All are true statement about digitalis action EXCEPT:
Ans. (b) Pumps sodium out of cell* Digitalis is one of the cardiac glycosides which increases myocardial contractility and output in a hypodynamic heart without a proportionate increase in oxygen consumption.* Compounds in cardiac glycosides group include: digoxin, digitoxin, strophanthin, ouabain etc.* MOA of Digitalis: binds to Na+K+ATPase of myocardial fibres and inhibits this enzyme. This leads to progressive accumulation of Na+ intracellularly which indirectly results in intracellular Calcium accumulation.* ACTION:# Digitalis increases the force of contraction and decreases the heart rate# It also decreases the AV conduction, hence contraindication in WPW syndrome.# Causes diuresis in CHF patients# Causes decrease in peripheral resistance in CHF patients (because of withdrawal of reflex sympathetic overactivity)
Increases cardiac contraction
Pumps sodium out of cell
Increases intracellular calcium
Causes bradycardia
Digitalis