"Digitalis lanata" contains a powerful cardiac glycoside that may be used by patients with heart conditions. Digoxin (digitalin) is a drug that is extracted from "D. lanata". It is used to treat some heart conditions such as atrial fibrillation and cardiac arrhythmias. Its cardiotonic effects slows atrioventricular conduction so that the heartbeat slows down and slightly increases contraction power (positive inotropic effect). Because of the improved circulation in congestive heart failure caused by fast atrial fibrillation, the kidneys can function better, which stimulates the flow of urine, which lowers the volume of the blood and lessens the load on the heart.