Performance of a specific algorithm to minimize right ventricular pacing: A multicenter study

Marc Strik*, Pascal Defaye, Romain Eschalier, Pierre Mondoly, Antonio Frontera, Philippe Ritter, Michel Haissaguerre, Sylvain Ploux, Kenneth A. Ellenbogen, Pierre Bordachar

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Web of Science)


BACKGROUND In Boston Scientific dual-chamber devices, the RYTHMIQ algorithm aims to minimize right ventricular pacing. OBJECTIVE 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. METHODS 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. RESULTS 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, 70/0; 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. CONCLUSION 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.
Original languageEnglish
Pages (from-to)1266-1273
JournalHeart Rhythm
Issue number6
Publication statusPublished - Jun 2016


  • Pacemaker
  • Dual
  • chamber
  • Right ventricle
  • Ventricular pacing
  • Dyssynchronopathy
  • AV block
  • AV conduction
  • Pacemaker algorithm
  • Boston Scientific

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