Clinical Characteristics, Treatment, and Outcomes in Patients with Idiopathic Inflammatory Myopathy Concomitant with Heart Failure

This study sought to evaluate clinical features, treatment patterns, and outcomes of patients with idiopathic inflammatory myopathy (IIM) complicated by heart failure (HF). Thirty-two patients with IIM-HF admitted to the Peking Union Medical College Hospital between January 1999 and January 2018 were retrospectively reviewed, including 14 patients with polymyositis, 11 with dermatomyositis, and 7 with overlap syndrome. Survivors and no-survivors were compared on clinical characteristics and treatment. Although systemic symptoms were variable, all patients presented with elevated troponin I. Rapid atrial arrhythmia was the most frequent arrhythmia. Systolic dysfunction and restrictive diastolic dysfunction were typical presentations in echocardiography. Twenty-nine patients were followed up for a median of 2.8 years (0.1 month to 11 years). We recorded 13 deaths of cardiogenic cause, 1 of serious IIM, and 3 of infective complications. The median survival time from diagnosis of IIM-HF to all-cause mortality was 8.4 months (range from 1 month to 5 years). Both all-cause deaths and cardiogenic deaths were more reported in the methotrexate-alone group than in the combination therapy group (6/7 versus 3/10, P = 0.050; 5/6 versus 2/9, P = 0.041). Combination therapy including methotrexate (HR = 0.188, 95%CI 0.040-0.871, P = 0.033) and taking β-receptor blockers (HR = 0.249, 95%CI 0.086-0.719, P = 0.010) was associated with reduced risk of all-cause deaths. In conclusion, elevated troponin I, atrial arrhythmia, and systolic and restrictive diastolic dysfunction are typical characteristics of IIM-HF. Combined immunosuppression that includes methotrexate and β-receptor blockers seems to be important to improve survival.