Subtle Alterations of Cardiac Performance in Children with Growth Hormone Deficiency: Results of a Two-Year Prospective, Case-Control Study

BACKGROUND: GH-deficient (GHD) children have reduced left ventricular (LV) mass, but impairment of cardiac function has never been documented. AIM: The aim of the study was to evaluate effects of GHD and GH therapy on cardiac function using load-dependent and load-independent indices of myocardial contractility. PATIENTS AND METHODS: Echocardiography was performed in 24 GHD children at baseline and 1 and 2 yr after GH therapy and in 24 controls. RESULTS: Compared with controls, GHD children at baseline had lower LV mass (LV mass/BSA 50.6 +/- 1.8 vs. 60.5 +/- 2.4 g/m(2); P < 0.002, and LV mass/H(2.7) 28.7 +/- 1.2 vs. 33.6 +/- 1.3 g/m(2.7); P < 0.009). Global systolic function was normal, with only a trend toward slight impairment of the fractional shortening (34.9 +/- 1.5 vs. 37.6 +/- 1.1%). However, subtle LV dysfunction was revealed by load-dependent and load-independent indices of myocardial contractility. In fact, GHD patients compared with controls showed lower rate-corrected mean velocity of circumferential fiber shortening (1.0 +/- 0.03 vs. 1.18 +/- 0.03 circ/sec; P = 0.0001) and stress shortening index (0.10 +/- 0.02 vs. 0.18 +/- 0.02; P < 0.007) and higher end-systolic stress (49.2 +/- 1.4 vs. 45.7 +/- 1.0 g/cm(2); P < 0.05). One year of GH treatment was associated with a significant improvement of cardiac size (LV mass/BSA 67.8 +/- 2.9 g/m(2); LV mass/H(2.7) 38.2 +/- 2.0 g/m(2.7); P < 0.0001 and P = 0.0003, respectively) and myocardial contractility (mean velocity of circumferential fiber shortening 1.2 +/- 0.04 circ/sec; P < 0.0002; stress shortening index 0.19 +/- 0.02; P < 0.003) and reduced afterload (end-systolic stress 43.9 +/- 1.4 g/cm(2); P < 0.03). CONCLUSIONS: Our data indicate that GH deficiency is associated with abnormalities in morphology and function in not only adults but also children and further supports the beneficial effect of GH on the heart.