title: A study comparing VVI and DDI pacing in elderly patients with carotid sinus syndrome.
abstract: OBJECTIVE
  To determine whether single chamber ventricular demand (VVI) pacing is adequate for elderly patients with carotid sinus syndrome.
  
  
  METHODS
  Prospective double blind randomised cross over study.
  
  
  METHODS
  Tertiary referral centre.
  
  
  METHODS
  30 consecutive patients aged over 60 years with carotid sinus syndrome referred for cardiac pacing.
  
  
  METHODS
  Patients underwent dual chamber pacemaker implantation and were then randomised to two three-month periods of VVI and DDI pacing.
  
  
  METHODS
  Responses to cardiovascular tests (vasodepression during carotid sinus massage, pacemaker effect, postural blood pressure measurements, and response to head up tilt), and symptoms.
  
  
  RESULTS
  11 patients developed profound hypotension during upright carotid sinus massage while pacing VVI compared with only two while pacing DDI. The upright pacemaker effect was greater in VVI (VVI, -31 (SD 19) mm Hg v DDI, -4 (12) mm Hg; P < 0.001). Postural blood pressure measurements and responses to head up tilt did not vary. Eleven patients were unable to tolerate VVI pacing and had to be withdrawn early from this limb of the study (group A). Fourteen of the remainder completed diary cards and did not express a preference (group B). No patient preferred VVI. Group A patients were older (group A, 78 (6) years v group B, 70 (9) years; P < 0.05), were more likely to be female (group A, 73% v group B, 14%; P < 0.01), and were more likely to have orthostatic hypotension while pacing DDI (group A, 46% v group B, 0%; P < 0.01). Group A and B patients could not be differentiated by other prepacing clinical or haemodynamic variables.
  
  
  CONCLUSIONS
  Elderly patients with carotid sinus syndrome are likely to develop symptomatic hypotension following VVI pacing. The optimum pacing mode for individual patients cannot be predicted by simple cardiovascular tests before pacing.
authors.affiliation: Cardiovascular Investigation Unit, Royal Victoria Infirmary, Newcastle upon Type, United Kingdom.
authors.forename: S J
authors.initials: SJ
authors.lastname: McIntosh
authors.forename: J
authors.initials: J
authors.lastname: Lawson
authors.forename: R S
authors.initials: RS
authors.lastname: Bexton
authors.forename: R G
authors.initials: RG
authors.lastname: Gold
authors.forename: M M
authors.initials: MM
authors.lastname: Tynan
authors.forename: R A
authors.initials: RA
authors.lastname: Kenny
mesh_terms: D000368:Aged; D017704:Baroreflex; D001794:Blood Pressure; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects / Q000379:methods*; D002346:Carotid Sinus; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D010991:Plethysmography; D011446:Prospective Studies; D013575:Syncope / Q000628:therapy*; D013577:Syndrome; D018667:Tilt-Table Test