title: Closed-loop cardiac pacing vs. conventional dual-chamber pacing with specialized sensing and pacing algorithms for syncope prevention in patients with refractory vasovagal syncope: results of a long-term follow-up.
abstract: OBJECTIVE
  Closed-loop stimulation (CLS) pacing has shown greater efficacy in preventing the recurrence of vasovagal syncope (VVS) in patients with a cardioinhibitory response to head-up tilt test (HUTT) compared with conventional pacing. Moreover, there is no conclusive evidence to support the superiority of CLS over the conventional algorithms for syncope prevention. This study retrospectively evaluated the effectiveness of CLS pacing compared with dual-chamber pacing with conventional specialized sensing and pacing algorithms for syncope prevention in the prevention of syncope recurrence in patients with refractory VVS and a cardioinhibitory response to HUTT during a long-term follow-up.
  
  
  RESULTS
  Forty-one patients (44% male, 53 ± 16 years) with recurrent, refractory VVS (26% with trauma) and a cardioinhibitory response to HUTT who had undergone pacemaker implantation were included in the analysis. Twenty-five patients received a dual-chamber CLS pacemaker (CLS group) and 16 patients received a dual-chamber pacemaker with conventional algorithms for syncope prevention (conventional pacing group): 9 patients with Medtronic rate drop response algorithm and 7 patients with Guidant-Boston Scientific sudden brady response algorithm. During the follow-up (mean 4.4 ± 3.0 years, interquartile range 2.2-7.4 years) one patient (4%) in the CLS group and six (38%) in the conventional pacing group had syncope recurrences (P= 0.016). The Kaplan-Meier actuarial estimate of first recurrence of syncope after 8 years was 4% in the CLS group and 40% in the conventional pacing group (P= 0.010).
  
  
  CONCLUSIONS
  The results of this retrospective analysis show that, in order to prevent a recurrence of VVS in patients with a cardioinhibitory response to HUTT, dual-chamber CLS pacing was more effective than dual-chamber pacing with conventional algorithms for syncope prevention in preventing bradycardia-related syncope.
authors.affiliation: Department of Emergency and Organ Transplantation, Cardiology Unit, University of Bari, Pietro Palmisano, Piazza Giulio Cesare 11, 70124 Bari, Italy. dr.palmisano@libero.it
authors.forename: Pietro
authors.initials: P
authors.lastname: Palmisano
authors.forename: Maria
authors.initials: M
authors.lastname: Zaccaria
authors.forename: Giovanni
authors.initials: G
authors.lastname: Luzzi
authors.forename: Frida
authors.initials: F
authors.lastname: Nacci
authors.forename: Matteo
authors.initials: M
authors.lastname: Anaclerio
authors.forename: Stefano
authors.initials: S
authors.lastname: Favale
mesh_terms: D000465:Algorithms; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005246:Feedback; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D019462:Syncope, Vasovagal / Q000175:diagnosis* / Q000517:prevention & control*; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome