title: Novel experimental results in human cardiac electrophysiology: measurement of the Purkinje fibre action potential from the undiseased human heart.
abstract: Data obtained from canine cardiac electrophysiology studies are often extrapolated to the human heart. However, it has been previously demonstrated that because of the lower density of its K(+) currents, the human ventricular action potential has a less extensive repolarization reserve. Since the relevance of canine data to the human heart has not yet been fully clarified, the aim of the present study was to determine for the first time the action potentials of undiseased human Purkinje fibres (PFs) and to compare them directly with those of dog PFs. All measurements were performed at 37 °C using the conventional microelectrode technique. At a stimulation rate of 1 Hz, the plateau potential of human PFs is more positive (8.0 ± 1.8 vs 8.6 ± 3.4 mV, n = 7), while the amplitude of the spike is less pronounced. The maximal rate of depolarization is significantly lower in human PKs than in canine PFs (406.7 ± 62 vs 643 ± 36 V/s, respectively, n = 7). We assume that the appreciable difference in the protein expression profiles of the 2 species may underlie these important disparities. Therefore, caution is advised when canine PF data are extrapolated to humans, and further experiments are required to investigate the characteristics of human PF repolarization and its possible role in arrhythmogenesis.
authors: a MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.
authors: Norbert
authors: N
authors: Nagy
authors: b Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
authors: Tamás
authors: T
authors: Szél
authors: a MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.|b Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
authors: Norbert
authors: N
authors: Jost
authors: a MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.|b Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
authors: András
authors: A
authors: Tóth
authors: a MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.|b Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
authors: Julius
authors: J
authors: Gy Papp
authors: a MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary.|b Department of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary.
authors: András
authors: A
authors: Varró
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D004285:Dogs; D004594:Electrophysiology; D006801:Humans; D066298:In Vitro Techniques; D011690:Purkinje Fibers / Q000502:physiology*; D016276:Ventricular Function / Q000502:physiology*
keywords: Purkinje fibre; action potential; chien; coeur; dog; electrophysiology; fibre de Purkinje; heart; humain; human; potentiel d’action; ventricle; ventricule; électrophysiologie