A client asks the nurse what cardiac glycosides do to relieve the symptoms of heart failure. What is the nurse's best response?

A. "They make your heart contract more forcefully.": Cardiac glycosides, like digoxin, work by increasing the force of myocardial contractions. This improves the heart's ability to pump blood, which is beneficial in heart failure, where the heart's pumping ability is compromised. B. "They increase your blood pressure by reducing your urine output.": Cardiac glycosides do not directly increase blood pressure or reduce urine output. While they improve cardiac function, they do not have a primary diuretic effect like other medications such as diuretics. C. "They increase your heart rate.": Cardiac glycosides actually slow the heart rate, particularly in the context of heart failure, by affecting the electrical conduction system. This slowing of the heart rate (through vagal stimulation) helps improve the heart's efficiency. D. "They increase the velocity of the heart's electrical conduction.": Cardiac glycosides do not increase the velocity of electrical conduction. In fact, they can have the opposite effect by slowing conduction through the AV node, which helps in controlling certain arrhythmias.