title: Proarrhythmic effect of pacemaker stimulation in patients with implanted cardioverter-defibrillators.
abstract: BACKGROUND
  We sought to determine the potential of right ventricular VVI backup pacing to induce ventricular tachyarrhythmias in patients with implanted cardioverter-defibrillators.
  
  
  RESULTS
  All consecutive patients presenting exclusively with pacemaker-induced tachycardias (PITs) were included in a prospective study using a crossover protocol. Patients were randomized to either group 1 (augmentation of the baseline frequency of the pacemaker to 60 bpm) or group 2 (pacemaker turned off) and were followed up for 1 year and then crossed over to the other programming, looking for reoccurrence of PIT. Of 150 consecutive patients, 39 (26%) had PIT, 13 of them exclusively (8.6%). Forty of 1063 analyzed tachyarrhythmias of all the patients were PIT (3%). Before inclusion in the study, the patients had 2.7+/-0.9 PITs in 11+/-6.5 months with their pacemakers programmed empirically at 42.3 bpm. During the study phase, no PIT occurred while the pacemaker was turned off, whereas programming to 60 bpm led to the recurrence of PIT in 5 of 6 patients (1.4+/-0.6 per patient). At the end of the study, 9 patients underwent a prolonged follow-up with their pacemakers turned off, resulting in spontaneous episodes of ventricular tachycardia/fibrillation in 5 patients, but PITs were no longer observed.
  
  
  CONCLUSIONS
  This crossover protocol proves the potential proarrhythmic effect of pacemaker stimulation in implantable cardioverter-defibrillator patients. Resulting PITs led to clinical symptoms and antitachycardia therapy by the implantable cardioverter-defibrillator. Thus, in patients presenting with PIT but without a pacemaker indication, the pacemaker feature should be turned off, or, alternatively, the longest possible escape interval should be programmed.
authors.affiliation: II. Medical Clinic, University Hospital, Langenbeckstrasse 1, D-55131 Mainz, Germany. himmrich@2-med.klinik.uni-mainz.de
authors.forename: Ewald
authors.initials: E
authors.lastname: Himmrich
authors.forename: Oliver
authors.initials: O
authors.lastname: Przibille
authors.forename: Christian
authors.initials: C
authors.lastname: Zellerhoff
authors.forename: Andreas
authors.initials: A
authors.lastname: Liebrich
authors.forename: Stefan
authors.initials: S
authors.lastname: Rosocha
authors.forename: Klaus
authors.initials: K
authors.lastname: Andreas
authors.forename: Dirk
authors.initials: D
authors.lastname: Nebeling
authors.forename: Babatunde
authors.initials: B
authors.lastname: Omogbehin
authors.forename: Jürgen
authors.initials: J
authors.lastname: Meyer
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects* / Q000379:methods; D018592:Cross-Over Studies; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D011446:Prospective Studies; D055502:Secondary Prevention; D013318:Stroke Volume; D013610:Tachycardia / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome