Analyzing the correlation between iduced syncope in head-up tilt test and recurrence of syncope in vasovagal syncope patients

Objective To analyze the correlation between induced syncope in head-up tilt test (HUTT) and recurrence of syncope in vasovagal syncope (VVS) patients by follow-up. Methods This study was based on the data from a total of 214 outpatients or inpatients with positive HUTT undergone in Ningbo First Hospital from April 2016 to June 2018 and diagnosed with VVS. Cases were divided into a non-syncope group (consciousness) and a syncope group (loss of consciousness) . The baseline information, blood pressure and heart rate and arrhythmic events in HUTT and the Vasovagal Syncope International Study (VASIS) type incidence were analyzed and compared between the two groups. The recurrence rate of syncope was also compared between the two groups and among each VASIS type under the natural condition during follow up from 6 to 32 months. Results There were 118 cases in the non-syncope group and 96 cases in the syncope group. The rate of blood pressure values of 0/0 mmHg, abnormal electrocardiogram and the VASIS type 2B in the syncope group were significantly higher than that in the non-syncope group (80.2% vs. 66.9%, 18.8% vs. 8.5%, 7.3% vs. 0.8%, all P 0.05) or between the VASIS positive type (type 1, 13.2% vs. 7.8%, type 3, 12.2% vs. 13.0%, type 1 +type 2, 13.2% vs. 11.7%, all P>0.05) , and there was no recurrence of syncope in VVS patients with type 2 in the non-syncope group. Binary logistics regression analysis showed that all possible related factors diabetes (OR=0.530) , basal heart rate (OR=0.999) , natural course of disease (OR=1.518) , abnormal electrocardiogram (OR=0.774) , VASIS 1 (OR=0.586) , VASIS 2A (OR=0.374) , VASIS 2B (OR=0.798) , VASIS 3 (OR=1.000) , blood pressure 0/0 mmHg (OR=0.662) , duration of blood pressure drop (OR=1.014) could not predict spontaneous recurrence of syncope (P>0.05) . Conclusion There was no correlation between induced syncope in HUTT and spontaneous recurrence of syncope in VVS patients with positive HUTT. Key words: Syncope; Syncope, vasovagal; Head-up tilt test