Raynaud's phenomenon and cardiac abnormalities are frequent in patients with systemic sclerosis. Radionuclide ventriculograms were obtained in 16 patients with Raynaud's phenomenon and systemic sclerosis or the related CREST syndrome and in 11 normal volunteers in order to evaluate changes in left ventricular function that might be induced by exposure to cold. Left ventricular regional wall motion abnormalities developed in nine of 16 patients during cooling compared with only one of 11 control subjects, despite a comparable rise in mean arterial pressure (p less than 0.02). The abnormalities occurred in seven of 11 patients with systemic sclerosis, one of four with CREST syndrome, and one with Raynaud's disease. To test the potential protective effect of nifedipine, radionuclide ventriculograms were then obtained during cooling after sublingual nifedipine (20 mg). Only five of 13 patients had wall motion abnormalities, and the severity of the abnormalities was significantly less than during the first cooling period (p = 0.03). Five of eight patients who had cold-induced wall motion abnormalities during the first cooling period had none after nifedipine, whereas two other patients demonstrated small abnormalities only during the second cooling period after treatment with nifedipine. It is concluded that cold induces segmental myocardial dysfunction in patients with systemic sclerosis and that nifedipine may blunt the severity of this abnormal response.