A 72-year-old man is having an electrocardiogram performed by his primary care physician to further evaluate intermittent chest pain. Regarding the phase 0 of the cardiac action potential, which of the following statements is true?

Correct Answer: C

Rationale: In this scenario, the correct answer is C) Sodium current can be blocked by quinidine in phase 0 of the cardiac action potential. Quinidine is a Class I antiarrhythmic drug that acts by blocking sodium channels, thereby inhibiting the influx of sodium ions during phase 0 of the cardiac action potential. By blocking sodium channels, quinidine decreases the rate of depolarization in cardiac cells, which can be beneficial in treating certain arrhythmias. Option A) Calcium channels opening resulting in outward current is incorrect because calcium channels primarily play a role in phase 2 of the cardiac action potential, not phase 0. Option B) Potassium channels rapidly opening and closing is incorrect as potassium channels are more active during phase 3 of the cardiac action potential, not phase 0. Option D) Transient outward current developing is also incorrect as transient outward potassium currents occur mainly during phases 1 and 2, not phase 0. Educationally, understanding the phases of the cardiac action potential and the mechanisms of action of antiarrhythmic drugs like quinidine is crucial for nursing students to provide safe and effective care to patients with cardiovascular conditions. It helps in making informed decisions regarding medication administration and monitoring for adverse effects.

Correct Answer: A

Rationale: In this scenario, the most appropriate choice for the 52-year-old man with chest pain would be Medication A. Nitroglycerin, which is a common cardiac nitrate used in such cases, has a rapid onset of action and short duration, making it effective for relieving acute chest pain. This medication helps dilate blood vessels, improving blood flow to the heart and reducing the workload on the heart muscle. Medication B and C may have different onset and duration profiles that may not be as suitable for the acute presentation of chest pain. Medication B might have a slower onset of action, while Medication C may have a longer duration of action, which may not be ideal for immediate relief in this urgent situation. Educationally, understanding the onset and duration of action of cardiac nitrates is crucial for nurses in emergency settings to provide prompt and effective care to patients presenting with chest pain. It is essential to know which medication is most appropriate based on the patient's clinical presentation to ensure optimal outcomes and patient safety. This knowledge helps nurses make informed decisions and deliver quality care in emergency situations, potentially saving lives.

Correct Answer: B

Rationale: In this quiz question, the correct answer is B) Is not effective when given by mouth. Rationale: A) Is effective in supraventricular and ventricular dysrhythmias: This statement is true. Sotalol is a non-selective beta-blocker that also exhibits class III antiarrhythmic properties, making it effective in treating both supraventricular and ventricular dysrhythmias. C) The dose should be reduced in renal impairment: This statement is true. Sotalol is renally excreted, so in patients with renal impairment, the dose should be adjusted to prevent drug accumulation and potential toxicity. D) May cause torsade de pointes: This statement is true. Sotalol can prolong the QT interval, leading to a higher risk of developing torsade de pointes, a potentially life-threatening ventricular arrhythmia. Educational Context: Understanding the pharmacological properties and considerations of cardiovascular drugs is essential for nursing practice. Sotalol is a medication commonly used to manage various dysrhythmias, so nurses must be knowledgeable about its indications, contraindications, side effects, and dosage adjustments based on individual patient factors. By grasping these concepts, nurses can safely administer and monitor patients receiving sotalol therapy, optimizing patient outcomes and minimizing adverse effects.

Correct Answer: D

Rationale: Nitroprusside is a medication commonly used for severe hypertension, but it can lead to severe toxicity if administered for extended periods or at high doses. The correct answer, D) Cyanide, is the main nitroprusside metabolite responsible for the toxicity. Nitroprusside is metabolized into cyanide in the body, which can lead to serious adverse effects such as refractoriness to antihypertensive effects, decreased blood pressure, and other symptoms of toxicity. Option A) A highly efficacious alpha-adrenergic agonist is incorrect because nitroprusside does not act as an alpha-adrenergic agonist. Option B) An extraordinarily potent and irreversible Na-K-ATPase inhibitor is incorrect as nitroprusside does not act on Na-K-ATPase. Option C) An irreversible agonist for angiotensin II receptors is incorrect as nitroprusside does not directly affect angiotensin II receptors. In an educational context, understanding the metabolism and potential toxic effects of medications like nitroprusside is crucial for safe administration and patient care. Nurses and healthcare providers must be aware of potential adverse effects, like cyanide toxicity, to monitor patients effectively and intervene promptly if needed. This knowledge ensures patient safety and quality care in clinical practice.