Cardiovascular events in patients with myositis: results from a French retrospective cohort.

Introduction: Idiopathic inflammatory myositis (IIM) are systemic diseases, including dermatomyositis (DM), inclusion body myositis (IBM), immune-mediated necrotising myopathy (IMNM), antisynthetase syndrome (ASSD) and overlap myositis (OM). Patients with IIM have an increased risk of premature death, largely due to cardiovascular events (CVE). The aim of this study was to describe specific and non-specific cardiac involvement in patients with IIM, and to assess the occurrence of CVE.

Methods: We conducted a retrospective observational cohort study of patients with IIM from Saint Antoine University Hospital, Paris, between 1997 and 2020. Cardiac involvement was defined as abnormalities at baseline on ECG, Holter ECG, transthoracic echocardiography, cardiac MRI or elevated cardiac biomarkers. CVE were defined as heart failure due to ischaemia, arrhythmia or conductive block, inflammatory myocarditis or resuscitation department admission.

Results: 78 patients were included (median age 49 years; 67% female); 33 (42%) had DM, 18 (23%) ASSD, 12 (15%) OM, 11 (14%) IMNM and 4 (5%) IBM. Cardiac involvement at diagnosis was present in 12 (15%) patients; 15 (19%) had a CVE during follow-up. Patients with versus without cardiac involvement at diagnosis were more likely to present a CVE (6 (50%) vs 9 (14%); p=0.01). Median (IQR) time to CVE was shorter in patients with cardiac involvement (9 (0-34) vs 84 (26-156) months; p<0.01).

Conclusion: Patients with cardiac involvement at myositis diagnosis are at increased risk of CVE and experience them earlier than patients without and should be carefully followed up, particularly during the first months after diagnosis.