EMG fibrillation potentials (insertional activity) & positive sharp waves (Fib/PSW) are found in 95% study of 75 pts dx w/ idiopathic inflammatory myositis (44 PM, 17 DM, 7 ADM, 11 IBM); but also in 4 pts not meeting EULAR criteria https://t.co/VsrNjDMGnC https://t.co/OQYnUPJD5o