Evaluation Of The Affects For Heart Rate Variability In Clinical Diagnosis Of Vasovagal Syncope

Objective:Vasovagal syncope as a common clinical emergency,due to the complexity of the cause and increasing rate in recent years,becomes the attention of scholars at home and abroad as the main object of research,vasovagal syncope(VVS)is the most common type of syncope,accounting for about 50%of the total.Automatic nerve function is abnormal that is the main mechanism of vasovagal syncope,clinical head-up tilt test(head-up tilt test,HUTT)examination is the main method for the diagnosis of vasovagal syncope(VVS),head-up tilt test inspection need induce symptom reproduction of patients with syncope,which has some risks,and is relatively cumbersome.Heart rate variability(HRV)analyze the subtle differences between the continuous sinus rhythm,indirect response to sympathetic nerve and vagus nerve function of dynamic balance,to evaluate autonomic nerve function as one of the bettest means which has the advantages of simple operation,better repeatability.Vasovagal syncope(VVS)main mechanism is sure of abnormal autonomic nervous function,but the function of autonomic nervous system during asymptomatic was riported not much,the main content of my topic is to study autonomic nervous function of vasovagal syncope(VVS)patients during the without symptoms state,and to explore the new and small risk method of diagnosis of vasovagal syncope.We select the real clinical patients as the research object,throught comparing the 24h heart rate variability of the difFerente groups in asymptomatic to understand the autonomic nervous system function of vasovagal syncope in asymptomatic period,and to evaluate the diagnostic value of heart rate variability for vasovagal syncope..Methods:In our hospital patients with unexplained syncope are selected 60 cases,the selected patients except syncope without any other diseases,who were detailed inquiry,carefuliy investigated,underwent comprehensive and reasonable auxiliary examination all weren't to be find identify the syncopal clear organic reasons,so all were diagnosed unexplained syncope.The selected 60 patients with unexplained syncope patients underwent tilt test,divided into two groups:positive group is vasovagal syncope group(VVS group);negative group is non vascular vasovagal syncope group(non VVS group).At the same time,28 cases were matched with the negative reults of upright tilt test,and the healthy persons without any disease were defined as third groups(healthy group).Three groups of subjects were performed 24h dynamic electrocardiogram(DCG)examination without any abnormal symptoms period,conted 24h HRV time domain and frequency domain index from the 24h DCG.Compared 24 h HRV time domain and frequency domain index of each two groups in the three groups,P<0.05,there was a statistically significant.Results:After comparison,it is concluded that 24-hour heart rate variability in time domain and frequency domain index value of VVS group SDNN,SDNNi,pNN50,RMSSD,TP,HF compared with healthy group was significantly lower,(P<0.05);24hHRV time domain and frequency domain index of VVS group SDNN,SDNNi,rMSSD and PNN50,TP,VLF,LF,HF compared with non VVS group in the indexes were significantly lower,(P<0.05);non VVS group 24hHRV each indexes have no significant difference with the healthy group,and P>0.05 Conclusion:In asymptomatic period autonomic nervous function of patients with vasovagal syncope also exist abnormal,in some cases without inducing syncope,the 24-hour heart rate variability can provide evidence for the diagnosis of vasovagal syncope(VVS).