Polymyositis presenting with cardiac manifestations: Report of two cases and review of the literature

Is it cardiac involvement mimicking acute myocardial infarction in idiopathic inflammatory myopathy?

Idiopathic inflammatory myopathy (IIM) comprises a group of rare systemic diseases characterized by progressive weakness of the symmetrical proximal limb muscles, elevated muscle enzymes, inflammation or necrosis on muscle biopsy. IIM may impair the function of multiple organs, particularly the heart. However, it rarely manifests as acute myocardial infarction (AMI) at initial presentation. The present study described the case of a 39-year-old woman with AMI, whose muscle biopsy on the left arm conformed to polymyositis. Coronary arteriography showed irregularities in the left descending and right coronary artery (25% diameter reduction in middle segment). It was concluded that AMI was the chief manifestation of IIM at initial presentation. Furthermore, to the best of our knowledge, the present study was the first to provide a systematic literature review to assess AMI in IIM patients and discuss the possible causes of AMI.

Cardiac involvement in adult and juvenile idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM) include the main subgroups polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM) and juvenile DM (JDM). The mentioned subgroups are characterised by inflammation of skeletal muscles leading to muscle weakness and other organs can also be affected as well. Even though clinically significant heart involvement is uncommon, heart disease is one of the major causes of death in IIM. Recent studies show an increased prevalence of traditional cardiovascular risk factors in JDM and DM/PM, which need attention. The risk of developing atherosclerotic coronary artery disease is increased twofold to fourfold in DM/PM. New and improved diagnostic methods have in recent studies in PM/DM and JDM demonstrated a high prevalence of subclinical cardiac involvement, especially diastolic dysfunction. Interactions between proinflammatory cytokines and traditional risk factors might contribute to the pathogenesis of cardiac dysfunction. Heart involvement could also be related to myocarditis and/or myocardial fibrosis, leading to arrhythmias and congestive heart failure, demonstrated both in adult and juvenile IIM. Also, reduced heart rate variability (a known risk factor for cardiac morbidity and mortality) has been shown in long-standing JDM. Until more information is available, patients with IIM should follow the same recommendations for cardiovascular risk stratification and prevention as for the corresponding general population, but be aware that statins might worsen muscle symptoms mimicking myositis relapse. On the basis of recent studies, we recommend a low threshold for cardiac workup and follow-up in patients with IIM.

Decreased flow-mediated dilatation with increased arterial stiffness and thickness as early signs of atherosclerosis in polymyositis and dermatomyositis patients

Several autoimmune rheumatic diseases have been associated with accelerated atherosclerosis or other different types of vasculopathy depending on the underlying disease, leading to increased cardio- and cerebrovascular disease risk. Polymyositis (PM) and dermatomyositis (DM), members of idiopathic inflammatory myopathies (IIMs), a group of systemic autoimmune diseases are also associated with elevated risk of cardiovascular diseases (CVD). Up until now, no specific data is known on the mechanisms, risk factors, or possible vasculopathy leading to increased CVD risk. The aims of the present study were to assess the flow-mediated dilatation of the brachial artery by a TensioClinic arteriograph and to measure the thickness of carotid artery intima-media, the augmentation index, and the pulse wave velocity using high-resolution ultrasonography in a cohort of PM and DM patients. We also investigated the correlation of these parameters with the traditional risk factors of atherosclerosis and overall cardiovascular status within PM and DM patients. Twenty-seven patients (21 females, six males) with IIMs were enrolled in this study, and 38 healthy individuals matched for sex and age served as controls. We found a decreased flow-mediated dilatation in the brachial artery (6.36 vs. 8.39 %) with increased arterial stiffness and carotid artery thickness in our patients compared to healthy controls. We found significantly decreased flow-mediated dilatation of the brachial artery (5.57 vs. 8.39 %) in DM patients. We also detected a correlation between these parameters and the traditional cardiovascular risk factors, as well as hypertriglyceridemy, hypertension, and peripheral arterial disease. In DM, overall, more vascular abnormalities were found than in PM. Our findings suggest that flow-mediated dilatation of the brachial artery, arterial stiffness, and carotid artery thickness measurements could be beneficial for predicting the CVD risk in myositis patients. Further investigations need to find the potential differences and role of inflammation and immune mechanisms in atherosclerotic processes in DM and PM.