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Metabolic response of the human heart to inotropic stimulation: In vivo phosphorus‐31 studies of normal and cardiomyopathic myocardium
Author(s) -
Schaefer Saul,
Schwartz Gregory G.,
Steinman Sean K.,
Meyerhoff Dieter J.,
Massie Barry M.,
Weiner Michael W.
Publication year - 1992
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910250205
Subject(s) - dobutamine , medicine , high energy phosphate , cardiology , dilated cardiomyopathy , inotrope , cardiomyopathy , heart rate , rate pressure product , phosphocreatine , blood pressure , endocrinology , hemodynamics , heart failure , energy metabolism
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 cardio‐myopathy, phosphorus‐31 spectra were acquired under resting conditions and during do‐butamine 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. © 1992 Academic Press, Inc.