[Clinical analysis of vasovagal syncope in children]

To study the changes in clinical features of vasovagal syncope (VVS) in children.

From January 2000 to September 2009, 841 children with unexplained syncope or prodromata were enrolled. They were assigned to two groups according to the period of visiting hospital: group A (from January 2000 to December 2004, n=129) and group B (from January 2005 to September 2009, n=712). They were assigned to three age groups: 4-6 years old, 7-10 years old and 11-18 years old. A head-up tilt table test (HUTT) was performed on all the subjects.

The total positive rate of HUTT was 45.3% (381/841). Compared with that in group A, the positive rate of HUTT in group B increased significantly (47.5% vs 33.3%; P<0.05). The positive rate of HUTT in female children was significantly higher than that in male children (49.3% vs 37.9%; P<0.05). The positive rate of HUTT increased with age and it was the highest in children at age of 11-18 years (49.2%), followed by in children at age of 7-10 years (44.1%) and 4-6 years (37.1%) (P<0.05). The children at age of 7-10 years and 11-18 years from group B showed significantly higher positive rate of HUTT than those from group A (46.2% vs 27.8%; 54.0% vs 32.6%, P<0.05). Vasodepressor type was the most common response type (70.9%) shown by HUTT compared with mixed type (25.5%) and cardioinhibitory type (3.6%) (P<0.05). The proportion of children with vasodepressor response type in group B was significantly higher than that in group A (72.5% vs 58.1%; P<0.05).

There were obvious changes in the prevalence of VVS and response types before and after five years, suggesting that the development of VVS may be attributed to many factors, such as social factors, mental factor and life style.