Left ventricular systolic dysfunction (LVSD) is a cardiac involvement that is the leading cause of death among patients with systemic sclerosis (SSc). We aimed to define the clinical course and predictors of LVSD among SSc patients. We conducted a cohort study among adult patients with SSc who were followed up from 2013 to 2020. Semiparametric Cox regression analysis with robust clustering by cohort identification number was used to evaluate the predictors of LVSD. Among the 3, 987 person-years, LVSD was defined in 35 of 419 SSc patients for an incidence of 0.88 per 100 person-years. The median duration of the disease was 8.5 (interquartile range (IQR) 4.9-12.9) years. Every 1-point increase in the modified Rodnan skin score (mRSS) and salt and pepper skin were strong predictors of LVSD, with a respective adjusted hazard ratio (HR) of 1.05 and 3.17. During follow-up, 26 cases (74.3%) had unimproved LVSD. The strong predictors of the unimprovement of LVSD were every 1-point increase in mRSS (HR 1.05), every 1 mg increase in prednisolone treatment (HR 1.05), and every 1 U/L increase in creatine kinase (CK) (HR 1.001). Mycophenolate treatment was a protective factor against the unimprovement of LVSD in SSc (HR 0.15). LVSD was frequently found in patients with diffuse cutaneous SSc, and in most cases, it remained unimproved during follow-up. High mRSS, steroid use, and high CK levels were predictors of unimproved LVSD, whereas mycophenolate treatment might prevent the progression of LVSD. Steroids should be prescribed with caution in patients with longer disease duration.