CCRN Cardiovascular Emergencies 2 — Questions and Answers
Question 1: A patient presents with crushing substernal chest pain and ST-segment elevation in leads II, III, and aVF. Which coronary artery is most likely occluded?
- Left anterior descending artery
- Right coronary artery (Correct answer)
- Left circumflex artery
- Left main coronary artery
Correct answer: Right coronary artery
ST elevation in II, III, and aVF indicates an inferior wall MI, typically caused by right coronary artery occlusion.
Question 2: In a patient with an inferior wall MI, why should nitroglycerin be administered cautiously?
- It may cause reflex tachycardia
- Right ventricular involvement makes the patient preload-dependent (Correct answer)
- It increases myocardial oxygen demand
- It worsens ST elevation
Correct answer: Right ventricular involvement makes the patient preload-dependent
Inferior MIs often involve the right ventricle, and nitroglycerin-induced preload reduction can cause severe hypotension.
Question 3: Which laboratory marker is most specific for myocardial injury?
- Myoglobin
- Troponin I (Correct answer)
- Creatine kinase (total)
- Lactate dehydrogenase
Correct answer: Troponin I
Troponin I is highly specific to cardiac muscle and is the preferred marker for diagnosing myocardial injury.
Question 4: A patient with an acute MI develops a new harsh holosystolic murmur and pulmonary edema 3 days post-infarction. What complication is most likely?
- Pericarditis
- Papillary muscle rupture (Correct answer)
- Ventricular aneurysm
- Atrial fibrillation
Correct answer: Papillary muscle rupture
A new holosystolic murmur with acute pulmonary edema post-MI suggests papillary muscle rupture causing acute mitral regurgitation.
Question 5: What is the primary goal of fibrinolytic therapy in STEMI when PCI is unavailable?
- Reduce afterload
- Dissolve the occluding thrombus and restore perfusion (Correct answer)
- Prevent reinfarction long-term
- Decrease myocardial oxygen demand
Correct answer: Dissolve the occluding thrombus and restore perfusion
Fibrinolytics break down the clot occluding the coronary artery to restore myocardial blood flow.
Question 6: Which finding is an absolute contraindication to fibrinolytic therapy?
- Age over 75
- Recent ischemic stroke within 3 months (Correct answer)
- Controlled hypertension
- Current anticoagulant use
Correct answer: Recent ischemic stroke within 3 months
Recent ischemic stroke within 3 months is an absolute contraindication due to high bleeding/conversion risk.
Question 7: A patient post-MI is started on a beta-blocker. What is the primary rationale?
- Increase contractility
- Reduce myocardial oxygen demand and prevent arrhythmias (Correct answer)
- Promote diuresis
- Dilate coronary arteries directly
Correct answer: Reduce myocardial oxygen demand and prevent arrhythmias
Beta-blockers lower heart rate and contractility, reducing oxygen demand and the risk of lethal arrhythmias.
CCRN Cardiovascular Emergencies 2
A patient presents with crushing substernal chest pain and ST-segment elevation in leads II, III, and aVF.
Which coronary artery is most likely occluded?