Purpose: To investigate the cardiac effects of starvation in a group of adolescents with anorexia nervosa (AN). Methods: Twenty-five patients with AN (range 13-20 years), compared with 25 age-matched thin and 25 age-matched control women with body mass index > 20 Kg/m(2), underwent a complete clinical evaluation, including echocardiogram and 24-hour electrocardiogram monitoring to evaluate heart rate variability (HRV) indices. Results: Compared to both thin and control women, patients with AN had greater HRV time domain indices (SDNN: 246.5 +/- 32.4 vs. 170.4 +/- 24 ms and vs. 181 +/- 21.2 ms, p < .001), and in the frequency domain a lower LF/HF ratio (4.2 +/- 1.3 vs. 6.7 +/- 1.2 and vs. 6.8 +/- 1.3 ms, p < .001). AN patients showed reduced left ventricular mass with normal systolic function and typical diastolic patterns, characterized by a lower peak velocity transmitral flow in late diastole (peak A: 35.9 +/- 8.5 vs. 45.2 +/- 7.3 cm/sec and vs. 46.6 +/- 6.3 cm/sec, p < .01), a comparable peak velocity in early diastole (peak E: 92.7 +/- 12.1 vs. 83 +/- 6.2 and vs. 86.8 +/- 9.1 cm/sec, ns) and, subsequently, a greater E/A ratio (2.8 +/- 0.7 vs. 1.8 +/- 0.3 and vs. 1.9 +/- .5, p < .01) than thinness and control groups. Moreover, SDNN was also positively related to E/A ratio (r = .54, p < .01). Conclusions: Our findings demonstrate a cardiovascular vagal hyperactivity in AN, which appears to influence the ventricular diastolic dynamics. HRV and diastolic function analysis may represent useful tools in monitoring anorexia-induced cardiac modifications. (C) Society for Adolescent Medicine, 2003.