Cardiac magnetic resonance imaging (MRI) has enabled the assessment of myocardial features, from tissue characteristics to functional changes, in patients with systemic lupus erythematosus (SLE). Echocardiography, however, detects cardiac decompensation. This study was undertaken to investigate the use of cardiac MRI to explore early warning signs of silent cardiac involvement and determine treatment timing in SLE.
Clinical assessment and cardiac MRI studies were performed in 50 drug-naive patients with new-onset SLE, 60 patients with longstanding SLE, and 50 healthy subjects in a 3-center prospective study.
Analysis of cardiac enzymes, the presence and size of regional myocardial fibrosis as indicated by late gadolinium enhancement, strain changes, and biventricular ejection fraction did not indicate cardiac impairment in the patients with new-onset SLE. Native myocardial T1 and extracellular volume (ECV), which are extracellular matrix indices, were elevated in the patients with new-onset SLE (mean ± SD 1,369 ± 79 msec versus 1,092 ± 57 msec in the control group for native T1; 32 ± 5% versus 24 ± 3% in the control group for ECV; P < 0.001 for both). The elevation was independent of SLE disease activity.
This is the first study to indicate that drug-naive patients with new-onset SLE, even those with inactive disease, are likely to have silent cardiac impairment. Structural and functional changes in the myocardium are related to SLE disease stage; this finding indicates the value of early detection of myocardial involvement. Native myocardial T1 values and ECV, rather than currently used clinical rheumatic and cardiac indices, could serve as early detection markers of myocardial injury before the presence of visual fibrosis and functional decompensation.