title: Influence of permanent right ventricular pacing on cardiorespiratory exercise parameters in chronic heart failure patients with implanted cardioverter defibrillators.
abstract: OBJECTIVE
  Patients with chronic heart failure and implanted cardioverter-defibrillators (ICDs) may have a higher incidence of new-onset or worsening heart failure requiring hospitalization with dual-chamber ICDs compared with single-chamber ICDs.
  
  
  METHODS
  The purpose of this study was to show the impact of permanent right ventricular (RV) pacing on exercise capacity and related cardiorespiratory parameters in patients with chronic heart failure and ICDs.
  
  
  METHODS
  Seventeen patients with chronic heart failure and a dual-chamber ICD performed cardiopulmonary exercise testing (CPX) on 3 different days. After CPX 1, patients were randomized either to back-up pacing or permanent RV pacing. After 3 months, CPX 2 was performed and patients changed groups (crossover design); CPX 3 was performed after 3 additional months.
  
  
  RESULTS
  Maximal values for workload (108 +/- 46 W vs 117 +/- 48 W, p < 0.01), oxygen uptake (Vo(2)) [21.0 +/- 5.3 mL/min/kg vs 22.5 +/- 6.4 mL/min/kg, p < 0.05], oxygen pulse (13 +/- 3.7 mL vs 14 +/- 4.0 mL, p < 0.05), and metabolic equivalent (6.0 +/- 1.5 vs 6.4 +/- 1.8, p < 0.05) were significantly lower with permanent RV pacing compared to back-up pacing. Workload, Vo(2), and oxygen pulse were significantly reduced at the ventilatory anaerobic threshold, while workload and Vo(2) were significantly lower at the respiratory compensation point. No differences were found for maximal heart rate, minute ventilation Ve, and respiratory exchange ratio. The Ve/carbon dioxide production slope was significantly steeper with permanent RV pacing compared to back-up pacing.
  
  
  CONCLUSIONS
  Permanent RV pacing significantly reduced maximal and submaximal measures of exercise. For patients with chronic heart failure and sufficient atrioventricular conduction, every effort should be made to minimize permanent right ventricular pacing.
authors.affiliation: Department of Medicine, Division of Cardiology, Medical University, Graz, Austria. manfred.wonisch@meduni-graz.at
authors.forename: Manfred
authors.initials: M
authors.lastname: Wonisch
authors.forename: Peter
authors.initials: P
authors.lastname: Lercher
authors.forename: Daniel
authors.initials: D
authors.lastname: Scherr
authors.forename: Robert
authors.initials: R
authors.lastname: Maier
authors.forename: Rochus
authors.initials: R
authors.lastname: Pokan
authors.forename: Peter
authors.initials: P
authors.lastname: Hofmann
authors.forename: Serge P
authors.initials: SP
authors.lastname: von Duvillard
mesh_terms: D015308:Anaerobic Threshold; D002908:Chronic Disease; D018592:Cross-Over Studies; D017147:Defibrillators, Implantable; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D010138:Pacemaker, Artificial / Q000009:adverse effects*; D011659:Pulmonary Gas Exchange; D012123:Pulmonary Ventilation