title: Performance of a specific algorithm to minimize right ventricular pacing: A multicenter study.
abstract: In Boston Scientific dual-chamber devices, the RYTHMIQ algorithm aims to minimize right ventricular pacing.
  
  
  
  We evaluated the performance of this algorithm determining (1) the appropriateness of the switch from the AAI(R) mode with backup VVI pacing to the DDD(R) mode in case of suspected loss of atrioventricular (AV) conduction and (2) the rate of recorded pacemaker-mediated tachycardia (PMT) when AV hysteresis searches for restored AV conduction.
  
  
  
  In this multicenter study, we included 157 patients with a Boston Scientific dual-chamber device (40 pacemakers and 117 implantable cardioverter-defibrillators) without permanent AV conduction disorder and with the RYTHMIQ algorithm activated. We reviewed the last 10 remote monitoring-transmitted RYTHMIQ and PMT episodes.
  
  
  
  We analyzed 1266 episodes of switch in 142 patients (90%): 207 (16%) were appropriate and corresponded to loss of AV conduction, and 1059 (84%) were inappropriate, of which 701 (66%) were related to compensatory pause (premature atrial contraction, 7%; premature ventricular contraction, 597 (56%); or both, 27 (3%)) or to a premature ventricular contraction falling in the post-atrial pacing ventricular refractory period interval (219, 21%) and 94 (10%) were related to pacemaker dysfunction. One hundred fifty-four PMT episodes were diagnosed in 27 patients (17%). In 85 (69%) of correctly diagnosed episodes, the onset of PMT was directly related to the algorithm-related prolongation of the AV delay, promoting AV dissociation and retrograde conduction.
  
  
  
  This study highlights some of the limitations of the RYTHMIQ algorithm: high rate of inappropriate switch and high rate of induction of PMT. This may have clinical implications in terms of selection of patients and may suggest required changes in the algorithm architecture.
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France; Maastricht University Medical Center, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands. Electronic address: m.strik@maastrichtuniversity.nl.
authors.forename: Marc
authors.initials: M
authors.lastname: Strik
authors.affiliation: Centre Hospitalier Universitaire de Grenoble, La Tronche, France.
authors.forename: Pascal
authors.initials: P
authors.lastname: Defaye
authors.affiliation: Clermont Université, Université d'Auvergne, Cardio Vascular Interventional Therapy and Imaging (CaVITI), Image Science for Interventional Techniques (ISIT), UMR6284, CHU Clermont-Ferrand, Cardiology Department, Clermont-Ferrand, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Eschalier
authors.affiliation: Centre Hospitalier Universitaire de Toulouse, Toulouse, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mondoly
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Frontera
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Ritter
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Haïssaguerre
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Ploux
authors.affiliation: VCU Health, Richmond, Virginia.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Ellenbogen
authors.affiliation: Haut-Lévêque Hospital, Centre Hospitalier Universitaire de Bordeaux; LIRYC institute, Pessac, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Bordachar
mesh_terms: D000368:Aged; D000465:Algorithms; D001283:Atrioventricular Node; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods; D017147:Defibrillators, Implantable / Q000592:standards; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004562:Electrocardiography / Q000379:methods; D004867:Equipment Design; D005260:Female; D006327:Heart Block / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D058996:Quality Improvement
keywords: AV block; AV conduction; Boston Scientific; Dual; Dyssynchronopathy; Pacemaker; Pacemaker algorithm; RYTHMIQ; Right ventricle; Ventricular pacing; chamber