Background: Systemic sclerosis (SSc) is a chronic connective tissue disorder of unknown etiology, characterized by cutaneous and visceral involvement.The pathogenesis of the cardiac lesion in SSc is controversial, but the primary disorder of microvasculature with diffuse arteriolar and capillary lesions could precede any fibrosis, thus causing ischemic disorder to the heart. Dobutamine stress echocardiography (DSE) is a sensitive predictor of coronary artery disease. This study was performed to assess the value of DSE for noninvasive diagnosis of cardiac involvement in patients with SSc without clinical evidence of heart disease and to determine if abnormal responses to dobutamine can be explained by a decreased coronary flow velocity reserve (CFVR).<br/> Methods: We studied 27 patients with SSc without clinical evidence of heart disease, (15 with diffuse form and 12 with localized form of SSc), age 54±12. All patients underwent high dose DSE testing (5-40 mcg/kg/min) and evaluation of CFVR in the left anterior descending coronary artery with contrast transthoracic Doppler during adenosine infusion (140 µg/Kg/min in 5 minutes). Patients were divided into two groups based on the absence (group A; n=15) or presence ( group B; n=13) of regional wall motion abnormalities (RWMA) on DSE.<br/> Results: In 13 out of 28 pts (46%) with SSc, we found RWMA during DSE with patchy distribution. Both groups showed normal CFVR values (group A, 2.76±0.7; group B, 2.26±0.4), but CFVR in group B was statistically reduced compared to group A (p=0.03).<br/> Conclusion: This study showed that many patients with SSc, without clinical evidence of heart disease, have inducibile RWMA during DSE with patchy distribution. Furthemore, CFVR reduction suggests the role of a partial coronary microvascular dysfunction in these group of patients.