[Ambulatory blood pressure in children with neurally mediated syncope]

To discuss the variation of parameters in ambulatory blood pressure for neurally mediated syncope (NMS) in children, and to analyze the diagnostic value of ambulatory blood pressure pattern in children with NMS.

Forty-seven children with NMS [20 males and 27 females, mean age (11.7+/-2.8) years] who came from Peking University First Hospital from July, 2007 to March, 2008 were included in the study. Twenty -three healthy children [12 males and 11 females, mean age (11.0+/-3.2) years] were recruited as control group. And the hemodynamic patterns of NMS were detected. Based on the hemodynamic patterns, they were divided into vasovagal syncope (VVS) group [16 children in total, 7 males and 9 females, mean age (11.5+/-2.8) years] and postural tachycardia syndrome (POTS) group [31 children in total, 13 males and 18 females, mean age (11.7+/-2.9) years]. Parameters of children with different hemodynamic patterns in ambulatory blood pressure and diagnostic value of ambulatory blood pressure pattern were analyzed. SPSS 10.0 software was used for the statistical analysis of these data.

Mean diastolic pressure of the whole day, mean diastolic pressure in the day-time and mean systolic pressure at night in POTS group were higher than those of the control group, reapectively (P<0.05), and they increased by 8.26%, 6.66% and 6.03%, respectively, but there were no significant differences between VVS group and control group (P>0.05). The systolic pressure differences in the day-time and at night in VVS group and POTS group were lower than those of the control group, respectively (P<0.01), and they decreased by 35.92% and 28.42%, respectively. There were no significant differences in the mean systolic pressure of the whole day, mean systolic pressure in the day-time, mean diastolic pressure at night and diastolic pressure difference in the day-time and at night among VVS group, POTS group and control group, respectively (P>0.05). The non-spoon pattern rate of fluctuation curve of ambulatory blood pressure in VVS group and POTS group was higher than that of the control group (68.8% vs 17.4%, 64.5% vs 17.4%, P<0.01). But it was not significantly different between VVS group and POTS group (P>0.05). The sensitivity, specificity and diagnostic coincidence of ambulatory blood pressure pattern to NMS was 66.0%, 82.6% and 71.4%, respectively.

There was autonomic nerve adjustment imbalance in children with NMS. And the diagnostic value of ambulatory blood pressure pattern to children with NMS was high.