STEMI Flashcards
Which of the following descriptions best characterizes the pain associated with STEMI?
A. Sharp, localized, and worsens with deep inspiration
B. Heavy, squeezing, crushing, and may radiate to the arms
C. Sudden, tearing pain that radiates to the back
D. Dull pain that improves with leaning forward
✅ Answer: B
Rationale: STEMI pain is typically deep, visceral, heavy, squeezing, or crushing and often radiates to the arms, epigastrium, lower jaw, or neck. Answer choices A and D are more characteristic of pericarditis, while C suggests aortic dissection.
Which of the following differentiates STEMI pain from angina pectoris?
A. STEMI pain is typically relieved by rest and nitroglycerin
B. STEMI pain is usually more severe and prolonged
C. STEMI pain does not involve the central chest
D. STEMI pain never occurs at rest
✅ Answer: B
Rationale: Unlike angina, STEMI pain is more severe, prolonged, and often occurs at rest. Angina typically improves with rest or nitroglycerin, while STEMI pain persists despite cessation of activity.
Which of the following symptoms is more common in diabetic and elderly patients with STEMI?
A. Severe chest pain
B. Silent or atypical presentation (e.g., breathlessness, confusion)
C. Exertion-related chest discomfort
D. Radiation of pain to the occipital region
✅ Answer: B
Rationale: Diabetic and elderly patients often experience silent or atypical STEMI presentations, such as sudden breathlessness, confusion, or syncope, rather than classic chest pain.
What is a major drawback of using total CK levels for diagnosing STEMI?
A) Total CK levels peak too late for clinical utility.
B) Total CK levels are not affected by myocardial infarction.
C) Total CK lacks specificity since it can be elevated in skeletal muscle injuries.
D) Total CK takes longer to return to baseline compared to cTnT and cTnI.
Correct Answer: C
Rationale: Total CK levels can be elevated due to skeletal muscle disease, trauma, or intramuscular injections, making it a less specific marker for myocardial infarction compared to CK-MB or cardiac-specific troponins.
Which of the following inflammatory responses is commonly seen after STEMI?
A) A decrease in white blood cell count within the first 24 hours.
B) An increase in polymorphonuclear leukocytes within hours of symptom onset.
C) A rapid drop in erythrocyte sedimentation rate (ESR) within 24 hours.
D) A persistent reduction in leukocyte count for 7–10 days.
Correct Answer: B
Rationale: Polymorphonuclear leukocytosis occurs within a few hours of STEMI onset and persists for 3–7 days, with white blood cell counts reaching 12,000–15,000/μL. The ESR rises more slowly, peaking within the first week and remaining elevated for 1–2 weeks.
What is the most common cause of out-of-hospital deaths in STEMI patients?
A) Cardiogenic shock
B) Ventricular fibrillation
C) Pulmonary embolism
D) Aortic dissection
Correct Answer: B
Rationale: Ventricular fibrillation is the most common cause of sudden cardiac death in STEMI patients. Most deaths due to ventricular fibrillation occur within the first 24 hours, with over half occurring in the first hour after symptom onset.
Which type of MI is specifically related to percutaneous coronary intervention (PCI)?
A) Type 1 MI
B) Type 3 MI
C) Type 4a MI
D) Type 5 MI
Answer: C) Type 4a MI
Rationale:
Type 4a MI is specifically associated with percutaneous coronary intervention (PCI). Type 5 MI is related to coronary artery bypass grafting (CABG), while Type 1 MI is the classic spontaneous MI due to plaque rupture, and Type 3 MI refers to sudden cardiac death before biomarker confirmation.
A patient who has undergone coronary artery bypass grafting (CABG) is diagnosed with a type 5 MI. What is the required elevation of cardiac biomarkers for this diagnosis?
A) 2× the 99th percentile URL
B) 5× the 99th percentile URL
C) 10× the 99th percentile URL
D) 20× the 99th percentile URL
Answer: C) 10× the 99th percentile URL
Rationale:
Type 5 MI, which is CABG-related, requires a rise of cardiac biomarkers to at least 10 times the 99th percentile URL, along with ischemic symptoms, ECG changes, angiographic findings, or imaging evidence of myocardial damage
What is the recommended time frame for initiating percutaneous coronary intervention (PCI) from the first medical contact?
A) Within 30 minutes
B) Within 60 minutes
C) Within 90 minutes
D) Within 120 minutes
Answer: D) Within 120 minutes
Rationale:
The goal is to initiate PCI within 120 minutes of first medical contact, especially if the patient requires transfer to a PCI-capable hospital. Faster intervention improves outcomes.
What is the preferred initial dose of aspirin in suspected STEMI patients in the emergency department?
A) 75–162 mg swallowed whole
B) 160–325 mg chewed
C) 81 mg enteric-coated
D) 500 mg dissolved in water
Answer: B) 160–325 mg chewed
Rationale:
Chewing 160–325 mg of aspirin allows for rapid absorption and inhibition of thromboxane A2, reducing platelet aggregation. Enteric-coated or lower doses take longer to take effect.
Which of the following statements about oxygen therapy in STEMI is correct?
A) Oxygen should be given to all patients regardless of oxygen saturation
B) Oxygen is only beneficial in patients with hypoxemia
C) High-flow oxygen (≥10 L/min) should be used in all STEMI cases
D) Oxygen should be given for at least 48 hours in all STEMI patients
Answer: B) Oxygen is only beneficial in patients with hypoxemia
Rationale:
Routine oxygen therapy is not recommended unless the patient is hypoxemic. When needed, low-flow oxygen (2–4 L/min) should be used for the first 6–12 hours, followed by reassessment.
Which of the following is a primary mechanism by which nitroglycerin helps in STEMI management?
A) Increases heart rate to improve cardiac output
B) Lowers preload and dilates infarct-related coronary vessels
C) Directly dissolves coronary thrombi
D) Stimulates vagal tone to slow conduction
Answer: B) Lowers preload and dilates infarct-related coronary vessels
Rationale:
Nitroglycerin reduces myocardial oxygen demand by decreasing preload and dilates coronary vessels to improve oxygen supply. It does not dissolve thrombi (which is the role of thrombolytics) or directly affect heart rate and vagal tone.
Which of the following patients should avoid nitroglycerin therapy in the setting of STEMI?
A) A patient with anterior STEMI and a systolic BP of 110 mmHg
B) A patient with inferior STEMI and signs of right ventricular infarction
C) A patient with a history of coronary artery disease but no active chest pain
D) A patient who received aspirin and clopidogrel in the emergency department
Answer: B) A patient with inferior STEMI and signs of right ventricular infarction
Rationale:
Nitroglycerin is contraindicated in RV infarction because it can exacerbate hypotension due to preload dependence. It is also avoided in hypotensive patients (SBP < 90 mmHg) and those who have taken a phosphodiesterase-5 inhibitor in the past 24 hours.
Which of the following is a contraindication to beta-blocker therapy in the first 24 hours of STEMI?
A) Systolic blood pressure of 110 mmHg
B) Presence of second-degree AV block
C) Heart rate of 75 beats per minute
D) Mild anterior ST-elevation on ECG
Answer: B) Presence of second-degree AV block
Rationale:
Beta blockers should not be given to patients with heart block (PR interval >0.24 s, second- or third-degree AV block), signs of heart failure, low-output state, or increased risk of cardiogenic shock.
A STEMI patient arrives at a PCI-capable hospital. What is the goal first medical contact (FMC) to device time for primary PCI?
A) ≤30 minutes
B) ≤60 minutes
C) ≤90 minutes
D) ≤120 minutes
Answer: C) ≤90 minutes
Rationale:
For a patient at a PCI-capable hospital, the goal FMC-to-device time should be ≤90 minutes to ensure timely reperfusion and limit myocardial damage (Class I, LOE: A).
A STEMI patient presents to a non–PCI-capable hospital, and the anticipated time for primary PCI is more than 120 minutes. What is the recommended next step?
A) Immediate coronary artery bypass grafting (CABG)
B) Administer a fibrinolytic agent within 30 minutes
C) Observe the patient and reassess in 12 hours
D) Perform an immediate diagnostic angiogram
Answer: B) Administer a fibrinolytic agent within 30 minutes
Rationale:
If the anticipated FMC-to-PCI time is >120 minutes, fibrinolytic therapy should be administered within 30 minutes to reduce infarct size and mortality (Class I, LOE: B).
A STEMI patient at a non–PCI-capable hospital received fibrinolytic therapy. What is the next recommended step for this patient?
A) Urgent transfer for PCI if there is evidence of failed reperfusion or reocclusion
B) Immediate CABG
C) Discharge with medical therapy only
D) No need for further intervention if the patient is pain-free
Answer: A) Urgent transfer for PCI if there is evidence of failed reperfusion or reocclusion
Rationale:
If a patient receives fibrinolysis but has failed reperfusion or reocclusion, urgent PCI is recommended (Class IIa, LOE: B). If successful fibrinolysis occurs, angiography within 3–24 hours is advised as part of an invasive strategy.
A STEMI patient at a non–PCI-capable hospital has cardiogenic shock. What is the best management strategy?
A) Immediate administration of fibrinolytics
B) Observation and reassessment after 24 hours
C) Transfer to a PCI-capable hospital as soon as possible, regardless of time delay
D) Treat with medical therapy only
Answer: C) Transfer to a PCI-capable hospital as soon as possible, regardless of time delay
Rationale:
Patients with cardiogenic shock or severe heart failure should be transferred immediately for PCI, regardless of time delay, as revascularization improves survival (Class I, LOE: B).
Which of the following is a clear contraindication to fibrinolytic therapy in STEMI?
A) Systolic blood pressure >180 mmHg
B) Diabetes mellitus
C) Chronic kidney disease
D) History of controlled hypertension
Answer:
✅ A) Systolic blood pressure >180 mmHg
Rationale:
Marked hypertension (SBP >180 mmHg or DBP >110 mmHg) is a contraindication due to the risk of intracranial hemorrhage. Other contraindications include prior intracranial hemorrhage, recent stroke, active bleeding, or suspected aortic dissection.
A STEMI patient undergoes angiography after receiving fibrinolysis. The infarct-related artery shows TIMI grade 2 flow. What does this indicate?
A) Complete occlusion
B) Delayed perfusion of the distal vessel
C) Normal perfusion
D) No penetration of contrast beyond the obstruction
Answer:
✅ B) Delayed perfusion of the distal vessel
Rationale:
TIMI grade 2 means the artery is partially reperfused, but blood flow is delayed. TIMI grade 3 is the goal, indicating normal perfusion.
Which of the following conditions is considered a relative contraindication to fibrinolytic therapy?
A) Active internal bleeding
B) A history of severe but controlled hypertension
C) Prior hemorrhagic stroke
D) Suspected aortic dissection
✅ Answer: B) A history of severe but controlled hypertension
Rationale:
Absolute contraindications include active bleeding, prior hemorrhagic stroke, and aortic dissection (A, C, D).
Controlled hypertension is a relative contraindication, meaning fibrinolysis may still be considered if the benefits outweigh the risks.
Which of the following is an indication for rescue PCI after fibrinolytic therapy?
A) Resolution of chest pain within 30 minutes
B) ST-segment elevation persists >90 minutes
C) Absence of coronary artery disease on ECG
D) Mild chest discomfort without ECG changes
✅ Answer: B) ST-segment elevation persists >90 minutes
Rationale:
Rescue PCI is indicated if there is failure of reperfusion, which is defined as persistent ST-segment elevation >90 minutes despite fibrinolysis.
Resolution of chest pain (A) suggests successful reperfusion.
If no coronary artery disease is present (C), PCI is not needed.
Mild chest discomfort (D) without ECG changes does not indicate failed reperfusion.
Which scenario requires urgent PCI following fibrinolytic therapy?
A) Recurrent ST-segment elevation and chest pain
B) No ST-segment changes but mild fatigue
C) Asymptomatic patient with normal ECG
D) Mild T-wave inversions on ECG without symptoms
✅ Answer: A) Recurrent ST-segment elevation and chest pain
Rationale:
Urgent PCI is indicated for coronary artery reocclusion, which presents as recurrent ST-segment elevation and chest pain.
Fatigue (B), asymptomatic cases (C), and isolated T-wave changes (D) do not necessarily require urgent PCI unless accompanied by signs of ischemia.
What is the recommended diet for patients within the first 4–12 hours after STEMI?
A) High-protein diet to promote healing
B) Low-fat diet with ≤30% of calories from fat
C) Clear liquids or nothing by mouth
D) Carbohydrate-rich diet to provide energy
✅ Answer: C) Clear liquids or nothing by mouth
Rationale:
Due to the risk of emesis and aspiration, patients should receive only clear liquids or nothing by mouth in the initial hours.
Because of the risk of emesis and aspiration soon after STEMI, patients should receive either nothing or only clear liquids by mouth or the first 4–12 h. The typical coronary care unit diet should provide ≤30% of total calories as fat and have a cholesterol content of ≤300 mg/d. Complex carbohydrates should make up 50–55% of total calories.
Which of the following is true about early mobilization in STEMI patients?
A) Patients should remain in bed for the first 5 days
B) Ambulation should start within 24 hours if no complications arise
C) Early mobilization increases pulmonary congestion
D) Patients should avoid sitting in a chair for psychological reasons
✅ Answer: B) Ambulation should start within 24 hours if no complications arise
Rationale:
Early mobilization reduces pulmonary capillary wedge pressure and improves recovery.
What is the recommended bowel management strategy for STEMI patients on bed rest?
A) Bedpan use for all patients
B) Diet rich in fiber with a stool softener
C) Strict avoidance of rectal exams
D) Laxative use in all patients immediately after admission
✅ Answer: B) Diet rich in fiber with a stool softener
Rationale:
Constipation is common due to bed rest and narcotics, so fiber-rich diets and stool softeners are recommended.
What is the primary mechanism by which ACE inhibitors reduce mortality in STEMI patients?
A) Reduction in ventricular remodeling
B) Immediate increase in ejection fraction
C) Direct inhibition of platelet aggregation
D) Decreasing myocardial oxygen demand
✅ Answer: A) Reduction in ventricular remodeling
Rationale:
ACE inhibitors limit ventricular remodeling, reducing the risk of heart failure and future infarctions.
Which group of STEMI patients benefits the most from ACE inhibitors?
A) Young patients with inferior infarction
B) Patients with hypertension only
C) High-risk patients with anterior infarction, prior infarction, or reduced LV function
D) Patients with normal LV function and no risk factors
✅ Answer: C) High-risk patients with anterior infarction, prior infarction, or reduced LV function
Rationale:
Elderly patients, those with large infarcts (especially anterior wall), prior infarcts, or low EF derive the most benefit from ACE inhibitors.
While all hemodynamically stable patients can be considered for ACE inhibitors, high-risk groups show the greatest mortality reduction.
evidence suggests that a shortterm
benefit occurs when ACE inhibitors are prescribed unselectively to all hemodynamically stable patients with STEMI (i.e., those with a
systolic pressure >100 mmHg). The mechanism involves a reduction in ventricular remodeling after infarction (see “Ventricular Dysfunction”
later) with a subsequent reduction in the risk of CHF.
Which mineralocorticoid receptor antagonist (MRA) should be prescribed post-STEMI for heart failure patients already on an ACE inhibitor?
A) Spironolactone or eplerenone
B) Furosemide
C) Diltiazem
D) Digoxin
✅ Answer: A) Spironolactone or eplerenone
Rationale:
Spironolactone and eplerenone improve survival in heart failure patients post-STEMI, especially if EF ≤40% with symptomatic HF or diabetes.
Long-term mineralocorticoid receptor inhibition (spironolactone, eplerenone) should be prescribed for STEMI patients without significant renal dysfunction (creatinine ≥2.5 mg/dL in men and ≥2.0 mg/dL in women) or hyperkalemia
(potassium ≥5.0 mEq/L) who are already receiving therapeutic doses of an ACE inhibitor, have an LV ejection fraction ≤40%, and have either symptomatic heart failure or diabetes mellitus.
Which of the following is the primary cause of in-hospital death from STEMI?
a) Arrhythmia
b) Pump failure
c) Myocardial infarction
d) Coronary artery spasm
Answer: b) Pump failure
Rationale: Pump failure is now recognized as the primary cause of in-hospital death from STEMI. This is due to the extent of infarction correlating with the degree of pump failure and mortality rates.
Which of the following clinical signs is most commonly seen in patients with STEMI-related pump failure?
a) Bradycardia
b) Pulmonary rales and S3 and S4 gallop sounds
c) Tachycardia and fever
d) Abdominal pain and jaundice
Answer: b) Pulmonary rales and S3 and S4 gallop sounds
Rationale: The most common clinical signs of pump failure in STEMI are pulmonary rales and S3 and S4 gallop sounds, indicating heart failure and pulmonary congestion.
What is the hallmark hemodynamic finding in patients with pump failure due to STEMI?
a) Elevated left ventricular filling pressure and pulmonary artery pressure
b) Decreased cardiac output
c) Low systemic vascular resistance
d) Increased heart rate and blood pressure
Answer: a) Elevated left ventricular filling pressure and pulmonary artery pressure
Rationale: Elevated left ventricular filling pressure and pulmonary artery pressure are characteristic findings in STEMI-related pump failure, indicative of heart failure.
According to the Killip classification, what is the mortality rate for patients in class IV?
a) 0–5%
b) 10–20%
c) 35–45%
d) 85–95%
Answer: d) 85–95%
Rationale: The Killip classification categorizes patients into four classes based on the severity of heart failure. Class IV patients, who are in shock with a systolic pressure <90 mmHg, have a mortality rate of 85–95%, though this has decreased with advances in management.
What is a typical characteristic of class III heart failure in the Killip classification?
a) No signs of pulmonary or venous congestion
b) Tachypnea and S3 gallop
c) Pulmonary edema
d) Systolic blood pressure >90 mmHg
Answer: c) Pulmonary edema
Rationale: Class III in the Killip classification represents severe heart failure, characterized by pulmonary edema, which requires urgent medical management.
Hemodynamic evidence of abnormal global LV function appears
when contraction is seriously impaired in 20–25% of the left ventricle.
Infarction of ≥40% of the left ventricle usually results in cardiogenic
shock
In patients with STEMI, which of the following is most likely to benefit from diuresis?
a) Patients with elevated LV filling pressures (>22 mmHg) and normal cardiac indices
b) Patients with low LV filling pressures (<15 mmHg) and reduced cardiac indices
c) Patients with normal LV filling pressures and high cardiac indices
d) Patients with no symptoms of heart failure
Answer: a) Patients with elevated LV filling pressures (>22 mmHg) and normal cardiac indices
Rationale: Patients with elevated LV filling pressures (>22 mmHg) and normal cardiac indices typically benefit from diuresis to reduce fluid overload and alleviate symptoms of heart failure.
A patient with STEMI presents with markedly elevated LV filling pressures (>22 mmHg) and normal cardiac indices. What is the likely treatment approach?
a) Diuresis
b) Volume expansion
c) Vasopressor therapy
d) Anti-arrhythmic drugs
Answer: a) Diuresis
Rationale: For patients with elevated LV filling pressures and normal cardiac indices, diuresis is typically used to reduce fluid overload and improve heart function.
What is the typical target for left ventricular (LV) filling pressure in STEMI patients during fluid resuscitation?
a) 10 mmHg
b) 15 mmHg
c) 20 mmHg
d) 30 mmHg
Answer: c) 20 mmHg
Rationale: The optimal LV filling pressure for patients with STEMI is generally around 20 mmHg. It is reached cautiously through fluid administration while monitoring oxygenation and cardiac output.
What is the target serum potassium concentration to reduce the risk of ventricular fibrillation in STEMI patients?
a) 3.0 mmol/L
b) 3.5 mmol/L
c) 4.5 mmol/L
d) 5.0 mmol/L
Answer: c) 4.5 mmol/L
Rationale: The serum potassium concentration should be adjusted to approximately 4.5 mmol/L to reduce the risk of ventricular fibrillation in patients with STEMI.
What is the target serum magnesium concentration to reduce the risk of ventricular fibrillation in STEMI patients?
a) 1.0 mmol/L
b) 1.5 mmol/L
c) 2.0 mmol/L
d) 2.5 mmol/L
Answer: c) 2.0 mmol/L
Rationale: The target serum magnesium concentration should be adjusted to approximately 2.0 mmol/L to reduce the risk of ventricular fibrillation in STEMI patients.
When is a maximal (symptom-limited) exercise stress test typically performed after STEMI?
a) Immediately after infarction
b) 1–2 weeks after infarction
c) 4–6 weeks after infarction
d) 6–12 months after infarction
Answer: c) 4–6 weeks after infarction
Rationale: A maximal (symptom-limited) exercise stress test is usually performed 4–6 weeks after STEMI to assess exercise tolerance and detect any remaining ischemia or arrhythmias.
When can normal sexual activity typically be resumed after STEMI?
a) Immediately after discharge
b) Within the first week after discharge
c) During the first 1–2 weeks after infarction
d) After 6 weeks
Answer: c) During the first 1–2 weeks after infarction
Rationale: Normal sexual activity can generally be resumed within the first 1–2 weeks after STEMI, provided there are no significant complications.
After 2 weeks post-STEMI, how should a patient’s activity be regulated?
a) Based solely on the patient’s preferences
b) By monitoring blood pressure during exercise
c) Based on exercise tolerance as guided by the physician
d) By avoiding any physical activity until 4 weeks have passed
Answer: c) Based on exercise tolerance as guided by the physician
Rationale: After 2 weeks, the patient’s activity level should be regulated based on their exercise tolerance and the physician’s guidance to ensure safe recovery.
How long after STEMI can most patients return to work?
a) 1–2 weeks
b) 2–4 weeks
c) 4–6 weeks
d) 6–12 weeks
Answer: b) 2–4 weeks
Rationale: Most patients can return to work within 2–4 weeks after STEMI, depending on their recovery and exercise tolerance.
