Increased myocardial fibrosis and left ventricular dysfunction in Cushing's syndrome.

OBJECTIVE: Active Cushing's syndrome (CS) is associated with cardiomyopathy, characterized by myocardial structural, and ultrastructural abnormalities. The extent of myocardial fibrosis in patients with CS has not been previously evaluated. Therefore, the objective of this study was to assess myocardial fibrosis in CS patients, its relationship with left ventricular (LV) hypertrophy and function, and its reversibility after surgical treatment. DESIGN AND METHODS: Fifteen consecutive CS patients (41±12 years) were studied together with 30 hypertensive (HT) patients (matched for LV hypertrophy) and 30 healthy subjects. Echocardiography was performed in all patients including i) LV systolic function assessment by conventional measures and by speckle tracking-derived global longitudinal strain, ii) LV diastolic function assessment using E/E', and iii) myocardial fibrosis assessment using calibrated integrated backscatter (IBS). Echocardiography was repeated after normalization of cortisol secretion (14±3 months).
RESULTS: CS patients showed the highest value of calibrated IBS (-15.1±2.5  dB) compared with HT patients (-20.0±2.6  dB, P<0.01) and controls (-23.8±2.4  dB, P<0.01), indicating increased myocardial fibrosis independent of LV hypertrophy. Moreover, calibrated IBS in CS patients was significantly related to both diastolic function (E/E', r=0.79, P<0.01) and systolic function (global longitudinal strain, r=0.60, P=0.02). After successful surgical treatment, calibrated IBS normalized (-21.0±3.8 vs -15.1±2.5  dB, P<0.01), suggestive of regression of myocardial fibrosis.
CONCLUSIONS: Patients with CS have increased myocardial fibrosis, which is related to LV systolic and diastolic dysfunction. Successful treatment of CS normalizes the extent of myocardial fibrosis. Therefore, myocardial fibrosis appears to be an important factor in the development and potential regression of CS cardiomyopathy.