title: Benefit of pacemaker therapy in patients with presumed neurally mediated syncope and documented asystole is greater when tilt test is negative: an analysis from the third International Study on Syncope of Uncertain Etiology (ISSUE-3).
abstract: BACKGROUND
  In the Third International Study on Syncope of Uncertain Etiology (ISSUE-3), cardiac pacing was effective in reducing recurrence of syncope in patients with presumed neurally mediated syncope (NMS) and documented asystole but syncope still recurred in 25% of them at 2 years. We have investigated the role of tilt testing (TT) in predicting recurrences.
  
  
  RESULTS
  In 136 patients enrolled in the ISSUE-3, TT was positive in 76 and negative in 60. An asystolic response predicted a similar asystolic form during implantable loop recorder monitoring, with a positive predictive value of 86%. The corresponding values were 48% in patients with non-asystolic TT and 58% in patients with negative TT (P=0.001 versus asystolic TT). Fifty-two patients (26 TT+ and 26 TT-) with asystolic neurally mediated syncope received a pacemaker. Syncope recurred in 8 TT+ and in 1 TT- patients. At 21 months, the estimated product-limit syncope recurrence rates were 55% and 5%, respectively (P=0.004). The TT+ recurrence rate was similar to that seen in 45 untreated patients (control group), which was 64% (P=0.75). The recurrence rate was similar between 14 patients with asystolic and 12 with non-asystolic responses during TT (P=0.53).
  
  
  CONCLUSIONS
  Cardiac pacing was effective in neurally mediated syncope patients with documented asystolic episodes in whom TT was negative; conversely, there was insufficient evidence of efficacy from this data set in patients with a positive TT even when spontaneous asystole was documented. Present observations are unexpected and need to be confirmed by other studies. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT01463358.
authors: Department of Cardiology, Ospedali del Tigullio, Lavagna, Italy.
authors: Michele
authors: M
authors: Brignole
authors: Paolo
authors: P
authors: Donateo
authors: Marco
authors: M
authors: Tomaino
authors: Riccardo
authors: R
authors: Massa
authors: Matteo
authors: M
authors: Iori
authors: Xulio
authors: X
authors: Beiras
authors: Angel
authors: A
authors: Moya
authors: Teresa
authors: T
authors: Kus
authors: Jean Claude
authors: JC
authors: Deharo
authors: Silvia
authors: S
authors: Giuli
authors: Alessandra
authors: A
authors: Gentili
authors: Richard
authors: R
authors: Sutton
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D004311:Double-Blind Method; D005060:Europe; D005260:Female; D006323:Heart Arrest / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012008:Recurrence; D019462:Syncope, Vasovagal / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D018667:Tilt-Table Test; D013997:Time Factors; D016896:Treatment Outcome
keywords: arrhythmias, cardiac; autonomic effect; baroreflexes; biological pacemakers; cardiology; nervous system; syncope; tilt-table test