Ventricular contractility in atrial fibrillation is predictable by mechanical restitution and potentiation

Shunsuke Suzuki, Junichi Araki, Terumasa Morita, Satoshi Mohri, Takeshi Mikane, Hiroki Yamaguchi, Shunji Sano, Tohru Ohe, Masahisa Hirakawa, Hiroyuki Suga

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


We recently found that contractility (E(max)) of an individual irregularly arrhythmic beat in electrically induced atrial fibrillation (AF) is reasonably predictable from the ratio of the preceding beat interval (RR1) to the beat interval immediately preceding RR1 (RR2) in the canine left ventricle. Moreover, the monotonically increasing relation between E(max) and the RR1-to-RR2 ratio (RR1/RR2) passed through or by the mean arrhythmic beat E(max) as well as the regular beat E(max) at RR1/RR2 = 1. We hypothesized that this E(max)-RR1/RR2 relation during irregular arrhythmia could be attributed to the basic characteristics of the mechanical restitution and potentiation. To test this, we adopted a known comprehensive equation describing the force restitution and potentiation as a function of two preceding beat intervals and simulated contractilities of irregular arrhythmic beats with randomized beat intervals on a computer. The simulated E(max)-RR1/RR2 relation reasonably resembled the one that we recently observed experimentally, supporting our hypothesis. We therefore conclude that the primary mechanism underlying the varying contractilities of irregular beats in AF is mechanical restitution and potentiation.

Original languageEnglish
Pages (from-to)H1513-H1519
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number5 44-5
Publication statusPublished - Nov 1998
Externally publishedYes


  • Arrhythmia
  • Calcium
  • Contractility
  • Interval-force relation
  • Irregular rhythm

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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