ABSTRACT
Objective:To investigate the difference of heart rate variability in cardioinhibitory type vasovagal syncope(VVS-CI) children with different body mass index(BMI).Methods:Clinical data of thirty-four children with syncope or pre-syncope were retrospectively analyzed, who visited specialist clinic for syncope and diagnosed as VVS-CI at the Second Xiangya Hospital of Central South University from January 2012 to December 2019.BMI was calculated based on height and weight, and divided into lean group(BMI≤18.4 kg/m 2, n=19) and normal group(BMI 18.5-23.9 kg/m 2, n=15). Heart rate variability(HRV) of 24 h dynamic electrocardiogram was analyzed using linear analysis method.Time domain index included SDNN, SDANN, rMSSD and pNN50.Frequency domain index included total power(TP), ultra low frequency power(ULF), very low frequency power(VLF), low frequency power(LF), high frequency power(HF) and LF/HF. Results:There was no significant difference in SDNN, SDANN and rMSSD between lean and normal group( P>0.05), but pNN50 increased in lean group( P<0.05). No significant differences were found in TP, ULF, LF, HF and LF/HF between two groups( P>0.05), while VLF was lower in lean group than that in normal group( P<0.05). There was no statistical difference in time domain index and frequency domain index between different gender between lean and normal group( P>0.05). SDNN, SDANN and LF were higher in<12 years old than those in≥12 years old in lean group( P<0.05). There was no statistical difference in rMSSD, pNN50, TP, ULF, VLF, HF and LF/HF( P>0.05). ULF increased and LF decreased in<12 years old compared to ≥12 years old in normal group( P<0.05). No statistical differences were found in SDNN, SDANN, rMSSD, pNN50, TP, VLF, HF and LF/HF( P>0.05). Conclusion:The autonomic nervous regulation function of VVS-CI children with low BMI and normal BMI is different, resulting in HRV difference.There were also differences in HRV between<12 years old and ≥12 years old with the same BMI.
ABSTRACT
Objective:To investigate the relationship between body mass index (BMI) and response time of cardioinhibitory type vasovagal syncope (VVS-CI) in children.Methods:The clinical data of 56 children with syncope or pre-syncope were retrospectively analyzed and they visited specialist clinic for syncope and were diagnosed as VVS-CI in the Second Xiangya Hospital, Central South University from December 2012 to September 2019.Based on height and weight, BMI was calculated, and divided into low BMI group (35 cases) and normal BMI group (21 cases). Between the 2 groups, baseline heart rate, head-up tilt test (HUTT) positive response heart rate, baseline head-up tilt test (BHUT) positive response time, and sublingual nitroglycerin-provocated HUTT (SNHUT) positive response time were compared.The correlation between BMI and positive response time was analyzed.SPSS 22.0 software was applied for statistical analysis.Results:There were no significant differences in age, sex, duration of disease and number of syncope between the 2 groups (all P>0.05). No significant differences were found in baseline heart rate and positive response heart rate between the 2 groups [(78.5±15.3) times/min vs.(72.8±8.7) times/min, t=1.223, P=0.230; (44.0±13.9) times/min vs.(47.0±10.0) times/min, t=-0.664, P=0.511]. Compared with normal BMI group, BHUT positive patients/SNHUT positive patients were higher in low BMI group (27/8 cases vs.9/12 cases, χ2=4.839, P=0.027), and the positive response time of BHUT was shorter [(13.1±4.6) min vs.(23.7±9.5) min, t=-2.691, P=0.023]. There were no significant differences in SNHUT positive response time between the 2 groups ( P>0.05). Low BMI was correlated with BHUT positive response time ( r=0.750, P=0.005). Normal BMI was not associated with BHUT positive response time ( r=0.316, P=0.217). There was no correlation between low BMI and normal BMI and SNHUT positive response time ( r=0.177, P=0.431; r=0.021, P=0.940). Conclusions:Low BMI is positively correlated with BHUT positive response time of children with VVS-CI.The time it takes for syncope occurrence was shorter in children with low BMI than that in normal BMI.