['To determine the significance of thallium perfusion defects in patients with systemic sclerosis (SSc).', "This is a followup study of a series of 48 SSc patients who underwent thallium perfusion scans in the early 1980s. Their cardiac history and survival information over the last 10 years were obtained as part of the Pittsburgh Databank's yearly evaluation. We determined the frequency of subsequent development of arrhythmias requiring treatment or of congestive heart failure through patient and physician information.", 'Patients with larger thallium perfusion defects had a significantly increased risk of developing subsequent cardiac events or death. The size of the initial thallium defect was the best predictor of later adverse events compared with other disease-related features, in a logistic regression analysis.'] Do thallium perfusion defects predict subsequent cardiac dysfunction in patients with systemic sclerosis?