Effect of arterial impedance changes on the end-systolic pressure-volume relation

W. L. Maughan, K. Sunagawa, D. Burkhoff, K. Sagawa

Research output: Contribution to journalArticlepeer-review

Abstract

To study the end-systolic pressure-volume relationship of left ventricle ejection against physiological afterload, we imposed seven simulated arterial impedances on excised canine left ventricles connected to a newly developed servo-pump system. We set each of the impedance parameters (resistance, capacitance, and characteristic impedance) to 50, 100, and 200% of normal value (resistance: 3 mm Hg sec/ml; capacitence: 0.4 ml/mm Hg; characteristic impedance: 0.2 mm Hg sec/ml), while leaving the other parameters normal. Under a given impedance, the end-systolic pressure-volume relationship was determined by preloading the ventricle at four different end-diastolic volumes. There was no significant changes in the slope of the end-systolic pressure-volume relationship with changes in any of the afterloading impedance parameters. However, the volume intercepts of the end-systolic pressure-volume relationship decreased significantly with resistance from 5.5 ± 1.0 (SE) ml at resistance equal to 1.5 mm Hg sec/ml to 0.6 ± 1.8 ml at resistance equal to 6 mm Hg sec/ml (P<0.01). The volume axis intercept also decreased with characteristic impedance, from 5.9 ± 2.0 ml at a characteristic impedance of 0.1 mm Hg sec/ml to 5.4 ± 2.1 ml at a characteristic impedance of 0.4 mm Hg sec/ml, (P<0.05). We conclude that the slope of the end-systolic pressure-volume relationship is insensitive to a wide range of changes in afterload impedance, but its volume intercepts is dependent on resistance and characteristic impedance.

Original languageEnglish (US)
Pages (from-to)595-602
Number of pages8
JournalCirculation research
Volume54
Issue number5
DOIs
StatePublished - 1984

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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