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Zatebradine, a specific bradycardic agent, alters the hemodynamic and left ventricular mechanical actions of levosimendan, a new myofilament calcium sensitizer, in conscious dogs. J Pharmacol Exp Ther 1995 Oct;275(1):127-35

Date

10/01/1995

Pubmed ID

7562540

Abstract

The cardiovascular and left ventricular (LV) functional effects of levosimendan were examined (LSM; 0.5, 1.0, 2.0 and 4.0 micrograms.kg-1.min-1) in conscious, chronically instrumented dogs (n = 8) in the presence and absence of heart rate control with zatebradine (ZAT) or ZAT alone (0.25, 0.5 and 1.0 mg.kg-1). LSM increased heart rate (HR) cardiac output (CO), diastolic coronary blood flow velocity (DCBFV) and pressure-work index (PWI; calculated myocardial oxygen consumption) and decreased mean arterial, LV systolic and end-diastolic pressures, systemic vascular resistance and diastolic coronary vascular resistance (DCVR). ZAT alone decreased HR and PWI and increased stroke volume. LSM-induced increases in HR and PWI were attenuated by ZAT. Increases in DCBFV and decreases in DCVR occurred without changes in PWI in the presence of ZAT. LSM increased preload recruitable stroke work slope (Mw, 68 +/- 6 to 159 +/- 13 mm Hg) and +dP/dt. These positive inotropic effects were partially attenuated by ZAT. LSM alone decreased the time constant of isovolumic relaxation (tau, 36 +/- 2 to 29 +/- 2 ms). LSM-induced decreases in tau were blunted by ZAT, indicating that changes in tau were partially dependent on heart rate. LSM increased the maximal rate of segment lengthening to a similar degree in ZAT-treated versus -untreated dogs. ZAT alone had minimal effects on LV function. Control of LSM-induced tachycardia with ZAT decreases myocardial oxygen consumption but also partially attenuates the positive inotropic and lusitropic effects of LSM.

Author List

Pagel PS, Harkin CP, Hettrick DA, Warltier DC

Author

Paul S. Pagel MD, PhD Professor in the Anesthesiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Actin Cytoskeleton
Animals
Benzazepines
Calcium
Cardiotonic Agents
Consciousness
Coronary Circulation
Diastole
Dogs
Dose-Response Relationship, Drug
Drug Interactions
Female
Heart
Heart Rate
Hemodynamics
Hydrazones
Male
Myocardial Contraction
Pyridazines
Ventricular Function, Left
jenkins-FCD Prod-387 b0ced2662056320369de4e5cd5f21c218c03feb3