title: Effects of the menstrual cycle phases on the tilt testing results in vasovagal patients.
abstract: OBJECTIVE
  The aim of the study was to assess the distribution of positive tilt testing (TT) throughout the menstrual cycle and to determine if the phase of menstrual cycle contributes to the duration of the loss of consciousness.
  
  
  METHODS
  TT results of 183 premenopausal women, aged 29.5 ± 9.8 years, were studied. The menstrual cycle was divided into four phases based on the first day of the last menstrual bleeding: perimenstrual (M), preovulatory (F), periovulatory (O) and postovulatory (L).
  
  
  RESULTS
  Positive TT results were equally distributed. In patients with TT in O phase, the highest percentage of NTG provocation was needed. Patients in L phase had significantly lower incidence of cardioinhibitory reaction. The longest duration of loss of consciousness was in the M phase. Multiple regression analysis revealed that the duration of loss of consciousness during positive TT was significantly associated with higher number of syncopal events, TT performed in M phase and lower heart rate at TT termination. Cardiodepressive type of neurocardiogenic reaction was more frequent during M and O phase than during L phase.
  
  
  CONCLUSIONS
  The distribution of positive TT results as well as syncope and presyncope does not differ throughout the menstrual cycle. Diagnostic TT in premenopausal women with unexplained syncope could be performed irrespective of the phase of menstrual cycle. TT has similar sensitivity throughout the menstrual cycle. During the postovulatory phase, cardioinhibitory reaction is less frequent than in M and O phases. The duration of loss of consciousness is longer during the M phase of the menstrual cycle independently of the higher syncope number and lower heart rate at TT termination.
authors.affiliation: Teaching Department for Emergency Medical Services, Wroclaw Medical University, Bartla 5, 51-618 Wrocław, Poland. dzysko@wp.pl
authors.forename: Dorota
authors.initials: D
authors.lastname: Zyśko
authors.forename: Jacek
authors.initials: J
authors.lastname: Gajek
authors.forename: Lukasz
authors.initials: L
authors.lastname: Terpiłowski
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Agrawal
authors.forename: Paweł
authors.initials: P
authors.lastname: Wróblewski
authors.forename: Jerzy
authors.initials: J
authors.lastname: Rudnicki
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008597:Menstrual Cycle / Q000502:physiology*; D012680:Sensitivity and Specificity; D019462:Syncope, Vasovagal / Q000175:diagnosis*; D018667:Tilt-Table Test; D055815:Young Adult