A 42-yr-old woman with dermatomyositis had two myocardial infarctions, episodes of acute chest pain and an acute lung oedema. These events were initially misinterpreted as atherosclerotic ischaemic heart disease accompanying the autoimmune disease. The lack of improvement of cardiac symptoms with anti-ischaemic and immunosuppressive drugs indicated other mechanisms. Intracoronary drug provocation as well as myocardial biopsy revealed a coincidence of small-vessel disease and vasospastic angina as a cause for the severe cardiac symptoms. After initiating therapy with high doses of calcium channel blockers, marked improvement of cardiac symptoms occurred. In the pathogenesis of cardiac involvement in dermatomyositis, two different mechanisms should be considered: inflammatory processes due to dermatomyositis and vasoconstriction caused by an impaired regulation of vascular tone, such as abnormal vessel reactivity or disturbed neuropeptide release. Signs of this generalized vasopathy are Raynaud's phenomenon, Prinzmetal's angina and small-vessel disease, which can coincide. In patients with severe cardiac symptoms and autoimmune diseases, Prinzmetal's angina should be excluded by intracoronary drug provocation using acetylcholine.