Dynamic Variation Of Synchronization 12 Lead Electrocardiogram P Wave And QRS Wave And T Wave Amplitude In Vasovagal Syncope Children During Head-up Tilt Test

Objective To investigate dynamic variation of synchronization 12 lead electrocardiogram(12ECG)P wave,QRS wave,T wave amplitude in vasovagal syncope(VVS)children during head-up tilt test(HUTT).Methods Ninety-six children(40 males,56 females,age 4-17 yrs, mean 11.24±3.41yrs)were enrolled in this study,who came from children syncope outpatient department or in-patient department of the Second Xiangya Hospital of Central South University during Oct 2006 to Oct 2007.According to the result of HUTT they were further divided into HUTT- positive group(23 males,34 females,mean age 12.11±2.97yrs)and HUTT-negative group(17 males,22 females,mean age 9.96±3.64yrs).Twenty- eight healthy children were as control group, who were matched in age and gender(12 males,16 females,mean age 10.64±2.46 yrs).All children experienced HUTT and were monitored dynamically by 12 ECG.All data preserved in computer according to clinical samples.Playback and analysis all data after test,SPSS 11.0 software was used for the statistical analysis of these data.Resultâ‘ Among 57 HUTT-positive children,13 samples onset at baseline head-up tilt test(BHUT),mean time 24.62±5.94 minutes, while other samples onset at sublingual nitroglycerin head-up tilt table test(SNHUT),mean time 5.27±1.89 minutes.â‘¡P wave amplitude of group at 1 minutes SNHUT stage inâ… ,aVL,aVF lead were significantly increased than HUTT-negative group(p＜0.05).â‘¢QRS wave amplitude had no significant difference between syncope group and healthy control group at baseline,and the starting of tilt,and 5-minutes tilt(p＞0.05).While QRS wave amplitude of syncope group at others time were significantly reduced than control group(p＜0.05)in some lead,for example aVR,V₂,V₃ and V₄ lead.â‘£QRS wave amplitude of HUTT-positive group in V₃ and(or)V₄ lead were significantly reduced than HUTT- negative group at 35-minutes of BHUT,and 45- minutes of BHUT,and 5- minutes of SNHUT,and 6-minutes of SNHUT(p＜0.05).⑤T wave and ST segment amplitude of syncope group were significantly reduced than healthy control group in some lead(V₃,V₄,V₅ and V₆ lead)(p＜0.05).And T wave and ST segment amplitude of HUTT-positive group were significantly reduced than HUTT-negative group in some lead(â…¡,â…¢,aVR,aVL,aVF and V₆ lead)about at the onset of symptoms(p＜0.05).â‘¥P wave duration, QRS duration,QT duration of VVS children at the onset of symptoms were significantly reduced compared to at baseline(pa＜0.05).P wave duration of VVS children at the onset of symptoms were at the start of tilt(p＜0.05).There were no significant difference of these indexes at 5-minutes of BHUT(pa＞0.05).QT duration was significantly shorten compared to the end of test(p＜0.05). Conclusionâ‘ P wave amplitude of lower wall in limb lead of HUTT-positive children was significantly increased at the start of SNHUT stage compared to HUTT-negative group and P wave duration at the onset of symptoms was significantly decreased compared to baseline and the start of tilt(pa＜0.05).â‘¡QRS wave amplitude of VVS children was significantly reduced than healthy children in right chest lead and QRS duration at the onset of symptoms was significantly decreased compared to baseline(pa＜0.05).â‘¢T wave and ST segment amplitude of VVS children are significantly reduced than healthy children during HUTT,and T wave and ST segment amplitude of HUTT-positive children are significantly reduced than HUTT- negative children with unexplained syncope(UPS)history.â‘£QT duration of VVS children was significantly shorten compared to baseline and the end of tilt(p＜0.05).In a word,the cardiac autonomic nervous function is abnormal of VVS children,and T wave and ST segment amplitude changes are more sensitive than that of P wave and QRS wave of 12 ECG.