Final answer:
Digoxin is known to strengthen heart contractions by increasing intracellular calcium but can lead to higher mortality when not used carefully.
Step-by-step explanation:
The “Promise Drug Trial” determined that Digoxin makes the heart squeeze stronger, but patients taking this drug die sooner. Digoxin acts as a positive inotropic agent by increasing the strength of the heart's contraction. It does so by inhibiting the ATPase that pumps calcium out of the cells of the heart muscle, leading to an increase in the intracellular concentration of calcium ions, which enhances the strength of myocardial contractions. However, despite these benefits, careful management of Digoxin is essential as it can lead to increased mortality if not properly monitored.