No Untoward Effect of Long-Term Ketoconazole Administration on Electrocardiographic QT Interval in Patients with Cushing's Disease.

Ketoconazole is listed among drugs that prolong QT interval and may increase the risk of torsade de pointes, a severe ventricular arrhythmia. This compound has recently been approved for treatment of Cushing's syndrome, a severe endocrine disorder. These patients harbour several risk factors for prolonged QT interval, for example hypokalaemia and left ventricular hypertrophy, but no study has evaluated whether administration of ketoconazole affects their QT interval. The aim of this study was to assess the QT interval in patients with Cushing's disease during long-term administration of ketoconazole. Electrocardiograms from 15 patients with Cushing's disease (12 women, 3 men, age: 37.8 ± 2.66 years) on ketoconazole treatment (100 mg-800 mg qd) for 1 month to 12 years were reviewed retrospectively. QT interval was measured and corrected for heart rate (QTc). Measurements before and during ketoconazole treatment were compared and any abnormal QTc value recorded. Concurrent medical therapies were also documented. On average, QTc was superimposable before and during ketoconazole treatment (393.2 ± 7.17 versus 403.3 ± 6.05 msec. in women; 424.3 ± 23.54 versus 398.0 ± 14.93 msec. in men, N.S.). QTc normalized on ketoconazole in one man with prolonged QTc prior to treatment; no abnormal QTc was observed in any other patient during the entire observation period, even during concurrent treatment with other QT-prolonging drugs. In conclusion, long-term ketoconazole administration does not appear to be associated with significant prolongation of QT interval in patients with Cushing's disease. ECG monitoring can follow recommendations drawn for other low-risk QT-prolonging drugs with attention to specific risk factors, for example hypokalaemia and drug interactions.

Clinical relevance of cardiac structure and function abnormalities in patients with Cushing's syndrome before and after cure.

OBJECTIVES: Sustained hypercortisolism impacts cardiac function, and, indeed, cardiac disease is one of the major determinants of mortality in patients with Cushing's syndrome. The aim of this study was to assess the clinical relevance of cardiac structure and function alterations by echocardiography in patients with active Cushing's syndrome and after disease remission. STUDY DESIGN: Seventy-one patients (61 women, 10 men) with Cushing's syndrome and 70 age-, sex- and blood pressure-matched controls were enrolled. Echocardiography was performed in 49 patients with active disease and at several time points after remission in 44 patients (median follow-up 46.4 months), and prevalence of abnormal left ventricular mass measurements and systolic and diastolic functions indices was compared between patients with active disease, after remission and controls. Twenty-two patients were evaluated both before and after remission. RESULTS: Up to 70% of patients with active Cushing's syndrome presented abnormal left ventricular mass parameters; 42% presented concentric hypertrophy and 23% concentric remodelling. Major indices of systolic and diastolic functions, i.e. ejection fraction and E/A ratio, respectively, were normal. Upon remission of hypercortisolism, left ventricular mass parameters ameliorated considerably, although abnormal values were still more frequent than in controls. Both cortisol excess and hypertension contribute to cardiac mass alterations and increase the prevalence of target organ damage. CONCLUSIONS: Cushing's syndrome is associated with an increased risk for abnormalities of cardiac mass, which ameliorates, but does not fully disappear after remission. Systolic and diastolic functions are largely within the normal range in these patients.

The pituitary-adrenal axis in adult thalassaemic patients.

OBJECTIVE: We previously described in young thalassaemic patients an altered cortisol and ACTH responsiveness suggesting an impaired adrenocortical reserve. Owing to iron overload, a worsening of adrenal function should be expected in adult patients. DESIGN: In 124 adults with beta-thalassaemia, urinary free cortisol (UFC) and plasma ACTH levels were determined and compared with those measured in 150 controls. In 45 patients, cortisol was measured in response to: i) tetracosactide 1 microg as an i.v. bolus (low-dose test, LDT) and ii) tetracosactide 250 microg infused i.v. over 8 h (high-dose test, HDT). RESULTS: UFC and serum cortisol were within the reference range in all patients. Conversely, basal plasma ACTH values were above the upper limit of the normal range in 19 patients. There were no statistically significant differences in the mean values of UFC, basal serum cortisol and plasma ACTH between patients and controls. A subnormal cortisol response to the LDT was registered in 18 out of 56 patients. Three of these patients also displayed a subnormal response to the HDT, together with elevated baseline plasma ACTH levels. In the LDT, a positive correlation was found between basal and peak cortisol values (P<0.0001). The latter were negatively correlated with basal ACTH values in both LDT (P<0.0001) and HDT (P<0.0001). CONCLUSIONS: Adult thalassaemic patients often present a subtle impairment of adrenocortical function. This may become clinically relevant in case of major stressful events. Thus, we recommend an assessment of adrenocortical function in all adult thalassaemic patients.