Correct Answer: A

Rationale: The correct answer is A: Myocardial infarction. Myocardial infarction, commonly known as a heart attack, is the condition where the heart muscle is damaged due to a lack of oxygen, typically caused by a blocked coronary artery. Angina (choice B) is chest pain or discomfort that occurs when the heart muscle doesn't receive enough oxygen-rich blood. Pericarditis (choice C) is the inflammation of the pericardium, the thin sac-like membrane surrounding the heart. Pulmonary embolism (choice D) is a blockage in one of the pulmonary arteries in the lungs, often caused by a blood clot.

Correct Answer: A

Rationale: The correct answer is to hold the digoxin and notify the healthcare provider. A potassium level of 2.7 mEq/L is considered low and can increase the risk of digoxin toxicity. Holding the medication and informing the healthcare provider is crucial to prevent adverse effects. Administering the digoxin as ordered (Choice B) would put the client at a higher risk for toxicity. Increasing the dose of digoxin (Choice C) is not appropriate when the client's potassium level is low. Administering potassium supplements (Choice D) may be necessary but is not the priority action in this situation.

Correct Answer: A

Rationale: The correct answer is A. The standard instruction for sublingual nitroglycerin during an episode of chest pain is to take one tablet every 5 minutes, up to three tablets. If the pain persists after taking three tablets, the client should seek emergency help. Choice B is incorrect because taking one tablet every hour is not the appropriate dosing for acute chest pain. Choice C is incorrect as taking two tablets immediately is not in line with the recommended dosing instructions. Choice D is incorrect because sublingual nitroglycerin should be placed under the tongue, not swallowed with water.

Correct Answer: A

Rationale: Emphysema is the correct answer as it is a chronic lung disease characterized by the gradual destruction of the alveoli, which are essential for oxygen exchange. This destruction leads to difficulty breathing and reduced oxygen levels in the blood. Bronchitis is an inflammation of the bronchial tubes, not specifically involving alveoli destruction. Pulmonary hypertension is a condition of high blood pressure in the arteries of the lungs, not directly related to alveoli destruction. Sarcoidosis is a disease characterized by the growth of tiny collections of inflammatory cells in different parts of the body, including the lungs, but it does not primarily involve the destruction of alveoli.

Correct Answer: A

Rationale: The correct answer is A: Preload. Preload is the degree of myocardial fiber stretch before contraction, influenced by the volume of blood returning to the heart. This parameter is related to the amount of blood in the ventricles at the end of diastole. Choice B, Afterload, refers to the pressure or resistance that the ventricles must overcome to eject blood. Choice C, Contractility, is the intrinsic ability of the heart muscle to contract. Choice D, Ejection fraction, is the percentage of blood pumped out of the ventricles with each contraction.