In juvenile dermatomyositis, cardiac systolic dysfunction is present after long-term follow-up and is predicted by sustained early skin activity.

Abstract

To compare systolic cardiac function in patients with juvenile dermatomyositis (JDM) with matched controls and examine associations between systolic and diastolic cardiac function and disease variables. Fifty-nine patients, examined at follow-up, median 16.8 years (2-38 years) after disease onset, were compared with 59 age-matched and sex-matched controls. Echocardiography was performed and analysed blinded to patient information. We used mitral annulus displacement to assess the relative long-axis shortening of the left ventricle (long-axis strain) and early diastolic tissue velocity (e'), as markers for systolic and diastolic function, respectively. Disease activity and organ damage were assessed at follow-up by clinical examination and retrospectively by chart review. Long-axis strain was reduced in patients compared with controls (16.6% (2.5) vs 17.7% (2.0), mean (SD), p=0.001), whereas no difference was seen between patients with active and inactive disease. Disease duration correlated with systolic and diastolic function (rsp=-0.50 and rsp=-0.73, both p<0.001) and so did Myositis Damage Index (MDI) 1 year (rsp=-0.36 and rsp=-0.46) and MDI at follow-up (rsp=-0.33 and rsp=-0.60), all p<0.01. High early disease activity score (DAS) in skin (DAS skin 1 year), but not in muscle, predicted systolic (standardised β=-0.28, p=0.011, R(2)=48%) and diastolic dysfunction (β=-0.36, p<0.001, R(2)=72%) at follow-up. Long-axis strain was reduced in JDM patients compared with controls, suggesting systolic dysfunction. Impaired systolic and diastolic function was predicted by DAS skin 1 year. This indicates a common pathway to two different cardiac manifestations in JDM, perhaps with similar pathogenesis as skin affection.