Final answer:
Digoxin is a positive inotropic agent that increases heart contraction strength and decreases HR without affecting BP. It inhibits the movement of calcium ions into the sarcoplasmic reticulum, resulting in increased intracellular calcium and more forceful contractions.
Step-by-step explanation:
The subject in question is digoxin, a medication used to manage certain heart conditions. Digoxin acts as a positive inotropic agent, which increases the force of heart contractions and thereby helps the heart pump more efficiently. This drug works by inhibiting the movement of calcium ions into the sarcoplasmic reticulum, leading to increased intracellular calcium levels, resulting in more forceful contractions. Simultaneously, digoxin decreases the heart rate (HR) without affecting blood pressure (BP). It is essential for maintaining electrolyte balance, and variations in sodium and potassium levels can have significant effects on heart function. Factors like hypoxia, acidosis, alkalosis, and hypothermia can also decrease HR, while thyroid hormones and glucagon have been known to increase cardiac rate and contractility.