PolymyositisDermatomyositisMyositisHistidine-tRNA LigaseLung Diseases, InterstitialMyocytes, CardiacMyositis, Inclusion BodyCardiac OutputPrednisoloneMuscular DiseasesHeartCreatine KinaseAutoantibodiesMusclesParaneoplastic SyndromesArrhythmias, CardiacMuscle, SkeletalCardiac Surgical ProceduresConnective Tissue DiseasesDeath, Sudden, CardiacMyoglobinuriaScleroderma, SystemicNervous System Autoimmune Disease, ExperimentalAutoimmune DiseasesMediastinal EmphysemaAntibodies, AntinuclearImmunosuppressive AgentsMuscular DystrophiesMuscle WeaknessFatal OutcomeBiopsyMixed Connective Tissue Disease