Which medication is commonly used to reduce preload and afterload in heart failure?

Choice A rationale Digoxin is a cardiac glycoside that increases myocardial contractility and stroke volume, leading to improved cardiac output. It primarily affects the heart's pumping ability and heart rate, but it is not the main drug used to reduce both preload and afterload. Its role is more to manage symptoms of heart failure and improve cardiac output. Choice B rationale ACE inhibitors (e.g., lisinopril) work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This leads to vasodilation, which decreases both systemic vascular resistance (afterload) and venous pressure (preload), making them a cornerstone for treating heart failure and reducing the workload on the heart. Choice C rationale Beta-blockers (e.g., carvedilol) block the effects of epinephrine and norepinephrine on beta receptors, leading to a decrease in heart rate and contractility. This reduces myocardial oxygen demand and can improve ventricular remodeling over time in heart failure, but they do not primarily reduce both preload and afterload in the same way as ACE inhibitors. Choice D rationale Diuretics (e.g., furosemide) work by increasing the excretion of sodium and water from the body, which reduces blood volume. This primarily reduces preload (volume returned to the heart) and is used to manage symptoms like edema and congestion, but it is not as effective at reducing afterload as ACE inhibitors.