Purpose Anorexia nervosa (AN) is the most frequent eating disorder (ED), whose cardiac complications may have life-threatening consequences for both the physical and psychological health of affected children. In this study we reported and analysed the echocardiographic anomalies found in pediatric patients diagnosed with AN. Methods We reported the demographic and clinical characteristics of children aged 8 to 18 years, who were diagnosed with AN and underwent a complete cardiological evaluation at the Emergency Department of the Bambino Gesù Children's Hospital, IRCCS, Rome between the 1st January 2021 and the 30th June 2021. Furthermore, we compared the patients according to the presence of pericardial effusion and a BMI (Body Mass Index) cut-off 14.5 kg/m2. Results Forty-nine patients were included in the study. The mean age was 15.1 years. Most patients were female (89.8%). The mean length of hospitalisation was 18 days. The mean BMI at admission was 14.8 kg/m2, with a median weight loss of 9 kg in the last year. Eleven patients (22.4%) presented with cardiovascular signs or symptoms at admission. Most patients had pericardial effusion on heart ultrasound, with a mean thickness of 6 mm (SD ± 4). The LV (left ventricle) thickness over age was significantly higher in patients with pericardial effusion, with a Z score of -2.0 vs -1.4 (p = 0.014). The administration of psychiatric drugs was significantly more frequent in patients with a lower BMI (37.5% vs 12%, p = 0.038). Conclusion Our results suggest that it is reasonable, in patients presenting with AN, to perform complete cardiologic work-up to early identify and manage cardiac complications and their life-threatening consequences. Prospective and multi-center studies are required in order to characterise the cardiovascular abnormalities in patients with AN and to describe the evolution of these abnormalities after weight recovery.