ABSTRACT
Objective: To investigate the dynamic electrocardiogram (ECG) changes of head-up tilt test in patients with suspected vasovagal syncope. Methods: A total of 502 outpatients of our hospital with suspicious vasovagal syncope from 2015-08 to 2016-12 were enrolled. All patients received head-up tilt test with synchronization of 12 lead ECG. Based on head-up tilt test result, the patients were divided into 2 groups: Positive group,n=244 and Negative group,n=258. The P wave duration, corrective QT (QTc) duration and P wave axis in ECG were compared between 2 groups. Results: Compared with Negative group, Positive group had the longer P wave duration (95.65±38.50) ms vs (88.61±17.09) ms,P<0.05; P wave axis was right shifted before syncope (69.87±18.18)° vs (66.82±16.51)° , while left shifted during syncope (62.87±25.39)° vs (68.47±15.30)° and after syncope (56.87±22.45)° vs (68.49±16.35)°, allP<0.05; the shorter QTc duration before syncope (418.69±92.35) ms vs (435.76±59.29) ms,P<0.05. Conclusion: The patients with vasovagal syncope had some speciifc ECG features during head-up tilt test including P wave duration, P wave axis and QTc duration, those may play certain forewarning function for vasovagal syncope onset.