Severe diastolic dysfunction with preserved energy conversion efficiency after countershock

Satoshi Yasuda, Toshiaki Shishido, Yoichi Goto

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

The left ventricular (LV) mechanical performance and the LV myocardial oxygen consumption (V̇O2)-to-pressure-volume area (PVA; LV total mechanical energy index) relationship were measured in isovolumic contraction of isolated blood-perfused dog hearts before and after direct current (DC) countershocks. At a constant LV volume, DC shocks increased LV end-diastolic pressure progressively and strikingly with the progression of myocardial edema and a marked prolongation of the time constant of LV pressure decay. In contrast, DC shocks changed neither the slope of the LV end-systolic pressure-volume relationship nor the contractile efficiency (the slope of the V̇O2-PVA relationship). The oxygen cost of contractility (the slope of the relationship between PVA-independent V̇O2 and LV contractility) increased 27% after DC shocks. However, the magnitude of this change was considerably smaller than that previously reported in postischemic stunned myocardium (123%), suggesting that the adverse effect of DC shocks on the energy cost of excitation-contraction coupling is relatively minor. Thus, despite the severe diastolic dysfunction, DC shocks do not substantially impair either the efficiency of cross-bridge cycling or calcium cycling. Myocardial interstitial edema is more likely a potential mechanism of diastolic dysfunction after DC shocks.

Original languageEnglish
Pages (from-to)H583-H592
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume273
Issue number2 42-2
DOIs
Publication statusPublished - 1997
Externally publishedYes

Keywords

  • Diastolic function
  • Electric countershock
  • Excitation-contraction coupling
  • Myocardial oxygen consumption
  • Pressure-volume relationship

ASJC Scopus subject areas

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

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