title: The relationship between carotid sinus hypersensitivity, orthostatic hypotension, and vasovagal syncope: a case-control study.
abstract: OBJECTIVE
  Previous uncontrolled studies reported an overlap between carotid sinus hypersensitivity (CSH), vasovagal syncope (VVS), and orthostatic hypotension (OH). We conducted a case-control study evaluating this relationship in a large patient cohort.
  
  
  RESULTS
  The electronically stored continuous electrocardiograph and blood pressure (BP) measurements for active stand and head-up tilt-table (HUT) tests of 302 consecutive patients investigated with carotid sinus massage (CSM) were analysed. Carotid sinus hypersensitivity was defined as >or=3 s asystole and/or systolic BP (SBP) drop of >or=50 mmHg during CSM. Orthostatic hypotension was defined as BP reductions of >or=20 mmHg systolic or of >or=10 mmHg diastolic, whereas VVS was diagnosed with a positive HUT test. There was no significant difference in the number of subjects with OH (57 vs. 55%; P = 0.778) or HUT-positive VVS (45 vs. 47%; P = 0.828) between cases with CSH and controls without CSH. Carotid sinus hypersensitivity subjects had significantly larger SBP reduction (P = 0.039) and longer time to nadir (P = 0.007) during active stand, and trends to vasodepressor (P = 0.071) and dysautonomic responses to HUT (P = 0.151).
  
  
  CONCLUSIONS
  Carotid sinus hypersensitivity, OH, and VVS are common conditions affecting patients with syncope and falls which are likely to co-exist in such individuals. The differences in haemodynamic response patterns to active stand and HUT in CSH subjects could be the result of an age-associated delay in sympathetic responses.
authors.affiliation: Institute for Ageing and Health, Wolfson Centre, Campus for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Maw Pin
authors.initials: MP
authors.lastname: Tan
authors.forename: Julia L
authors.initials: JL
authors.lastname: Newton
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Chadwick
authors.forename: Steve W
authors.initials: SW
authors.lastname: Parry
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013575:Syncope / Q000175:diagnosis / Q000453:epidemiology*; D019462:Syncope, Vasovagal / Q000175:diagnosis / Q000453:epidemiology*; D018667:Tilt-Table Test / Q000706:statistics & numerical data; D006113:United Kingdom / Q000453:epidemiology