title: The reverse mode switch algorithm: how well does it work?
abstract: BACKGROUND
  The performance of the Reverse Mode Switch (RMS) algorithm, aimed at minimizing right ventricular pacing by operating in the AAI(R) mode with switch to the DDD(R) mode if atrioventricular (AV) conduction loss is detected, is not well known.
  
  
  OBJECTIVE
  To determine the appropriateness of the RMS episodes available from patient follow-up data at our center.
  
  
  METHODS
  Patients with the TELIGEN dual-chamber implantable cardioverter-defibrillator and the RMS algorithm activated were identified. The RMS episodes with available electrograms were analyzed and classified as appropriate (AV conduction loss) or inappropriate (non-AV conduction loss) events. Cumulative percentage of ventricular pacing and amount of premature ventricular complexes (PVCs) were recorded.
  
  
  RESULTS
  Of 21 patients, RMS episodes had occurred in 19 of them, with a mean of 527 episodes per month. Of the 172 RMS episodes available for analysis, 27 (16%) were classified as appropriate and 145 (84%) as inappropriate. Almost all (91%) inappropriate RMS episodes were due to PVC, and there was a positive correlation between the number of total RMS episodes per month and the number of PVCs per month (P < .0005). Considering patients with only inappropriate RMS episodes (n = 11), there was a positive correlation between the percentage of ventricular pacing and the number of RMS episodes per month (P < .05).
  
  
  CONCLUSIONS
  A large majority of the RMS episodes available for analysis inappropriately triggered switch from the AAI(R) mode to the DDD(R) mode owing to PVCs. Patients with the RMS algorithm and elevated PVC burden are probably at risk of a high percentage of unnecessary right ventricular pacing.
authors.affiliation: Cardiac Arrhythmia and Electrophysiology Unit, Department of Cardiology, Hospital Virgen de Salud, Toledo, Spain.
authors.forename: Finn
authors.initials: F
authors.lastname: Akerström
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Arias
authors.forename: Marta
authors.initials: M
authors.lastname: Pachón
authors.forename: Alberto
authors.initials: A
authors.lastname: Puchol
authors.forename: Jesús
authors.initials: J
authors.lastname: Jiménez-López
authors.forename: Luis
authors.initials: L
authors.lastname: Rodríguez-Padial
mesh_terms: D000368:Aged; D000465:Algorithms; D001283:Atrioventricular Node / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006352:Heart Ventricles / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
keywords: %AP; %VP; AV; AV conduction; CRT; EGM; ICD; Implantable cardioverter-defibrillator; LRL; LVEF; MVP; PVC; Pacing mode; Premature ventricular complex; RMS; RV; Reverse Mode Switch; Right ventricular pacing; atrioventricular; cardiac resynchronization therapy; electrogram; implantable cardioverter-defibrillator; left ventricular ejection fraction; lower rate limit; managed ventricular pacing; percentage of atrial pacing; percentage of ventricular pacing; premature ventricular complex; right ventricular