Abstract 18343: Antisynthetase Syndrome-Associated Myocarditis

Abstract

Background: The antisynthetase (AS) syndrome is characterized by fever, non-erosive arthritis, inflammatory myopathy, interstitial lung disease, cutaneous involvement, and antibody specificity. Cardiac involvement is extremely rare; we present one of two cases of AS syndrome-associated myocarditis from our institution. Clinical Case: A 51 year old woman with history of inflammatory arthritis and hypothyroidism presented with 6 months of increasing fatigue, bilateral proximal muscle weakness, leg edema, dyspnea, and orthopnea. Physical examination revealed a Caucasian woman, markedly dyspneic while speaking, with signs of acute decompensated heart failure (HF) including elevated jugular venous pulse, bilateral rales, S3 gallop, and massive peripheral edema with bilateral proximal upper and lower extremity weakness. Diagnostic Testing: Her muscle weakness was concerning for myopathy along with new HF symptoms. Laboratory studies revealed elevations of serum creatine kinase, aldolase, and cardiac troponin I. Thyroid stimulating hormone and free T4 were consistent with subclinical hypothyroidism. MRI and electromyography of the lower extremities and skeletal muscle biopsy were consistent with myositis. Anti-Jo1 antibody was positive, confirming the diagnosis of AS syndrome. Electrocardiogram showed sinus rhythm and low-voltages in all leads. Echocardiography showed severely depressed biventricular function, left ventricular (LV) ejection fraction of 10-15%, normal LV cavity size and wall thickness. Cardiac MRI and endomyocardial biopsy revealed active myocarditis. She received pulse dose corticosteroid therapy, intravenous furosemide, inotropic therapy, and hemofiltration therapy for renal failure. She was discharged home on intravenous dobutamine palliative therapy. Two months later, she presented in cardiogenic shock, failed intensive medical therapy, and died after a cardiac arrest. Conclusions: AS syndrome is a rare entity not typically associated with cardiac involvement. We report one of only two known cases of AS syndrome-associated myocarditis, to our knowledge. Based on these observations, we suggest that myocarditis be considered and evaluated for in patients with AS syndrome presenting with HF.