Cardiac involvement in systemic diseases and secondary cardiomyopathies

Cardiovascular magnetic resonance (CMR) is an important tool for the evaluation of patients with systemic diseases and secondary cardiomyopathies such as sarcoidosis, systemic lupus erythematosus, the vasculitides, rheumatoid arthritis, the muscular dystrophies, and several others. Although the clinical manifestation of these systemic disorders can be variable, it is increasingly evident that a significant amount of cardiovascular involvement can exist prior to the development of obvious functional abnormalities such as a decrease in left ventricular ejection fraction. Because CMR can evaluate many aspects of heart disease such as cardiac structure and function, including, but not limited to, myocardial perfusion, fibrosis, and inflammation, these previously difficult-to-identify cardiac abnormalities associated with systemic diseases and secondary cardiomyopathies can readily be identified, even in the absence of abnormalities on other non-invasive tests. The basic time-efficient protocol includes assessment of function and focal fibrosis applying late gadolinium enhancement. Reversible changes can be detected by oedema imaging. Recent developments allow quantification of subtle changes using parametric mapping. Improved detection of heart disease in these patients allows for earlier initiation of medical therapy and may identify those at highest risk for developing complications such as heart failure, significant arrhythmias, and other potentially life-threatening problems. This chapter reviews the role of CMR in the evaluation and management of these disorders.