Multimodality imaging and the emerging role of cardiac magnetic resonance in autoimmune myocarditis.
ABSTRACT Autoimmune responses and inflammation are involved in the excess cardiovascular risk observed in patients with systemic inflammatory diseases. Autoimmune myocarditis is a presentation of an inflammatory reaction of the heart during the course of autoimmune disorders, with most cases seen in systemic lupus erythematosus. Early diagnosis is of great significance because of the likelihood of progression to severe and potentially fatal complications such as arrhythmias, heart block, and heart failure. The clinical presentation of the disease is silent leading to delayed diagnosis when dilated cardiomyopathy or heart failure has already advanced. Therefore, a major issue is whether the diagnosis of myocarditis will continue to require invasive procedures such as endomyocardial biopsy or can be achieved with non-invasive methods. There is increasing evidence that noninvasive cardiac imaging, including tissue Doppler echocardiography and cardiac magnetic resonance (CMR), is able to detect subclinical cases and aid in the initiation of specific treatment when it is more likely to be effective. CMR in particular, has emerged as an important technique in the evaluation of myocarditis using three types of images: T2-weighted (T2-W), early T1-weighted (EGE) images taken after 1min, and delayed enhanced images (LGE) taken 15min after the injection of contrast agent. If 2/3 of the imaging sequences are positive, myocardial inflammation can be predicted or ruled out with a diagnostic accuracy of 78%. As our understanding of disease mechanisms improves, multimodality imaging may aid in the development of new diagnostic and therapeutic strategies for this potentially devastating complication of systemic inflammation, but further studies are needed to formally evaluate this.
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ABSTRACT: The last few decades have witnessed an increased life expectancy of patients suffering with systemic rheumatic diseases, mainly due to improved management, advanced therapies and preventative measures. However, autoimmune disorders are associated with significantly enhanced cardiovascular morbidity and mortality not fully explained by traditional cardiovascular disease (CVD) risk factors. It has been suggested that interactions between high-grade systemic inflammation and the vasculature lead to endothelial dysfunction and atherosclerosis, which may account for the excess risk for CVD events in this population. Diminished nitric oxide synthesis-due to down regulation of endothelial nitric oxide synthase-appears to play a prominent role in the imbalance between vasoactive factors, the consequent impairment of the endothelial hemostasis and the early development of atherosclerosis. Asymmetric dimethylarginine (ADMA) is one of the most potent endogenous inhibitors of the three isoforms of nitric oxide synthase and it is a newly discovered risk factor in the setting of diseases associated with endothelial dysfunction and adverse cardiovascular events. In the context of systemic inflammatory disorders there is increasing evidence that ADMA contributes to the vascular changes and to endothelial cell abnormalities, as several studies have revealed derangement of nitric oxide/ADMA pathway in different disease subsets. In this article we discuss the role of endothelial dysfunction in patients with rheumatic diseases, with a specific focus on the nitric oxide/ADMA system and we provide an overview on the literature pertaining to ADMA as a surrogate marker of subclinical vascular disease.International Journal of Molecular Sciences 01/2012; 13(10):12315-35. · 2.46 Impact Factor