JDM patients had reduced HRV, which was associated with elevated inflammatory markers, active disease and reduced myocardial function. This suggests reduced vagal control of the heart; further studies are needed to determine whether this is also associated with cardiac morbidity or mortality.

After medium- to long-term followup, juvenile DM patients had decreased NCD and, often, neovascular pattern; both were associated with higher levels of disease activity and impaired muscle function. This suggests that NFC can be a biomarker for disease activity in longstanding juvenile DM too.