Replacement and reactive myocardial fibrosis in idiopathic dilated cardiomyopathy: comparison of magnetic resonance imaging with right ventricular biopsy

Background The presence of focal myocardial fibrosis, also called scar or replacement fibrosis, detected with late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (CMR) is a predictor of adverse outcome in patients with idiopathic dilated cardiomyopathy (DCM).1,2 Increased interstitial (reactive) fibrosis determined with histological staining from endomyocardial biopsy (EMB) specimens has been described in DCM and associated with an adverse prognosis and impaired response to therapeutic interventions in selected groups of patients with DCM.3-6 Aims We sought to describe the patterns of focal fibrosis in a group of patients with DCM and correlate focal fibrosis with interstitial fibrosis, myocardial viral load, and inflammation. A pilot study in 10 autopsies was performed to compare interstitial fibrosis from right ventricular (RV) with left ventricular (LV) EMB. Methods Study subjects were 60 consecutive patients with DCM (globally impaired systolic LV function not due to myocardial infarction, signifi-cant coronary artery disease, hypertension, valvular disease, or other known causes) referred to our hospital for EMB and CMR. Patients (n 1) with infarct-like subendocardial or transmural LGE within the territory of a coronary artery and corresponding regional wall motion abnormalities only were not included to avoid the inclusion of patients with an embolic event. Three patients did not agree to participate resulting in a study population of 56. The study was approved by the Hospital Ethics Committee and all patients gave written informed consent.