title: O2 consumption of dog heart under decreased coronary perfusion and propranolol.
abstract: We compared the effects of decreased coronary perfusion pressure (CP) and propranolol on the relation between left ventricular O2 consumption (VO2) and systolic pressure-volume area (PVA). PVA represents total mechanical energy generated by contraction and is the area under the end-systolic pressure-volume (PV) line and systolic PV trajectory. In excised cross-circulated dog hearts, a decrease in CP from 82 (mean) to 51 mmHg decreased ventricular contractility index Emax (slope of end-systolic PV relation) by 17% (P less than 0.05) and slightly (P less than 0.05 in 3 of 11 hearts) lowered the VO2-PVA relation in a parallel fashion. A further decrease in CP to 32 mmHg decreased Emax by 56% (P less than 0.05) and considerably (P less than 0.05) lowered the VO2-PVA relation by decreasing both the VO2-axis intercept by 26% (P less than 0.05) and the slope by 24% (P less than 0.05) from control. Propranolol decreased Emax by 48% (P less than 0.05) and the VO2-axis intercept by 25% (P less than 0.05) without changing the slope (P greater than 0.05). We attributed the different response of the VO2-PVA relation to the difference of the coronary O2 supply-demand balance between decreased CP and propranolol.
authors.affiliation: Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Suga
authors.forename: Y
authors.initials: Y
authors.lastname: Goto
authors.forename: Y
authors.initials: Y
authors.lastname: Yasumura
authors.forename: T
authors.initials: T
authors.lastname: Nozawa
authors.forename: S
authors.initials: S
authors.lastname: Futaki
authors.forename: N
authors.initials: N
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Uenishi
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D004285:Dogs; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010477:Perfusion; D011433:Propranolol / Q000494:pharmacology*
chemical_list: D011433:Propranolol