Echocardiographic dimensions and function in adults with primary growth hormone resistance (Laron Syndrome)

Patients with primary growth hormone (GH) resistance—Laron Syndrome (LS)—have no GH signal transmission, and thus, no generation of circulating insulin-like growth factor-I (IGF-I), and should serve as a unique model to explore the controversies concerning the long-term effect of GH/IGF-I deficiency on cardiac dimension and function. We assessed 8 patients with LS (4 men, 4 women) with a mean ( ± SD) age of 38 ± 7 years (range 22 to 45), and 8 aged-matched controls (4 men, 4 women) with a mean age of 38 ± 9 years (range 18 to 47) by echocardiography at rest, following exercise, and during dobutamine administration. Left ventricular (LV) septum, posterior wall, and end-diastolic diameter were significantly reduced in untreated patients with LS compared with the control group (p <0.05 for all). Systolic Doppler-derived parameters, including LV stroke volume, stroke index, cardiac output, and cardiac index, were significantly lower (p <0.05 for all) than in the control subjects, whereas LV diastolic Doppler parameters, including mitral valve waves E, A, E/A ratio, and E deceleration time, were similar in both groups. LV ejection fraction at rest as well as the stress-induced increment of the LV ejection fraction were similar in both groups. Our results show that untreated patients with long-term IGF-I deficiency have reduced cardiac dimensions and output but normal LV ejection fraction at rest and LV contractile reserve following stress.