title: Amnesia for loss of consciousness is common in vasovagal syncope.
abstract: OBJECTIVE
  The aim of this study was to determine the prevalence of amnesia for loss of consciousness (A-LOC) in those who have a history suggestive of vasovagal syncope (VVS) and who develop syncope on head-up tilt (HUT) table testing. Furthermore, we wished to determine if A-LOC is an age-dependent phenomenon in VVS and whether haemodynamic parameters on tilting can predict for A-LOC.
  
  
  RESULTS
  Patients were recruited in a dedicated syncope unit and underwent neurocardiovascular evaluation as indicated under European Society of Cardiology guidelines to illicit a diagnosis of VVS. A set protocol of questioning occurred following induced syncope to determine the presence of A-LOC. The prevalence of A-LOC following syncope on tilting was 28% (44/159). Forty-two per cent of those≥60 years of age vs. 20%<60 years of age experienced amnesia post-induced syncope (P=0.003). However, regression analysis did not show age to be an independent predictor for A-LOC. Blood pressure change between those without amnesia and those with amnesia showed no significant difference (P=0.687). There was a significant difference in heart rate response; those experiencing amnesia had reduced bradycardic response on HUT compared with those without amnesia (P=0.001).
  
  
  CONCLUSIONS
  Amnesia for loss of consciousness is common in VVS. Although more prevalent, it is not unique to older age-groups. Absence of syncope associated bradycardia during HUT testing predicts for A-LOC.
authors: Falls and Blackout Unit, Department of Medical Gerontology, St James's Hospital, James' St, Dublin 8, Ireland. odwyercl@tcd.ie
authors: Clodagh
authors: C
authors: O'Dwyer
authors: Kathleen
authors: K
authors: Bennett
authors: Yvonne
authors: Y
authors: Langan
authors: Chie Wei
authors: CW
authors: Fan
authors: Rose Anne
authors: RA
authors: Kenny
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000647:Amnesia / Q000453:epidemiology* / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D015995:Prevalence; D011446:Prospective Studies; D012044:Regression Analysis; D012189:Retrospective Studies; D019462:Syncope, Vasovagal / Q000150:complications* / Q000503:physiopathology*; D014474:Unconsciousness / Q000209:etiology* / Q000503:physiopathology; D055815:Young Adult