Correct Answer: A

Rationale: The correct answer is A, heart failure. This condition occurs when the heart can't pump enough blood to fulfill the body's requirements. Myocardial infarction (choice B) is the medical term for a heart attack, which is caused by a blockage in the coronary arteries. Cardiomyopathy (choice C) is a disease of the heart muscle that makes it harder for the heart to pump blood. Pericarditis (choice D) is the inflammation of the pericardium, the thin sac-like membrane surrounding the heart, and does not specifically involve the heart's inability to pump sufficient blood.

Correct Answer: A

Rationale: The correct answer is Norepinephrine. Norepinephrine is the neurotransmitter released by the sympathetic nervous system that increases heart rate and the force of contraction. Epinephrine, though similar, is more involved in the fight-or-flight response and has a broader range of effects on various organs. Dopamine is not primarily responsible for increasing heart rate and contractility. Acetylcholine is a neurotransmitter that predominantly acts on the parasympathetic nervous system to decrease heart rate and contractility.

Correct Answer: B

Rationale: The correct answer is B because adding a beta blocker to digoxin can potentiate the bradycardic effect of digoxin, leading to serious complications such as heart block. This combination requires caution as it can significantly slow down the heart rate. Choices A, C, and D are not the best options to question in this scenario. Loop diuretics are commonly used with digoxin, a digoxin dose of 0.125 mg per day is within the typical range, and ACE inhibitors are often prescribed alongside digoxin for managing heart conditions.

Correct Answer: D

Rationale: The correct answer is D, Left ventricle. The left ventricle pumps oxygenated blood into the systemic circulation via the aorta. This chamber receives oxygen-rich blood from the left atrium and contracts forcefully to propel blood into the aorta, distributing it to the body. The other options, right atrium, left atrium, and right ventricle, do not directly eject blood into the systemic arterial circulation via the aorta. The right atrium receives deoxygenated blood from the body, the left atrium receives oxygenated blood from the lungs, and the right ventricle pumps blood to the lungs for oxygenation.

Correct Answer: A

Rationale: The correct answer is A: Diuretic therapy. Diuretic therapy involves the use of medications that help remove excess fluid from the body, often used to treat conditions like pulmonary edema. Choice B, Oxygen therapy, is used to provide oxygen to patients with breathing difficulties but does not involve removing fluid from the lungs. Choice C, Inhaler therapy, is used to deliver medication directly to the lungs to help with respiratory conditions but does not focus on removing fluid. Choice D, Antihistamine therapy, is used to treat allergies by blocking histamine but is not related to removing fluid from the lungs.