title: Stability of pacing threshold, impedance, and R wave amplitude at rest and during exercise.
abstract: The pacing threshold of the human heart may be altered by physiological factors such as physical exercise. These changes may influence the individual programming of a pacemaker, since pacemakers can be programmed at pulse amplitudes of 2.5 volts and less. We investigated 22 patients with a multiprogrammable ventricular demand pacemaker 3 months after implantation; 16 patients had received a steroid-eluting lead and six patients had an Elgiloy lead. Parameters measured at rest and immediately after exercise were: Voltage threshold at pulse durations between 0.05 and 0.6 ms, impedance, R wave amplitude and energy consumption for the pacing threshold at 0.5 ms pulse duration. All patients performed a symptom limited supine bicycle exercise test. None of the investigated parameters showed a significant difference between rest and exercise, neither for the steroid eluting lead nor for the Elgiloy lead. The data suggest that the individual programming of a pacemaker adapted to the measurements at rest is also reliable and safe during exercise.
authors.affiliation: Department of Cardiology, University Hospital Eppendorf, Hamburg, Federal Republic of Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schuchert
authors.forename: K H
authors.initials: KH
authors.lastname: Kuck
authors.forename: W
authors.initials: W
authors.lastname: Bleifeld
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D011674:Pulse; D012146:Rest