title: Single-beat estimation of the slope of the end-systolic pressure-volume relation in the human left ventricle.
abstract: This study assessed a new method of estimating the slope (Ees) of the end-systolic pressure-volume relation (ESPVR) from a single beat of the human heart. Left ventricular pressure was recorded with a high-fidelity micromanometer in patients with heart disease during left ventriculography. Peak isovolumic pressure at the end-disastolic volume was estimated by a curve-fitting technique from an isovolumic left ventricular pressure curve. The ESPVR line was drawn from the estimated peak isovolumic pressure-volume point tangential to the left upper corner of the pressure-volume loop. The slope of this estimated ESPVR line from single-beat analysis was compared with the slope of the ESPVR line obtained from three pressure-volume loops in 16 patients given angiotensin II or nitroglycerin infusion. The estimated Ees was 5.0 +/- 2.2 mm Hg/ml/m2, and the conventional Ees was 4.9 +/- 2.7 mm Hg/ml/m2. The estimated Ees showed a positive correlation with the conventional Ees (r = 0.91, p less than 0.001, SEE = 1.2 mm Hg/ml/m2). In the other 13 patients, after dobutamine infusion (5 micrograms/kg/min i.v.) the estimated Ees increased significantly from 5.6 +/- 1.4 to 7.4 +/- 2.0 mm Hg/ml/m2 (p less than 0.01). Thus, the estimated Ees approximated the conventional Ees and was sensitive to a positive inotropic intervention. We conclude that this single-beat analysis method facilitates assessment of the beat-by-beat ESPVR of the human heart.
authors.affiliation: First Department of Internal Medicine, Kobe University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
authors.forename: S
authors.initials: S
authors.lastname: Tomimoto
authors.forename: M
authors.initials: M
authors.lastname: Odake
authors.forename: T
authors.initials: T
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: K
authors.initials: K
authors.lastname: Hata
authors.forename: H
authors.initials: H
authors.lastname: Takaoka
authors.forename: H
authors.initials: H
authors.lastname: Fukuzaki
mesh_terms: D000804:Angiotensin II; D002932:Cineangiography / Q000379:methods; D004280:Dobutamine; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology*; D005996:Nitroglycerin; D013318:Stroke Volume / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*
chemical_list: D000804:Angiotensin II; D004280:Dobutamine; D005996:Nitroglycerin