Da Costa's syndrome is a syndrome with a set of symptoms that are similar to those of heart disease. While a physical examination does not reveal any gross physiological abnormalities, orthostatic intolerance has been noted. It was originally thought to be a heart 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.
The condition was named after Jacob Mendes Da Costa, who investigated and described the disorder during the American Civil War. It is also variously known as cardiac neurosis, chronic asthenia, effort syndrome, functional cardiovascular disease, neurocirculatory asthenia, primary neurasthenia, subacute asthenia and irritable heart.