Acute Coronary Syndromes
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USMLE Step 2 CK › Acute Coronary Syndromes
A 55-year-old smoker has 2 hours of chest pressure. ECG shows ST depressions in II, III, aVF; troponin is elevated. Which of the following is the most likely diagnosis?
Acute pericarditis due to pleuritic pain with diffuse ST elevations and PR depressions on ECG.
NSTEMI due to subendocardial ischemia with elevated troponin and no persistent ST elevation on ECG.
Unstable angina due to transient thrombosis with normal cardiac biomarkers and no myocardial necrosis.
STEMI due to complete coronary occlusion with ST elevation in contiguous leads and reciprocal changes.
Stable angina due to fixed coronary stenosis causing exertional pain relieved by rest within minutes.
Explanation
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 C, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, D, fails because it overlooks the absence of ST elevation and elevated troponin, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as ST depressions and troponin elevation. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of ECG findings.
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?
NSTEMI because any ST depression automatically implies myocardial infarction regardless of troponin results.
STEMI because lateral ischemia typically presents with ST depression rather than ST elevation.
Unstable angina with ischemic ECG changes and negative biomarkers indicating no myocardial necrosis.
Stable angina because symptoms resolved and therefore cannot represent an acute coronary syndrome.
GERD because transient chest pain relieved spontaneously is most consistent with esophageal reflux disease.
Explanation
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.
A 55-year-old smoker has NSTEMI. ECG shows ST depressions; troponin is elevated. He has ongoing chest pain and bradycardia at 42/min with hypotension. Which is the most appropriate next step in management?
Administer IV beta-blocker immediately to reduce myocardial oxygen demand despite bradycardia and hypotension.
Give atropine and supportive care for symptomatic bradycardia while continuing ACS therapy and urgent evaluation.
Discontinue antiplatelet therapy because bradycardia indicates noncardiac chest pain and low ACS risk.
Order outpatient Holter monitoring only because arrhythmia evaluation precedes any ACS management decisions.
Administer thrombolysis because bradycardia signifies an occlusive MI requiring fibrinolysis regardless of ECG findings.
Explanation
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 bradycardia. 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 contraindication of beta-blockers in bradycardia and hypotension, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as low heart rate and ST depressions. Apply guideline-directed management, and avoid common pitfalls such as inappropriate antianginal use.
A 60-year-old man with anterior STEMI is going for PCI. He has no contraindications. Which is the most appropriate initial treatment in addition to aspirin?
Begin high-dose ibuprofen for pain control because it reduces inflammation and improves infarct healing.
Delay antithrombotic therapy until after coronary angiography confirms a culprit lesion requiring intervention.
Give prophylactic antibiotics because bacteremia is common during PCI and worsens myocardial injury.
Administer thrombolytics routinely before PCI because combined therapy is always superior to PCI alone.
Start dual antiplatelet therapy with a P2Y12 inhibitor and initiate anticoagulation while preparing for PCI.
Explanation
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 anti-inflammatory effects not being beneficial in ACS, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as anterior ST elevation. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of adjunct therapies.
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?
Administer fibrinolysis because elevated troponin confirms MI and thrombolysis is indicated for all MI types.
Order outpatient stress test only because absence of ST elevation indicates stable angina rather than ACS.
Admit, start antithrombotic therapy, and risk-stratify for early invasive coronary angiography due to NSTEMI.
Treat with NSAIDs and observe because pain relief with nitroglycerin excludes acute coronary syndrome.
Discharge with sublingual nitroglycerin because symptom relief indicates low risk and troponin elevation is nonspecific.
Explanation
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.
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?
Intubate early for airway protection because all STEMI patients require mechanical ventilation before PCI.
Administer high-flow oxygen routinely because it reduces infarct size in all patients with acute coronary syndrome.
Administer oxygen only after troponin results return because oxygen is contraindicated in NSTEMI.
Administer oxygen and delay PCI until saturation reaches 100% to minimize myocardial oxygen extraction.
Withhold supplemental oxygen because routine oxygen is not indicated when saturation is adequate and patient is stable.
Explanation
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.
A 65-year-old man has recurrent chest pain at rest, normal troponins, and no ST elevation. He is diagnosed with unstable angina. Which is the most appropriate initial treatment?
Provide reassurance and discharge because normal troponin excludes acute coronary syndrome and admission is unnecessary.
Treat with ibuprofen and schedule outpatient endoscopy because episodic pain suggests reflux disease.
Order exercise stress testing immediately during active symptoms to confirm ischemia before any medications.
Start aspirin and anticoagulation, add antianginal therapy, and admit for monitoring and further ischemic evaluation.
Administer thrombolytics because unstable angina is an early STEMI and requires immediate fibrinolysis.
Explanation
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 the risk despite normal troponin, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as recurrent rest pain. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of negative biomarkers.
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?
Discharge with outpatient cardiology follow-up because rales and S3 are common in anxiety-related chest pain.
Give IV fluids bolus and high-dose beta-blocker immediately to reduce myocardial oxygen demand.
Activate emergent PCI and start vasopressor/inotrope support as needed for cardiogenic shock physiology.
Start IV nitroglycerin titration aggressively to reduce preload despite hypotension and suspected cardiogenic shock.
Administer NSAIDs for chest pain and delay reperfusion until blood pressure stabilizes spontaneously.
Explanation
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 70-year-old diabetic woman presents with fatigue and dyspnea. ECG shows T-wave inversions; troponin is elevated. She is started on heparin. Platelets drop from 220k to 90k on day 5. Which is the most appropriate next step in management?
Continue heparin because thrombocytopenia is expected in ACS and does not affect anticoagulation choice.
Administer thrombolytics because thrombocytopenia suggests coronary thrombosis requiring fibrinolytic therapy urgently.
Give platelet transfusion routinely and continue heparin because transfusion prevents thrombosis in ACS patients.
Stop aspirin because thrombocytopenia indicates aspirin-induced platelet destruction and requires immediate cessation.
Stop heparin and start a non-heparin anticoagulant due to suspected HIT in the setting of platelet fall.
Explanation
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 suspected HIT. 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 risk of thrombosis in HIT, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as platelet drop on heparin. Apply guideline-directed management, and avoid common pitfalls such as continuing implicated anticoagulants.
A 70-year-old woman with diabetes has dyspnea and fatigue. ECG shows T-wave inversions; troponin is elevated. BP 168/92, HR 96. Which is the most likely diagnosis?
Unstable angina characterized by normal biomarkers and transient symptoms without evidence of myocardial necrosis.
Costochondritis characterized by reproducible chest wall tenderness and normal ECG and cardiac biomarkers.
STEMI characterized by ST elevation in contiguous leads and immediate need for reperfusion therapy.
Stable angina characterized by exertional chest pain relieved by rest and no biomarker elevation.
NSTEMI characterized by ischemic ECG changes and elevated cardiac biomarkers without persistent ST elevation.
Explanation
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 A, which aligns with current management guidelines and addresses the patient's immediate needs. A common distractor, B, fails because it overlooks the elevated troponin indicating necrosis, leading to inadequate management. To approach similar questions, identify key symptoms and diagnostic markers such as T-wave inversions and elevated troponin. Apply guideline-directed management, and avoid common pitfalls such as misinterpretation of ECG findings.