Analysis Of Factors Related The Positive Results Of Head Up Tilt Test

Objective:The purpose of this study was to investigate the factors affecting the positive results of head-up tilt test(HUTT)in patients with vasovagal syncope(VVS).Methods:This study included the clinical data of 160 patients with suspected VVS from October 2017 to October 2019,including 74 males(46.3%)and 86 females(53.8%).The median spells of syncope was 3(1-4 quartiles).All patients were examined by HUTT.According to the results of HUTT,the patients were divided into HUTT positive group and HUTT negative group.The effects of clinical characteristics,anxiety score,depression score,QRS voltages of 12-lead Electrocardiogram(ECG),left ventricular end-diastolic diameter,heart rate variability,diabetes mellitus,and hypertension on the results of HUTT were analyzed.Among them,the clinical features include the patient’s sex,age,syncope duration,and the number of syncope and syncope spells in the past two years.The anxiety and depression scores of the patients were calculated by filling in the generalized anxiety disorder-7(GAD-7)and the patient health questionnaire-9(PHQ-9).The QRS voltages in 12 leads of electrocardiogram was measured in mV unit.The lowest QRS voltage in 12 leads(QRSmin),the highest QRS wave voltage in(QRSmax),and the sum of QRS voltages in limb lead and chest lead were calculated respectively.24-hour ambulatory electrocardiogram heart rate variability(HRV),including the standard deviation of 24-hour R-R interval(SDNN),the standard deviation of the average R-R interval(SDANN),and the square root of the mean squared differences of successive R-R intervals(rMSSD).The effects of the above clinical factors on the positive results of HUTT were compared.Results:1.1 A total of 160 patients were included in this study,including 74 males(46.3%)and 86 females(53.7%).There were 87 HUTT positive cases(54.4%),including 48 cases of mixed type,38 cases of vascular inhibition type,1 case of cardiac inhibition type and 73 cases of HUTT negative(45.6%).The difference of HUTT positive rate between female and male patients in HUTT positive group and negative group was statistically significant(P<0.05).1.2There were 57 patients with≥3 syncope episodes in the HUTT positive group and 28 patients with≥ 3 syncope episodes in the,HUTT negative group(42.4%)There was a significant difference in the positive rate of HUTT between the two groups(P<0.01),and the difference was statistically significant.The left ventricular end-diastolic diameter of HUTT positive group was 44.98 ±3.80mm,and the mm,HUTT negative group was 46.66±3.11mm.There was significant difference between the two groups(P<0.01).2 Analysis of prodromal symptoms in patientsAmong the 160patients,146patients(91.3%)had prodromal symptoms,and 81 cases were HUTT positive group(93.1%),HUTT negative group 62 cases(84.9%).The main manifestations were chest tightness,dizziness,palpitation,sweating,blurred vision,fatigue,nausea,shortness of breath,tinnitus,fever,pallor,pain and no prodromal symptoms.There was no significant difference in prodromal symptoms between HUTT positive group and HUTT negative group(P>0.05),but there was significant difference in nausea and fatigue between HUTT positive group and HUTT negative group(P<0.05).3 Analysis of 12 leads ECG in patients71 patients(44.4%)showed single-lead QRS wave low voltage(QRS<0.4mV)in limb leads,36 patients(50.7%)showed aVL lead,and others showed low-voltage lead Ⅰ(36.5%),Ⅲ lead(5.6%),aVF lead(5.6%),aVR lead(3%).Compared with the HUTT negative group,the limb lead single lead QRS wave low voltage HUTT positive group was significantly higher than the HUTT negative group,51 cases(58.6%)and 20 cases(27.4%),respectively.Compared with the negative group,the difference was statistically significant.And the QRSmin in the HUTT positive group was significantly lower than that in the HUTT positive group,and the difference was statistically significant.The results of receiver operating characteristic(ROC)curve analysis showed that QRSmin<0.4mv was differentiated between HUTT positive group and HUTT negative group,with a sensitivity of 71%and specificity of 58%,area under the curve(AUC)=0.579.4 Comparison of heart rate variability between HUTT positive and negative groupsSDNN and rMSSD in HUTT positive group were higher than those in HUTT negative group,and there was no significant difference.SDANN in HUTT positive group was higher than that in HUTT negative group(132.69±29.51vs111.63±38.74),the results were statistically significant(P=0.01).5 Comparison of anxiety and depression between HUTT positive group and HUTT negative groupsThe rank sum test of anxiety degree in HUTT positive group was significantly higher than that in HUTT negative group(93.36 vs 65.18,P<0.001).The rank sum test of depression degree in HUTT positive group was significantly different from that in HUTT negative group(95.10 vs 63.78,P<0.001).6 Logistic regression analysis resultsAccording to the results of single factor analysis of variance,rank sum test and t-test,the indexes which had significant influence on the positive rate of HUTT were analyzed by Logistics regression analysis.the factors that had significant influence on the results of HUTT were anxiety,SDANN,syncope≥ 3 times,sex,nausea,fatigue,low voltage of QRS wave in limb lead(<0.4mV).Conclusion(s):1 Gender,syncope times≥3 times,nausea,fatigue,limb lead QRSmin and isolated low voltage QRS<0.4mV,SDANN,left ventricular end diastolic diameter,anxiety score and depression score were predictive of positive results of head-up tilt test in patients with vasovagal syncope2 Anxiety,SDANN,syncope times≥3 times,sex,nausea,fatigue,limb lead single lead QRS wave voltage<0.4mV can be used as independent predictors of positive results of head-up tilt test.3 Low voltage of QRS wave in limb lead<0.4mV may play an important role in early diagnosis and treatment of vasovagal syncope and further understanding of the pathogenesis of vasovagal syncope.