Context: In Prader-Willi Syndrome (PWS), an altered GH secretion has been related to reduced cardiac mass and systolic function when compared to controls.

Objectives: To evaluate the cardiovascular response to GH therapy in adult PWS patients.

Study participants: 13 obese PWS adults (M/F 7/6, 26.9±1.2 yr, BMI 46.3±1.6 kg/m²).

Methods: Determination of IGF-I, metabolic parameters, echocardiography and cardioscintigraphy with dobutamine stimulation during 12-month GH therapy, with results analyzed by repeated-measures ANOVA.

Results: GH therapy increased IGF-I (p<0.0001), decreased C-reactive protein levels (p<0.05), and improved lean mass (p<0.001), fat mass (p<0.05) and visceral fat (p<0.001). Echocardiography showed that 6- and 12 month GH therapy increased left ventricle mass (LVM) in 76% and in 61% of patients, respectively (p<0.05), did not change diastolic function and slightly decreased the LV ejection fraction (LVEF) (p=0.054). Cardioscintigraphy documented stable values of LVEF throughout the study, while right ventricle EF decreased significantly (p<0.05) being normally responsive to dobutamine infusion. A positive association between IGF-I z-scores and LVEF occurred at the 6- and 12-month follow-up (p<0.05).

Conclusions: In PWS, GH therapy increased cardiac mass devoid of diastolic consequences. The observation of a slight deterioration of right-heart function, as well as the association between IGF-I and LV function during GH therapy, suggest the need for appropriate cardiac and hormonal monitoring in the therapeutic strategy for Prader-Willi Syndrome.