Correct Answer: A

Rationale: Angiography is the correct answer because it is an imaging test that specifically uses X-rays to visualize blood vessels by injecting them with a contrast dye. This procedure is crucial for diagnosing conditions such as blockages or aneurysms. The other options, CT scan, MRI, and ultrasound, do not involve the use of contrast dye to visualize blood vessels with X-rays.

Correct Answer: A

Rationale: Angiography is the correct answer because it is an imaging test that specifically uses X-rays to visualize blood vessels by injecting them with a contrast dye. This procedure is crucial for diagnosing conditions such as blockages or aneurysms. The other options, CT scan, MRI, and ultrasound, do not involve the use of contrast dye to visualize blood vessels with X-rays.

Correct Answer: A

Rationale: Afterload is the correct answer because it refers to the pressure or tension that the ventricle must overcome during systole to eject blood into the aorta. Preload, on the other hand, is the degree of stretch of the ventricular muscle at the end of diastole before it contracts. Automaticity is the ability of the heart to generate electrical impulses independently, and ejection fraction is the percentage of blood pumped out of the ventricle with each heartbeat. Therefore, in the context of the question, afterload best describes the amount of tension the ventricle must develop to eject blood into the aorta.

Correct Answer: D

Rationale: The correct answer is D: Decreases blood pressure. Calcium channel blockers primarily work by relaxing the blood vessels, leading to a decrease in blood pressure. Choice A, 'Decreases heart rate,' is incorrect because calcium channel blockers do not significantly affect heart rate. Choice B, 'Increases heart rate,' is incorrect as calcium channel blockers do not have a primary effect of increasing heart rate. Choice C, 'Increases blood pressure,' is incorrect as the primary effect of calcium channel blockers is to decrease blood pressure by vasodilation.

Correct Answer: A

Rationale: Cardiomyopathy is the correct answer. In cardiomyopathy, the heart muscle becomes weak and cannot pump blood effectively, which can lead to heart failure. Myocarditis (choice B) is inflammation of the heart muscle, not specifically causing muscle weakness. Endocarditis (choice C) is an infection of the inner lining of the heart chambers and valves. Pericarditis (choice D) is inflammation of the pericardium, the outer lining of the heart.