- Which of the following laboratory tests would be most useful for diagnosing a reinfarction at this time?
Answer: Creatine kinase-MB (CK-MB)
Troponin levels can remain elevated for 7 to 10 days following a myocardial infarction, making them less useful for detecting an early reinfarction. CK-MB levels, however, typically rise within 4-6 hours, peak around 24 hours, and return to baseline within 48-72 hours. Because of its shorter half-life, a new rise in CK-MB after it has started to decline is highly suggestive of reinfarction. Myoglobin rises very early but is nonspecific. BNP is a marker for heart failure.
- Which of the following findings in the patient's history is an absolute contraindication to this therapy?
Answer: Prior intracranial hemorrhage at any time
A history of any prior intracranial hemorrhage (ICH) is an absolute contraindication to fibrinolytic therapy due to the high risk of recurrent bleeding. Major surgery within the past 3 weeks is a relative contraindication. An ischemic stroke more than 3 months ago is a relative, not absolute, contraindication. Severe uncontrolled hypertension (systolic >180 mm Hg or diastolic >110 mm Hg) is a contraindication, but it can often be treated with antihypertensives to allow for fibrinolysis, making it a relative contraindication that can be mitigated.
- What is the most likely diagnosis?
Answer: Unstable angina
This patient's symptoms have changed from a stable pattern to one of increasing frequency and severity, now occurring at rest. This crescendo pattern and rest angina are hallmarks of unstable angina. Stable angina is characterized by predictable, exertional chest pain that is consistent over time. Non-ST-elevation myocardial infarction (NSTEMI) is excluded by the undetectable troponin level, which indicates no myocardial necrosis. Prinzmetal angina is caused by coronary vasospasm and typically occurs at rest, often during the night, but is less likely given the patient's preceding history of exertional symptoms.
- A 60-year-old man with anterior STEMI has chest pain for 90 minutes. ECG shows ST elevation V2–V5. He is eligible for PCI within 60 minutes. Which is the most appropriate initial treatment?
Answer: Activate PCI team and give antiplatelet therapy and anticoagulation promptly while preparing for emergent reperfusion.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of STEMI. The correct answer is A, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, B, fails because it overlooks that ECG is sufficient for activation in STEMI, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as ST elevation. Apply guideline-directed management, and avoid common pitfalls such as delaying reperfusion.
- In addition to anticoagulation with heparin, which of the following medications should be administered promptly?
Answer: Ticagrelor
Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor is a cornerstone of management for NSTEMI. For patients managed with an early invasive strategy, a potent P2Y12 inhibitor such as ticagrelor or prasugrel is recommended in addition to aspirin. Clopidogrel is an alternative. Abciximab is a glycoprotein IIb/IIIa inhibitor used adjunctively in the cath lab in specific high-risk situations. Reteplase is a fibrinolytic and is not indicated in NSTEMI. Warfarin is an oral anticoagulant used for long-term indications, not in acute ACS management.
- Administration of which of the following common anti-anginal medications is currently contraindicated?
Answer: Nitroglycerin
Sildenafil is a phosphodiesterase-5 (PDE-5) inhibitor used for erectile dysfunction. PDE-5 inhibitors potentiate the vasodilatory effects of nitrates, and their co-administration can lead to severe, refractory hypotension. Nitrates are contraindicated within 24 hours of sildenafil use. Therefore, nitroglycerin must be withheld. The other medications are not contraindicated by recent sildenafil use.
- A 55-year-old smoker has NSTEMI with elevated troponin and ST depressions. He reports black tarry stools today. Which is the most appropriate next step in management?
Answer: Withhold anticoagulation temporarily, stabilize possible GI bleed, and coordinate cardiology and GI for risk-balanced care.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of NSTEMI with active bleeding. The correct answer is B, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks the bleeding risk, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as melena and ST depressions. Apply guideline-directed management, and avoid common pitfalls such as ignoring comorbidities.
- What is the most appropriate reperfusion strategy for this patient?
Answer: Immediately transfer for primary PCI
For patients with STEMI, primary percutaneous coronary intervention (PCI) is the preferred reperfusion strategy if it can be performed in a timely fashion. The guideline-recommended goal for first medical contact-to-device time is less than 120 minutes. Since the estimated time for this patient is 75 minutes, which is well within the acceptable window, immediate transfer for primary PCI is the superior strategy. Fibrinolysis would be considered if the anticipated delay to PCI were longer (>120 minutes).
- Which of the following is the most appropriate immediate action?
Answer: Activate the cardiac catheterization laboratory for emergent PCI
According to current guidelines, a new or presumed new left bundle branch block (LBBB) in a patient with symptoms consistent with acute coronary syndrome is considered a STEMI equivalent. This patient requires immediate reperfusion therapy. The preferred reperfusion strategy is emergent percutaneous coronary intervention (PCI). Delaying treatment to await biomarker results or perform a stress test would increase morbidity and mortality. Diltiazem is contraindicated as it is a negative inotrope and could be harmful in an acute MI.
- A 60-year-old man with STEMI receives aspirin and is headed to PCI. He has SpO2 98% on room air and no respiratory distress. Which is the most appropriate initial treatment regarding oxygen?
Answer: Withhold supplemental oxygen because routine oxygen is not indicated when saturation is adequate and patient is stable.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of STEMI. The correct answer is B, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks evidence that routine oxygen may harm when SpO2 is normal, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as adequate saturation. Apply guideline-directed management, and avoid common pitfalls such as overuse of supplemental oxygen.
- Which of the following is the most likely diagnosis?
Answer: Non-ST-elevation myocardial infarction (NSTEMI)
The diagnosis of NSTEMI is made based on the presence of symptoms consistent with acute coronary syndrome (rest pain), along with objective evidence of myocardial necrosis (elevated and rising cardiac biomarkers) in the absence of ST-segment elevation on ECG. This patient has all these features. Unstable angina would present similarly but with normal cardiac biomarkers. STEMI requires persistent ST-segment elevation. Stable angina is chronic, predictable, and exertional.
- A 55-year-old smoker with NSTEMI is started on aspirin and heparin. He has persistent chest pain despite nitrates and dynamic ST depressions. Which is the most appropriate next step in management?
Answer: Proceed with early invasive strategy including coronary angiography due to refractory ischemia and high-risk features.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of NSTEMI with refractory symptoms. The correct answer is B, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks high-risk features requiring invasive strategy, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as persistent pain and dynamic ST changes. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of refractory ischemia.
- Which of the following is the most appropriate immediate next step in management?
Answer: Administer an intravenous fluid bolus
The clinical triad of hypotension, jugular venous distention, and clear lungs in a patient with an inferior MI is highly suggestive of right ventricular (RV) infarction. RV infarction leads to impaired filling of the left ventricle, making these patients highly dependent on preload. Nitrates decrease preload and can cause profound hypotension. The immediate treatment is to administer an intravenous fluid bolus to increase RV preload and improve cardiac output. Furosemide would be harmful by further reducing preload. Norepinephrine may be needed if hypotension persists despite fluid resuscitation.
- In addition to obtaining cardiac biomarkers and providing supplemental oxygen if needed, which of the following is the most appropriate initial pharmacologic intervention?
Answer: Chewable aspirin
For any patient with suspected Acute Coronary Syndrome (ACS), immediate administration of chewable aspirin (162-325 mg) is a Class I recommendation as it inhibits platelet aggregation and has been shown to reduce mortality. Sublingual nitroglycerin is appropriate for symptomatic relief of ischemic chest pain but does not provide a mortality benefit. Intravenous beta-blockers like metoprolol are typically administered within the first 24 hours but are not the most critical first step and should be used with caution in patients with signs of heart failure. Intravenous alteplase is a fibrinolytic agent indicated for STEMI, not for NSTEMI, which is suggested by the ST depressions on ECG.
- A 60-year-old man with STEMI receives aspirin and heparin. He has rales and S3; BP 92/58. ECG shows anterior ST elevation. Which is the most appropriate initial treatment?
Answer: Activate emergent PCI and start vasopressor/inotrope support as needed for cardiogenic shock physiology.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of STEMI with cardiogenic shock. The correct answer is C, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks the contraindication of nitrates in hypotension, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as rales, S3, and ST elevation. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of shock physiology.
- A 65-year-old man has chest pain at rest for 20 minutes, now resolved. ECG shows new ST depression in V5–V6; troponin is negative. Which of the following is the most likely diagnosis?
Answer: Unstable angina with ischemic ECG changes and negative biomarkers indicating no myocardial necrosis.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of unstable angina. The correct answer is A, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, B, fails because it overlooks that troponin is negative, distinguishing from NSTEMI, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as resolved pain and ST depression. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of ECG findings.
- Which of the following is the most appropriate next step in diagnosis?
Answer: Exercise electrocardiography
The patient's symptoms are characteristic of stable angina: chest discomfort that is exertional, predictable, and relieved by rest. Since he is currently asymptomatic and hemodynamically stable, the appropriate next step is an outpatient evaluation to confirm coronary artery disease. An exercise ECG (stress test) is the standard initial non-invasive test for a patient with an intermediate pre-test probability of CAD who can exercise. Emergent ED transfer and troponin measurement are for acute coronary syndromes. Holter monitoring is used to evaluate for arrhythmias.
- A 60-year-old man has crushing chest pain radiating to the left arm with nausea. ECG shows ST elevation in V1–V4. Door-to-balloon time will be 150 minutes. Which is the most appropriate next step in management?
Answer: Administer fibrinolysis if no contraindications, plus antiplatelet therapy, because timely PCI is unavailable.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of STEMI. The correct answer is C, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks the preference for PCI when timely, but here it's delayed, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as ST elevation and door-to-balloon time. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of ECG findings.
- A 55-year-old man with HTN and hyperlipidemia has 45 minutes of substernal pressure with diaphoresis. ECG shows ST elevation in V2–V5; troponin pending. Which is the most appropriate next step in management?
Answer: Give aspirin and a P2Y12 inhibitor, activate emergent PCI, and administer anticoagulation while preparing for cath lab.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of STEMI. The correct answer is B, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks the need for emergent reperfusion in STEMI, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as ST elevation. Apply guideline-directed management, and avoid common pitfalls such as delaying PCI.
- A 55-year-old smoker has chest discomfort and elevated troponin without ST elevation. He is pain-free after nitroglycerin. Which of the following is the most appropriate next step in management?
Answer: Admit, start antithrombotic therapy, and risk-stratify for early invasive coronary angiography due to NSTEMI.
This question tests understanding and management of Acute Coronary Syndromes as per USMLE Step 2 CK standards. Acute Coronary Syndromes encompass conditions like STEMI, NSTEMI, and Unstable Angina, characterized by acute myocardial ischemia. In this scenario, the patient's symptoms and ECG findings are indicative of NSTEMI. The correct answer is B, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, A, fails because it overlooks the elevated troponin requiring admission, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as pain relief with nitroglycerin but positive biomarkers. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of symptom resolution.
