title: Simultaneous atrial and ventricular anti-tachycardia pacing as a novel method of rhythm discrimination.
abstract: OBJECTIVE
  To evaluate a new discrimination algorithm for supraventricular (SVT) and ventricular (VT) tachycardias, based on the response to simultaneous (A+V) atrial (A) and ventricular (V) anti-tachycardia pacing (ATP).
  
  
  METHODS
  Patients undergoing electrophysiological testing or dual-chamber implantable cardioverter-defibrillator (ICD) implantation were enrolled (N = 32) and underwent A+V ATP through a Marquis ICD with investigational software. If persisting after ATP, the rhythm was classified as VT if the first electrical event was sensed on the V channel and as an SVT otherwise.
  
  
  RESULTS
  Arrhythmia sequences (N = 275; 53 VT; 222 SVT) were analyzed in 26 patients (age = 51 +/- 17 years, 13 men, LVEF = 0.49 +/- 0.14). In response to A+V ATP, 55% of SVT versus 41% of VT episodes were terminated (P = NS). Termination of VT but not of SVT was more likely with faster (50% at ATP/arrhythmia cycle length (CL) = 0.81 vs 8% at ATP/arrhythmia CL = 0.88, P = 0.02) but not with longer ATP bursts (P = NS). Of the 115 arrhythmias that persisted after A+V ATP, the algorithm correctly classified 24 of 24 VT (GEE-adjusted sensitivity = 100%) and 85 of 91 SVT (GEE-adjusted specificity = 93%). Proarrhythmia was noted after two A+V ATP, in the form of atrial fibrillation induction and VT acceleration.
  
  
  CONCLUSIONS
  We describe a new algorithm that can discriminate between SVT and VT with a high sensitivity and specificity. This form of ATP can terminate 55% of SVT sequences. The performance of this new algorithm merits further testing in a large population of dual-chamber ICD patients.
authors.affiliation: University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA. sabas@upmc.edu
authors.forename: Samir
authors.initials: S
authors.lastname: Saba
authors.forename: Linda
authors.initials: L
authors.lastname: Baker
authors.forename: Leonard
authors.initials: L
authors.lastname: Ganz
authors.forename: William
authors.initials: W
authors.lastname: Barrington
authors.forename: Sandeep
authors.initials: S
authors.lastname: Jain
authors.forename: Ogundu
authors.initials: O
authors.lastname: Ngwu
authors.forename: Jill
authors.initials: J
authors.lastname: Christensen
authors.forename: Mark
authors.initials: M
authors.lastname: Brown
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000379:methods*; D017147:Defibrillators, Implantable; D005260:Female; D006325:Heart Atria; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D013617:Tachycardia, Supraventricular / Q000628:therapy*; D017180:Tachycardia, Ventricular / Q000628:therapy*; D013997:Time Factors