Correct Answer: C

Rationale: Seizures are the most concerning side effect of lidocaine IV administration due to its potential to indicate lidocaine toxicity, which can lead to serious complications such as cardiovascular collapse. Headache, nausea, and tremors are not typically associated with lidocaine IV and are less concerning compared to seizures in this context.

Correct Answer: B

Rationale: The correct answer is B, Left atrium. The left atrium receives oxygenated blood from the lungs via the four pulmonary veins and acts as a holding chamber before the blood is pumped into the left ventricle. Choice A, Right atrium, is incorrect as it receives deoxygenated blood from the body via the vena cava. Choices C and D, Right ventricle and Left ventricle, are incorrect as they receive blood from the atria, not the pulmonary veins.

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: The correct answer is A: Heart failure. Heart failure occurs when the heart is unable to pump blood effectively, resulting in a buildup of fluid in the lungs and other parts of the body. Choice B, Cardiomyopathy, refers to diseases of the heart muscle, not specifically the inability to pump blood effectively. Choice C, Myocardial infarction, is a heart attack caused by a blocked blood supply to the heart muscle, not directly related to the heart's pumping efficiency. Choice D, Pulmonary edema, is a condition characterized by fluid accumulation in the lungs, often a consequence of heart failure but not the primary condition described in the question.

Correct Answer: A

Rationale: Refractoriness is the correct term to describe the inability of cardiac cells to respond to a new stimulus while they are still in contraction from a previous stimulus. This period is essential for the heart to complete its contraction and relaxation phases without interference. Excitability refers to the ability of cells to respond to stimuli, not the inability to respond. Contractility is the force of cardiac muscle contraction, and automaticity is the ability of cardiac cells to generate electrical impulses spontaneously, which are not relevant to the described scenario.