title: [Hemodynamic mechanisms of the left atrial pressure changes after pressor and depressor vasoactive drug injection].
abstract: In acute experiments in anesthetized cats the changes of the left atrial pressure, left ventricular myocardial contractility, its relaxation, venous return and cardiac output were studied after catecholamines or acetylcholine and histamine intravenous injection. When arterial pressure was elevated and venous return with cardiac output increased to the same level, the left atrial pressure decreased if the left ventricular myocardial contractility and its relaxation rate were increased equally. However, the left atrial pressure elevated, if left ventricular myocardial relaxation increased less than myocardial contractility. When arterial pressure was depressed, the left atrial pressure decreased if left ventricular myocardial contractility decreased less than myocardial relaxation diminished. If left ventricular myocardial contractility decreased significantly, the left atrial pressure increased. In the last case the value of cardiac output was more, than venous return one. The data suggest that after injection of the pressor and depressor vasoactive drugs, if the shifts of the venous return and cardiac output are equal, the changes of the nature and value of the left atrial pressure are dependent on the relation of the left ventricular myocardial contractility and its relaxation rate.
authors.forename: V I
authors.initials: VI
authors.lastname: Evlakhov
authors.forename: I Z
authors.initials: IZ
authors.lastname: Poiasov
mesh_terms: D000109:Acetylcholine / Q000008:administration & dosage; D000818:Animals; D016279:Atrial Function, Left / Q000187:drug effects* / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects / Q000502:physiology; D002415:Cats; D004837:Epinephrine / Q000008:administration & dosage; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D006632:Histamine / Q000008:administration & dosage; D007275:Injections, Intravenous; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D009638:Norepinephrine / Q000008:administration & dosage; D014662:Vasoconstrictor Agents / Q000008:administration & dosage*; D014665:Vasodilator Agents / Q000008:administration & dosage*; D012122:Ventilators, Mechanical
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D006632:Histamine; D000109:Acetylcholine; D009638:Norepinephrine; D004837:Epinephrine