Correct Answer: A

Rationale: The correct answer is the Pulmonary valve. The Pulmonary valve prevents backflow of blood into the right ventricle from the pulmonary artery after it has been ejected. The Aortic valve (choice B) prevents backflow from the aorta into the left ventricle. The Tricuspid valve (choice C) prevents backflow of blood into the right atrium from the right ventricle. The Mitral valve (choice D) prevents backflow from the left ventricle into the left atrium.

Correct Answer: A

Rationale: The correct answer is an echocardiogram. This test utilizes sound waves to generate images of the heart, enabling doctors to evaluate both the function and structure of the heart. Choice B, MRI, uses magnetic fields and radio waves to produce detailed images of the body's organs and structures, not specifically focused on the heart. Choice C, CT scan, employs X-rays to create detailed cross-sectional images of the body, not primarily for the heart. Choice D, X-ray, uses electromagnetic radiation to produce images of internal structures, but it does not provide the detailed pictures of the heart's function that an echocardiogram does.

Correct Answer: A

Rationale: Ventricular hypertrophy is the correct answer. In ventricular hypertrophy, the walls of the heart's ventricles become thickened, which decreases the heart's efficiency in pumping blood. Atrial fibrillation (choice B) is an irregular and often rapid heart rate that can lead to poor blood flow. While restrictive cardiomyopathy (choice C) involves the heart muscle becoming rigid and less compliant, it is not specifically characterized by thickening of the ventricular walls. Cardiomyopathy (choice D) is a general term for diseases of the heart muscle, which can present with various symptoms and causes.

Correct Answer: A

Rationale: The correct answer is Thoracentesis. Thoracentesis is a procedure specifically designed to remove excess fluid or air from the pleural space in the chest. This process helps to relieve pressure on the lungs and improve breathing. Bronchoscopy (Choice B) is a procedure used to visualize the airways and diagnose lung conditions, not to remove fluid from the pleural space. Chest X-ray (Choice C) is an imaging test that provides a picture of the structures inside the chest, including the lungs, heart, and bones. Arterial blood gas (ABG) test (Choice D) is a blood test that measures the levels of oxygen and carbon dioxide in the blood, providing information about how well the lungs are working, but it does not involve removing excess fluid or air from the pleural space.

Correct Answer: B

Rationale: The correct answer is to hold the digoxin and notify the healthcare provider. A potassium level of 3.0 mEq/L indicates hypokalemia, which can increase the risk of digoxin toxicity. Digoxin and low potassium levels can lead to serious cardiac arrhythmias. Administering a potassium supplement (choice A) without healthcare provider guidance can worsen the situation. Continuing the current digoxin dose (choice C) can further increase the risk of toxicity. Administering Digibind (choice D) is used in severe cases of digoxin toxicity, not for addressing low potassium levels.