous activity or sustained lifestyle that caused them.
Da Costas syndrome (also known as "soldiers heart", cardiac neurosis, chronic asthenia, effort syndrome, functional cardiovascular disease, neurocirculatory asthenia, primary neurasthenia, subacute asthenia and irritable heart) is a psychiatric syndrome which presents a set of symptoms similar to those of heart disease. These include fatigue upon exertion, shortness of breath, palpitations, sweating, and chest pain. While a physical examination does not reveal any gross physiological abnormalities, orthostatic intolerance has been noted. It was originally thought to be a cardiac condition, and treated with a predecessor to modern cardiac drugs. While the condition was eventually recategorized as psychiatric, in modern times, it is known to represent several disorders, some of which now have a known medical basis. For stress-related combat disorders generally, see post-traumatic stress disorder. Historically, similar forms of this disorder have been noticed in various wars, like the American Civil War and Crimean war, and among British troops who colonized India. The condition was named after Jacob Mendes Da Costa who investigated and described the disorder in 1871. Signs and symptoms
Symptoms of Da Costas syndrome include fatigue upon exertion, weakness induced by minor activity, shortness of breath, palpitations, sweating, and chest pain. Causes
Da Costas syndrome was originally considered to be heart failure or other cardiac condition, and was later recategorized to be psychiatric. The term is no longer in common use by any medical agencies and has generally been superseded by more specific diagnoses, some of which have a medical basis.