OBJECTIVE: The goal was to determine if supranormal coronary blood flow increases myocardial oxygen consumption, high energy phosphate levels, and systolic function in the in situ autoperfused heart. METHODS: Thirteen anaesthetised open chest pigs with an intact, autoperfused coronary circulation, weight 30-40 kg, were studied. Measurements were made under basal conditions and during regional hyperperfusion of the anterior left ventricle produced by intracoronary infusion of adenosine (mean dose 3.3 mumol.min-1). Doppler coronary blood flow velocity in the anterior descending coronary artery, arterial and anterior interventricular venous blood oxygen content, high energy phosphates (by transmurally localised 31P NMR), and myocardial wall thickening (by sonomicrometry) were measured. RESULTS: With adenosine, coronary flow was increased to 355(SEM 59)% of control. Supranormal coronary flow produced no significant changes in anterior left ventricular oxygen consumption [99(12)% of control]. 31P NMR spectroscopy revealed no significant changes in the peak intensities of phosphocreatine or ATP in either the subendocardium or subepicardium (90-97% of control). Systolic anterior left ventricular wall thickening also did not change [107(13)% of control]. CONCLUSIONS: Supranormal coronary flow does not augment myocardial oxygen consumption, high energy phosphates, or systolic function in the in situ autoperfused heart. Myocardial oxygen delivery does not limit oxidative metabolism under normal conditions.
OBJECTIVE: The goal was to determine if supranormal coronary blood flow increases myocardial oxygen consumption, high energy phosphate levels, and systolic function in the in situ autoperfused heart. METHODS: Thirteen anaesthetised open chest pigs with an intact, autoperfused coronary circulation, weight 30-40 kg, were studied. Measurements were made under basal conditions and during regional hyperperfusion of the anterior left ventricle produced by intracoronary infusion of adenosine (mean dose 3.3 mumol.min-1). Doppler coronary blood flow velocity in the anterior descending coronary artery, arterial and anterior interventricular venous bloodoxygen content, high energy phosphates (by transmurally localised 31P NMR), and myocardial wall thickening (by sonomicrometry) were measured. RESULTS: With adenosine, coronary flow was increased to 355(SEM 59)% of control. Supranormal coronary flow produced no significant changes in anterior left ventricular oxygen consumption [99(12)% of control]. 31P NMR spectroscopy revealed no significant changes in the peak intensities of phosphocreatine or ATP in either the subendocardium or subepicardium (90-97% of control). Systolic anterior left ventricular wall thickening also did not change [107(13)% of control]. CONCLUSIONS: Supranormal coronary flow does not augment myocardial oxygen consumption, high energy phosphates, or systolic function in the in situ autoperfused heart. Myocardial oxygen delivery does not limit oxidative metabolism under normal conditions.
Authors: Ya Xu; Li Lu; Clifford Greyson; Mona Rizeq; Karin Nunley; Beata Wyatt; Michael R Bristow; Carlin S Long; Gregory G Schwartz Journal: Am J Physiol Heart Circ Physiol Date: 2005-12-09 Impact factor: 4.733
Authors: Ya Xu; Michael Gen; Li Lu; Jennifer Fox; Sara O Weiss; R Dale Brown; Daniel Perlov; Hasan Ahmad; Peili Zhu; Clifford Greyson; Carlin S Long; Gregory G Schwartz Journal: Am J Physiol Heart Circ Physiol Date: 2004-11-04 Impact factor: 4.733