The purpose of this study is to evaluate the cardiovascular function in patients with incomplete type of SSc (SSSD; Scleroderma Sjögren syndrome associated Spectrum Disorders), SSc (Systemic Scleroderma) and SLE (Systemic Lupus Erythematosus) by using ECG and digital plethysmograph. We also preformed ambulatory ECG monitoring for cases of SSSD and SSc with QT interval prolongation. 1) In ECG findings, ischemic myocardial damage, left ventricular hypertrophy or QT interval prolongation was observed in 33% cases of SSSD and 32% cases of SSc, respectively. In addition, parasympathetic disorders were observed in approximately 20% cases of SSSD, SSc and SLE. 2) Digital plethysmogram findings suggested that the peripheral vascular damage was present in both cases of SSSD and SSc, and its severity was lower in SSSD than SSc. The incidence of abnormal cardiovascular function tests in SSSD was relatively less than that in SSc. The cardiovascular function tests are useful to find cardiovascular abnormalities in these collagen diseases.