To investigate the clinical characteristics of small heart syndrome (SHS) in children.

A total of 8 children with SHS who were treated in the Cardiovascular department of Sun Yat-sen Memorial Hospital of Sun Yat-sen University from March 2016 to December 2017 were selected as research objects and included in SHS group. By using the method of simple random sampling, 8 healthy children who underwent physical examination in the outpatient department of the same hospital in the same period were selected and included in control group. The clinical data or physical examination records of 16 children were analyzed retrospectively. The general clinical data, heart rate fluctuation range, blood pressure and sum of the distance between both hilus pulmonis and the middle line between two groups were statistically compared by independent-samples t test. This study was in line with World Medical Association Declaration of Helsinki revised in 2013, with the informed consent of the guardians of all testees.

①There were no significant differences between two groups in proportion of males, age, weight, height, body surface area, body mass index (BMI), systolic blood pressure and diastolic blood pressure (P>0.05). The range of heart rate fluctuation in SHS group was (117.9±20.1) beats/min, which was higher than that of (94.8±3.9) beats/min in control group; the sum of the distance between both hilus pulmonis and the middle line of SHS group was (88.3±10.5) mm, which was shorter than that of (99.3±5.7) mm in control group, and the differences were statistically significant (t=3.191, P=0.007; t=2.587, P=0.021). ②Among 8 SHS children in SHS group, 5 cases (62.5%, 5/8) were diagnosed as ematiation. Six cases (75.0%, 6/8) presented clinical symptoms, such as chest blockage, chest pain, palpitation, fatigue or dizziness. When chest blockage, chest pain and other possible symptoms attacked in 8 SHS children, their heart rate significantly increased, heart rate fluctuated in a wide range and blood pressure decreased. Four SHS children (50.0%, 4/8) were complicated with sinus arrhythmia. No specific abnormal changes were found of 8 SHS children in myocardial zymogram, 24 h dynamic electrocardiogram (Holter) and color Doppler echocardiography (CDE). ③After taken sufficient rest of children in SHS group, the clinical symptoms as mentioned above could be relieved. The SHS pregnant women were followed up for 18 to 36 months after discharged, and no SHS related clinical symptoms were found in them again.

The clinical manifestations of children with SHS were diversified. For the thin and small children with chest blockage and dizziness, chest X-ray examination should be carried out and the cardiothoracic ratio (CTR) should be measured in order to avoid missed diagnosis and misdiagnosis of SHS.