Atrial muscle isolated from guinea pigs subjected to Escherichia coli endotoxin shock was used to study the myocardial changes associated with this experimental disease state. Isometric contractile tension and its first derivative (dT/dt) consistently were depressed by about 45% in muscle from the shock group (P less than 0.001), but contraction time intervals of the shock tissues were not sign...

The positive inotropic action of blood plasma on isolated hearts has been known for a long time (Bowditch, 1871; Ringer, 1885; Clark, 1913; Hajdu, 1957; Hajdu, Leonard & Akers, 1957a; Hajdu, Weiss & Titus, 1957 b), and the observations recorded by various authors suggest that a number of different plasma components are responsible for positive inotropic activity. Hajdu et al. (1957b) isolated a...

Endothelin, a 21-amino acid vasoactive peptide, is among the most potent positively inotropic agents yet described in mammalian heart. Having demonstrated that endothelin's inotropic effect is due, in part, to an apparent sensitization of cardiac myofilaments to intracellular calcium, we determined whether this could be due to a rise in intracellular pH (pHi). In isolated adult rat ventricular ...

Glucagon increased heart rate and contractile force in the anesthetized dog and increased isometric tension in the isolated dog papillary muscle. The positive inotropic and chronotropic responses were not abolished or reduced by previous administration of the beta-receptor blocking agent propranolol, in doses of 0.5 mg/kg. Glucagon increased the force and rate of cardiac contraction even when c...

Introduction: During coronary artery bypass graft (CABG) surgery with cardiopulmonary bypass (CPB), the role of cardioplegic solution which results in cardiac arrest, is critical. This study was planned to evaluate the clinical impacts of N acetylcysteine (NAC) enriched cold-blood cardioplegia on early reperfusion injury in patients with ischaemic heart disease undergoing CABG Methods: In a...

The purpose of this study was to characterize by pharmacological means the inotropic action of prostaglandin D2 (PGD2) in the guinea-pig heart. In the whole heart perfused at constant pressure, PGD2 (0.01-10 micrograms) reduced coronary flow rate and decreased left ventricular contractile force in a dose-dependent manner. When the coronary vasoconstricting effect of PGD2 was antagonized by the ...

Mechanical function remains depressed for hours and days after even brief periods of ischemia. To determine whether the depressed function of the reperfused myocardium could be improved by inotropic stimulation, we studied segmental function during ischemia and after reperfusion using mercury-in-Silastic length gauges in 15 dogs. During coronary artery occlusion, segmental function could not be...

BACKGROUND Most volatile anesthetics exhibit a direct myocardial depressant effect. This side effect often limits their applicability in patients with impaired cardiac function. Xenon is a new gaseous anesthetic that did not show any adverse cardiovascular effects in clinical and experimental studies. The authors tested the hypothesis that xenon does not affect myocardial contractility or the p...

Adrenomedullin (ADM) is an endogenous peptide with favorable hemodynamic effects in vivo. In this study, we characterized the direct functional effects of ADM in isolated preparations from human atria and ventricles. In electrically stimulated human nonfailing right atrial trabeculae, ADM (0.0001-1 micromol/l) increased force of contraction in a concentration-dependent manner, with a maximal in...

Because of conflicting reports on the influence of extracellular potassium concentration ([K]o) on the inotropic action of cardiac glycosides, we compared the effects of varying [K]o (1.5, 4.5, and 7.5mM) on the inotropic action and myocardial concentration of tritiated digoxin (5 X 10~M) using the isolated cat papillary muscle. The time course of the inotropic response to digoxin was significa...