Diagnosis Of Head-up Tilt Table Test And The Intervention Effect Of Midodrine Hydrochloride In Children With Vasovagal Syncope

Objective To carry out head-up tilt table test evaluation and influential factor analysis in children with vasovagal syncope(VVS),to explore the initial relation between VVS of children and blood serum insulin,C-peptide,blood or uric electrolytes,and to study the intervention effect and mechanisms of midodrine hydrochloride and metoprolol in children with VVS.Methods The study involved a group of 301 chilren[125 males and 176 females,aged 3.08-18 years,mean(11.82±3.16)years)]with unexplained syncope or presyncope in out-patient clinic of syncope in the Second Xiangya Hospital of Central South University between January 2001and April 2007 and 27 healthy children as control groupe.To choose baseline head-up lilt table test(HUTT)and sublingual nitroglycerin tilt test(SNHUT)as empirical method and monitore heart rate,systolic pressure and diastolic pressure at all time points.To detect baseline blood serum insulin(INS),C-peptide(CP),fasting plasma glucose(FPG), plasma renin activity(PRA),angiotensinⅡ(ATⅡ),aldosterone(ALD) and blood or uric electrolytes for children with syncope(n=79)between June 2004 and April 2007.The children with syncope between January 2003 and April 2007 were selected and given randomly midodrine hydrochloride and metoprolol for treatment at the base of non-drug treatment.The computer did statistic analysis for the detected data by SPSS 11.5 software. Results①The positive rate was 23.92%in BHUT,it improved to 57.81%when cite SNHUT.Mean time of syncope episode were (22.54±10.82)min in BHUT and(5.47±2.78)min in SNHUT.There were no differences in response types between BHUT and SNHUT (p>0.05).②During HUTT,there was no significant relation between the change of heart rate,systolic pressure or diastolic pressure and subjects age,sex,tilt angles or clinical syncope frequency(p>0.05 at most of time points).The change of hemodynamics at the end of test in positive response was not related with whether or not stimulated by nitroglycerin (p>0.05).With frequency increasing,syncope episode time was increasing progressively,heart rate decreasing,and both systolic pressure and diastolic pressure increasing progressively(p>0.05).③There were no differences in sex,age,dizziness and syncope among response types of positive HUTT.④Among the group which was positive in HUTT,blood kalium decreased while blood calcium rose(p<0.05),as well as 24h uric natrium and uric kalium increased significantly(p<0.05),PRA and AⅡincreased(p>0.05),whereas FPG decreased(p<0.05),INS and CP and ALD also lowered(p>0.05).⑤Among the group with syncope,blood kalium and phosphonium decreased,blood calcium rose(p<0.01)in female;whereas FPG and ALD reduced(male > female,p<0.05),INS and CP decreased(male < female,p>0.05).⑥Among the grope with sycope,the patients above 12 years compared with below had the same increase in INS(p<0.05)and in CP(p>0.05).⑦No differences of syncope frequency was seen in serum electrolytes,24h uric electrolytes, electrolytes of each millilitre urine,and the ratio between serum and uric electrolytes(p>0.05);The groupe with syncope frequency below 4 times compared with above 4 times had a significant rise in FPG(p<0.05)and a slight increase in INS and CP(p>0.05).Negative correlation was present between syncope frequency and INS and CP(r=-0.635 and -0.576).⑧Comparing HUTT before and after midodrine hydrochloride and metoprolol:after treatment as compared to before,heart rate slightly increased in the group with midodrine hydrochloride treatment and decreased in the group with metoprolol treatment at all time points of HUTT(p>0.05),whereas both two groups had a slight decrease in systolic pressure(p>0.05)and in diastolic pressure at each time point of BHUT(p>0.05).Furthermore,metoprolol group present a trend of increase with tilt time lasting at every time points of SNHUT(p>0.05).⑨Judgement of clinical effect:In 23 children with VVS after administration of midodrine hydrochloride for 15-125 days(mean 53.52±40.20 days),effective rate were 73.91%(17/23),and side effect was not seen;In 28 children with VVS after administration of metoprolol for 3-148 days(mean 38.61±32.68 days),effective rate were 89.29% (25/28)and 10.71%cases had side effect.there were no significant differences between two groups on curative effect.To judge curative effect according to HUTT:In 23 children with VVS after administration of midodrine hydrochloride for 15-125 days(mean 55.24±40.29 days), effective rate were 54.54%(12/22);In 24 children with VVS after administration of metoprolol for 3-148 days(mean 43.71±43.17 days), effective rate were 70.83%(17/24).there were significant differences between two groups(p<0.05).At the end point of HUTT,the time of syncope episode after treatment of midodrine hydrochloride prolonged slightly in BHUT(p>0.05),while shorten slightly in SNHUT(p>0.05),as well as heart rate,systolic pressure and diastolic pressure decreased slightly(p>0.05).The time of syncope episode after treatment of metoprolol shorten slightly "in HUTT(p>0.05),as well as heart rate increased slightly(p>0.05),systolic pressure and diastolic pressure decreased slightly(p>0.05).⑩After treatment of midodrine hydrochloride,no marked changes were seen in liver function,renal function,blood fat and blood or uric electrolytes(p>0.05),whereas FPG and PRA decrease,at the same time INS,CP,AⅡand ALD all increased (p>0.05).Conclusion①HUTT is an available tool to evaluate children autonomic function.②In the children with VVS autonomic function disorder and sympathetic and parasympathetic function overbalance.In clinical,part of the children with VVS fall ill because of unexplained dizziness.③Hemodynamic variation caused by HUTT has no correlation with age,sex tilt angle and clinical syncope frequency,and hemodynamics at tilt end point do not relate obviously with whether or not stimulated by nitroglycerin.Thus HUTT has no predictive value for children VVS.④The program with 60°tilt angle and 45min time is preferred to children HUTT,and sublingual administration of nitroglycerin acted as provocative factor is convenient and safe and reproducible.⑤INS and CP take part in possibly development of VVS.⑥There is no significant relation between blood or uric electrolytes and baseline condition of VVS.⑦Differences are not seen between metoprolol and midodrine hydrochloride for children VVS in clinical effect,whereas,effective rate of metoprolol was larger in HUTT evaluating it,that show HUTT outweigh subjective effect in judgement of curative effect for children VVS.⑧The mechanisms of midodrine hydrochloride treatment for children VVS have possibly correlation with elevating INS and CP,lowering PRA and increasing ALD and AⅡ,but have no close relation with blood or uric electrolytes.⑨Midodrine hydrochloride has no marked effect on liver and renal function and blood-fat metabolism of children,so it is safe for children to use. Objective To evaluate and analysis influential factor of head-up tilt table test in children with vasovagal syncope(VVS).Methods The study involved a group of 301 chilren[125 males and 176 females,aged 3.08-18 years,mean(11.82±3.16)years]with unexplained syncope or presyncope in the Second Xiangya Hospital of Central South University between January 2001 and April 2007 and 27 healthy children as control group.To choose baseline head-up lilt table test(HUTT)and sublingual nitroglycerin tilt test(SNHUT)as empirical method.To monitore heart rate,systolic pressure and diastolic pressure at all time points and compare result of the children with syncope according to following groups:①Syncope group(n=301)and control group (n=27);②HUTT positive group(n=174)and HUTT negative group (n=127);③HUTT positive group with vasodepressor response (n=139)and those cardioinhibitory response + mixed response (n=139);④In syncope group,the group with 60°tilt angle in HUTT (n=150)and the group with 70°(n=151);⑤According to age,syncope group was divided into the group below 12 years(n=125)and the other above 12 years(n=176);⑥According to sex,syncope group was divided into male(n=125)and female(n=176)two groups;⑦According to syncope frequency,syncope was divided intoⅠgroup (frequency was 1 time,n=43),Ⅱgroup(frequency was 2-4 times,n=124) andⅢgroup(frequency=5 times,n=56);⑧The group with unexplained dizziness(n=76)and the group with unexplained syncope(n=225);⑨BHUT positive group(n=72)and SNHUT positive group(n=102). The computer did statistic analysis by SPSS 11.5 software.Results①The positive rate was 23.92%in BHUT,it improved to 57.81%when cite SNHUT.Mean time of syncope episode were (22.54±10.82)min in BHUT and(5.47±2.78)min SNHUT.There were no differences in response types between BHUT and SNHUT(p>0.05).②During HUTT,there was no conspicuous relation between the change of heart rate,systolic pressure or diastolic pressure and subjects age,sex, tilt angles or clinical syncope frequency(p>0.05 at most of time points). The change of hemodynamics at the end of test in positive response was not related with whether or not stimulated by nitroglycerin(p>0.05).With frequency increasing,syncope episode time was increasing progressively, heart rate decreasing by degrees,and both systolic pressure and diastolic pressure increasing progressively(p>0.05).The optimal regression equation for syncope frequency estimated:syncope frequency(times)= 1.553+0.204×age(years).③There were no differences in sex,age, dizziness and syncope among response types of HUTT.④HUTT positive rate of dizziness group and syncope group was 63.16%and 56.00% respectively,and during HUTT,heart rate was faster in the former than the latter(p<0.05 or 0.01 at most of time points),systolic pressure lower and diastolic pressure higher(p>0.05).At the end point of HUTT,heart rate(p<0.05),systolic pressure and diastolic pressure(p>0.05)present that dizziness group was larger than syncope group.The time of syncope episode in the former was longer than the latter(p>0.05).Conclusion①HUTT is an available tool to evaluate children autonomic function.②In the children with VVS autonomic function disorder and sympathetic and parasympathetic function overbalance.In clinical,part of the children with VVS fall ill because of unexplained dizziness.③Hemodynamic variation caused by HUTT has no correlation with age,sex,tilt angle and clinical syncope frequency,and hemodynamics at tilt end point do not relate obviously with whether or not stimulated by nitroglycerin.Thus HUTT has no predictive value for children VVS.④The program with 60°tilt angle and 45min time is preferred to children HUTT,and sublingual administration of nitroglycerin acted as provocative factoris convenient and safe and reproducible. Objective To explore the initial relation between VVS of children and blood serum insulin,C-peptide,blood and uric electrolytes.Methods HUTT was performed in a group of 79 children with unexplained syncope or presyncope(syncope group,n=79)and healthy children(control group,n=11)in out-patient clinic of syncope in the Second Xiangya Hospital of Central South University between June 2006 and April 2007.To detect baseline insulin(INS),C-peptide(CP),fasting plasma glucose(FPG),plasma renin activity(PRA),angiotensinⅡ(ATⅡ),aldosterone(ALD)and blood and uric electrolytes.To compare result of syncope group according to following groups:①with control group;②among various types of HUTT positive response;③among different results of HUTT positive response;④between males and females;⑤among different age;⑥among different syncope frequency. The computer did statistic analysis by SPSS 11.5 software.Results①Syncope compared with control group,blood kalium decreased while blood calcium rose(p<0.05);24h hypourocrinia,uric natrium,uric kalium,uric chlorinum,uric calcium and uric phosphonium increased while uric magnesium decreased(p>0.05);uric natrium and uric calcium of each millilitre urine increased(p<0.05 or 0.01);the ratio of blood natrium to blood kalium rose(p<0.05);FPG,INS,CP and ALD cut down,whereas PRA and AⅡincreased(p>0.05).②In the children with syncope,HUTT positive group compared with HUTT negative group and control group,blood kalium decreased while blood calcium rose(p<0.05);24h urinary volume raise(p>0.05),as well as 24h uric natrium and uric kalium increased significantly(p<0.05),and 24h uric chlorinum,uric calcium and uric magnesium increased slightly increased (p>0.05),there was the same trend of change between uric electrolytes of each millilitre urine and 24h ones;Both the ratio of blood natrium to blood kalium and that of uric natrium to serum creatinine increased (p<0.05);whereas FPG decreased(p<0.05),INS,CP and ALD also drop(p>0.05),but PRA and AⅡincreased(p>0.05).③In the children, HUTT positive reaction type with vasodepressor response(n=139) compared with those cardioinhibitory response + mixed response,no differences was seen in serum electrolytes,electrolytes of 24h uric each millilitre urine between two groups(p>0.05);PRA decreased obviously in the former while increased significantly in the latter(p<0.01).④Comparing males with females:female blood kalium and blood phosphonium decreased while blood calcium increased(p<0.01); differences were not seen in electrolytes of each millilitre urine and ratio of electrolytes between two groups(p>0.05);FPG and ALD drop(male > female,p<0.05)while INS and CP decreased(male < female,p>0.05).⑤Comparing different age:the groups below and above 12 years compared with control group,the change in serum electrolytes was not marked(p>0.05),24h urinary volume,uric natrium,uric kalium,uric calcium,uric chlorinum and uric phos- phonium were higher in the group above 12 years than below ones(p>0.05),there was the same trend of change between uric natrium and uric chlorinum of each millilitre and 24h uric electrolytes(p>0.05),the syncope group above 12 years compared with that below 12 years,INS(p<0.05)and CP(p>0.05) increased.⑥Comparing various syncope frequency:no differences of syncope frequency was seen in serum electrolytes,24h uric electrolytes, electrolytes of each millilitre urine,and the ratio between serum and uric electrolytes(p>0.05);the groupe with syncope frequency below 4 times compared with above 4 times had a significant rise in FPG(p<0.05)and a slight increase in INS and CP(p>0.05).negative correlation was present between syncope frequency and INS and CP(r=-0.635 and -0.576).the optimal regression equation for syncope frequency estimated:syncope frequency(times)= 4.565-0.213×insulin(mul/L).Conclusion①INS and CP take part in possibly development of VVS.②There is no significant relation between blood or uric electrolytes and baseline condition of VVS. Objective To study the intervention effect and mechanisms of midodrine hydrochloride and metoprolol in the children with vasovagal syncope(VVS).Methods In a group of 51 chilren[17 males and 34 females,aged 6.92-18 years,mean(11.95±2.56)years]with unexplained syncope in the Second Xiangya Hospital of Central South University between January 2003 and April 2007,there were 46 cases that were positive in HUTT. Given randomly midodrine hydrochloride[n=22,dose 1.0-1.5mg/(kg.d), po,Bid]and metoprolol[n-24,dose 1.0-1.5mg/(kg.d),po,2-3 times/day] for treatment at the base of non-drug treatment.To compare hemodynamics before and after treatment of midodrine hydrochloride and metoprolol;Also to compare liver function,renal function,blood fat and blood electrolytes,INS,CP,PRA,AⅡ,24h uric electrolytes and electrolytes of each millilitre urine before and after treatment of midodrine hydrochloride.The computer did statistic analysis by SPSS 11.5 software.Results①Comparing HUTr before and after midodrine hydrochloride and metoprolol:after treatment as compared to before, heart rate slightly increased in the group with midodrine hydrochloride treatment and decreased in the group with metoprolol treatment at all time points of HUTT(p>0.05),whereas both two groups had a slight decrease in systolic pressure(p>0.05)and in diastolic pressure at each time point of BHUT(p>0.05).Furthermore,the latter present a trend of increase with tilt time lasting at every time points of SNHUT(p>0.05).②Judgement of clinical effect:In 23 children with VVS after administration of midodrine hydrochloride for 15-125 days(mean 53.52±40.20days),effective rate were 73.91%(17/23),and side effect was not seen;In 28 children with VVS after administration of metoprolol for 3-148 days(mean 38.61±32.68 days),effective rate were 89.29% (25/28)and 10.71%cases had side effect.There were no significant differences between two groups on curative effect.To judge curative effect according to HUTT:In 23 children with VVS after administration of midodrine hydrochloride for 15-125 days(mean 55.24±40.29 days), effective rate were 54.54%(12/22);In 24 children with WS after administration of metoprolol for 3-148 days(mean 43.71±43.17 days), effective rate were 70.83%(17/24).There were significant differences between two groups(p>0.05).At the end point of HUTT,the time of syncope episode after treatment of midodrine hydrochloride prolonged slightly in BHUT(p>0.05),while shorten slightly in SNHUT(p>0.05),as well as heart rate,systolic pressure and diastolic pressure decreased slightly(p>0.05).The time of syncope episode after treatment of metoprolol shorten slightly during HUTT(p>0.05),heart rate increased slightly(p>0.05),whereas systolic pressure and diastolic pressure decreased slightly(p>0.05).③After treatment of midodrine hydrochloride,no marked changes were seen in liver function,renal function,blood fat and blood or uric electrolytes(p>0.05),whereas FPG and PRA decrease,at the same time INS,CP,AⅡand ALD all increase (p>0.05).Conlusion①Differences are not seen between metoprolol and midodrine hydrochloride for children VVS in clinical effect,whereas, effective rate of metoprolol is larger in HUTT evaluating it,that show HUTT outweigh subjective effect in judgement of curative effect for children with VVS.②The mechanisms of midodrine hydrochloride treatment for children with VVS have possibly correlation with elevating INS and CP,lowering PRA and increasing ALD and AⅡ,but has no close relation with blood or uric electrolytes.③Midodrine hydrochloride has no marked effect on liver and renal function and blood-fat metabolism of children,so it is safe for children to use.