Rhythmo-inotropic dependence in isolated fragments of myocardium of patients with ischemic heart disease during pharmacological intervention on homeostasis of intracellular calcium

Aim. To study effect of a novel cardiotonic agent levosimendan on parameter s of inotropic response of isolated myocardial fragments taken from patient s with ischemic heart disease. Method. Inotropic responses of myocardial fr agments were registered in isometric regime at pacing frequency 0,5 Hz. Res ults. Levosimendan (0,03 mu M/l) potentiated inotropic effect of increased pacing rate without change of the contraction-relaxation cycle. This was as sociated with augmentation of amplitude (by 30%) and velocity of developmen t of inotropic response (by 48%). The dose of 0,73 mu M/l induced pronounce d cardiotonic effect (amplitude of a single contraction increased by more t han 50%) but failed to potentiate inotropic effects of other cardiotonic in terventions. Conclusion. Low doses of levosimendan preserve functional rese rve of the cardiac muscle and should be preferred when chronic derangements of coronary perfusion are present.