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Heart and Vessels

, Volume 14, Issue 2, pp 82–89 | Cite as

Myocardial mechanical restitution and potentiation partly underlie alternans decay of postextrasystolic potentiation: Simulation

  • Satoshi Mohri
  • Junichi Araki
  • Takeshi Imaoka
  • Gentaro Iribe
  • Masaki Maesako
  • Juichiro Shimizu
  • Hiromi Matsubara
  • Tohru Ohe
  • Masahisa Hirakawa
  • Hiroyuki Suga
Originals

Summary

We have reported that the postextrasystolic potentiation (PESP) decays in alternans or monotonically, respectively, depending on whether the first postextrasystolic beat interval has a compensatory pause or not, in the canine left ventricle. To get better mechanistic insight into the alternans PESP decay, we hypothesized that the myocardial mechanical restitution and potentiation could partly account for both types of PESP decay. To test this hypothesis, we simulated PESP decay on a computer using a documented equation combining myocardial mechanical restitution and potentiation. We changed the first postextrasystolic beat interval after a fixed extrasystolic beat interval without changing regular and other postextrasystolic beat intervals. The simulated PESP decayed in alternans or monotonically as a function only of the first postextrasystolic beat interval. Thus, the myocardial mechanical restitution and potentiation could partly account for both alternans and monotonic decay of PESP. We conclude that myocardial mechanical restitution and potentiation may partly underlie the initial two alternating beats, the first beat being the most potentiated and the second beat being the most depressed, of alternans PESP decay in the canine heart.

Key words

Force—interval relation Sarcoplasmic reticulum Calcium Extrasystole Compensatory pause 

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Copyright information

© Springer-Verlag 1999

Authors and Affiliations

  • Satoshi Mohri
    • 1
    • 2
  • Junichi Araki
    • 1
  • Takeshi Imaoka
    • 1
    • 2
  • Gentaro Iribe
    • 1
  • Masaki Maesako
    • 1
    • 3
  • Juichiro Shimizu
    • 1
  • Hiromi Matsubara
    • 2
  • Tohru Ohe
    • 2
  • Masahisa Hirakawa
    • 3
  • Hiroyuki Suga
    • 1
  1. 1.Department of Physiology IIOkayama University Medical SchoolShikata-cho, OkayamaJapan
  2. 2.Department of Cardiovascular MedicineOkayama University Medical SchoolOkayamaJapan
  3. 3.Department of Anesthesiology and ResuscitologyOkayama University Medical SchoolOkayamaJapan

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