title: Metabolic response of the human heart to inotropic stimulation: in vivo phosphorus-31 studies of normal and cardiomyopathic myocardium.
abstract: In order to determine if an increase in myocardial oxygen consumption is accompanied by changes in high energy phosphates in normal subjects and patients with dilated cardiomyopathy, phosphorus-31 spectra were acquired under resting conditions and during dobutamine infusion. In seven normal subjects, dobutamine raised the rate-pressure product to 226% of control. The ratio of PCr/ATP was 1.86 +/- 0.17 (mean +/- SE) under resting conditions and 1.90 +/- 0.22 (P = 0.44) with dobutamine infusion. In eight patients with dilated cardiomyopathy, dobutamine raised the rate-pressure product to 161% of control. As in the normal subjects, the ratio of PCr/ATP under resting conditions (1.63 +/- 0.24) was unchanged during dobutamine infusion (1.57 +/- 0.24, P = 0.38). These data indicate that increases in cardiac work do not have a major effect on high energy phosphate concentrations in normal subjects or in patients with clinically compensated dilated cardiomyopathy.
authors.affiliation: Magnetic Resonance Unit VA Medical Center, San Francisco, California.
authors.forename: S
authors.initials: S
authors.lastname: Schaefer
authors.forename: G G
authors.initials: GG
authors.lastname: Schwartz
authors.forename: S K
authors.initials: SK
authors.lastname: Steinman
authors.forename: D J
authors.initials: DJ
authors.lastname: Meyerhoff
authors.forename: B M
authors.initials: BM
authors.lastname: Massie
authors.forename: M W
authors.initials: MW
authors.lastname: Weiner
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000378:metabolism*; D004280:Dobutamine / Q000494:pharmacology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D013268:Stimulation, Chemical
chemical_list: D010725:Phosphocreatine; D004280:Dobutamine; D000255:Adenosine Triphosphate