Intrinsic Conduction Maximizes Cardiopulmonary Performance in Patients with Dual Chamber Pacemakers


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17 Scopus citations


Dual chamber pacemaker programmability allows the possibility of atriallytracked ventricular pacing in patients who would otherwise have intrinsic atrioventricular (AV) conduction. Thirteen patients with permanent AV sequential pacemakers (ages 50–79) were evaluated with paired exercise tests to determine the Cardiopulmonary effects of pacemaker induced right ventricular activation compared with normal AV and intraventricular conduction. Peak oxygen uptake (VO2), oxygen pulse (O2P), respiratory rate (RR), and respiratory exchange ratio (RER) were determined using breath by‐breath analysis of expired gases. Patients exercised to fatigue and exercise tests were performed in random sequence. For patients with intrinsic AV conduction (group I, n = 8) the AV delay was programmed to preserve intrinsic conduction during one study; the alternate test used AV delay programming to produce ventricular pacing. Five patients with chronic AV block (group II) acted as a control for the effects of a rate adaptive AV delay compared to a fixed AV delay. Paired t‐testing showed a significantly lower peak VO2 (P < 0.015) and O2P (P < 0.01) in patients with atrially‐tracked ventricular pacing compared to intrinsic conduction. In contrast, group II showed a significant improvement in peak VO2 with rate adaptive AV delay compared to fixed AV delay programming (P < 0.05). In conclusion, intrinsic conduction should be preserved in patients with dual chamber pacemakers whenever possible.

Original languageEnglish (US)
Pages (from-to)1787-1791
Number of pages5
JournalPacing and Clinical Electrophysiology
Issue number11
StatePublished - Nov 1991


  • atrioventricular delay
  • conduction
  • dual chamber pacemaker
  • exercise testing
  • oxygen consumption

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine


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