Hypokalemia, Diabetes Mellitus, and Hypercortisolemia are the Major Contributing Factors to Cardiac Dysfunction in Adrenal Cushing's Syndrome

Although cardiovascular complications are the major determinant of the prognosis of Cushing's syndrome (CS), factors contributing to the cardiovascular lesions are still unclear. We investigated clinical factors determining cardiac function in patients with adrenal CS. Fifty patients with adrenal CS were studied. Patients were divided into 3 groups based on their NYHA classification and electrocardiographic (ECG) findings: group A with NYHA grade 0 and normal ECG, group B with NYHA grade I and abnormal ECG, and group C with NYHA grade II or higher. Clinical and echocardiographic findings were compared between the groups. Heart failure of grade I or higher was seen in 40% and grade II or higher was seen in 8% of the patients. Age, HbA1c, and prevalence of diabetes mellitus were positively correlated and serum potassium levels were negatively correlated with the severity of cardiac dysfunction. Decreased ejection fraction (EF) and the ratio of the peak to late transmittal filling velocities (E/A), and increased left ventricular mass index (LVMI) were frequently observed. Multivariate analysis demonstrated that serum potassium and HbA1c levels were independent factors contributing to EF, while serum potassium and cortisol levels were independent factors contributing to LVMI. These results clearly demonstrated that hypokalemia, diabetes mellitus, and hypercortisolemia are the major contributing factors to cardiac dysfunction in adrenal CS. Strict control of these conditions is warranted for the prevention of cardiac dysfunction in adrenal CS.