STEMI Flashcards
Which histologic feature is commonly associated with coronary plaques prone to disruption in STEMI?
A. Thick fibrous cap with a low lipid core
B. Thin fibrous cap with a rich lipid core
C. Absence of a fibrous cap with extensive calcification
D. Intact endothelium with minimal inflammatory cells
B
Which of the following most accurately describes the typical mechanism of STEMI?
A. Gradual occlusion of a high-grade coronary artery stenosis due to collateral network failure
B. Abrupt decrease in coronary blood flow after a thrombotic occlusion of an atherosclerotic coronary artery
C. Coronary artery spasm in the absence of atherosclerosis
D. Acute embolization from an intracardiac thrombus causing coronary obstruction
B
The activation of which receptor on platelets promotes cross-linking and aggregation in STEMI?
A. Thromboxane A2 receptor
B. Glycoprotein IIb/IIIa receptor
C. ADP receptor
D. Serotonin receptor
B
Which of the following factors contributes to the disruption of atherosclerotic plaques, favoring thrombogenesis in STEMI?
A. Collagen vascular disease
B. Cigarette smoking
C. High levels of physical activity
D. Advanced age without comorbid conditions
B
What is the role of thrombin in the pathophysiology of STEMI following acute plaque rupture?
A. Thrombin inhibits platelet activation, reducing thrombus formation.
B. Thrombin converts fibrinogen to fibrin, stabilizing the developing thrombus.
C. Thrombin activates Factor X only, limiting the extent of the thrombus.
D. Thrombin prevents tissue factor exposure, reducing coagulation.
B
Which of the following statements is true regarding the onset of STEMI?
A. STEMI usually occurs during periods of deep sleep.
B. STEMI is commonly triggered by factors like vigorous exercise, emotional stress, or a recent medical illness.
C. STEMI is primarily seen in the evening hours.
D. The majority of STEMI cases have no identifiable precipitating factors.
B
Which characteristic best describes the typical pain experienced by patients with STEMI?
A. Sharp and localized to a single area
B. Mild discomfort relieved by rest
C. Deep, visceral pain that is heavy, squeezing, or crushing in nature
D. Limited to the lower abdomen and always radiates to the legs
C
Radiation of STEMI pain to which of the following areas would suggest an alternative diagnosis, such as acute pericarditis?
A. Right arm
B. Left jaw
C. Trapezius muscle
D. Lower back
C
Which of the following groups is more likely to experience a painless presentation of STEMI?
A. Young patients without comorbidities
B. Patients with diabetes mellitus and elderly patients
C. Middle-aged adults with hypertension
D. Patients with a prior history of pericarditis
B
n elderly patients, which of the following symptoms may be an atypical presentation of STEMI?
A. Crushing chest pain radiating to the left arm
B. Sudden-onset breathlessness progressing to pulmonary edema
C. Mild chest discomfort that improves with rest
D. Chest pain that radiates to the lower abdomen
B
The combination of ____ persisting for >30 min and ____ strongly suggests STEMI.
substernal chest pain
diaphoresis
Patients with ____ infarction may have manifestations of sympathetic nervous system hyperactivity (tachycardia and/or hypertension), and those with ____infarction may show evidence of parasympathetic hyperactivity (bradycardia and/or hypotension).
anterior
inferior
Signs of Ventricular Dysfunction:
>__ and __ heart sounds
>Decreased intensity of the __ heart sound.
>Paradoxical splitting of the __ heart sound.
> 4th and 3rd
> 1st
> 2nd
Temperature may elevate up to 38°C during the ___ week after STEMI.
first
Systolic Blood Pressure:
Variable but often declines by ~10–15 mmHg from the preinfarction state in patients with ___infarction.
transmural
Patients with an anterior STEMI are more likely to exhibit which of the following findings within the first hour of presentation?
A. Bradycardia and hypotension
B. Tachycardia and hypertension
C. Bradycardia and hypertension
D. Tachycardia and hypotension
B
Which physical finding may suggest ventricular dysfunction in a patient with STEMI?
A. Increased intensity of the first heart sound
B. Paradoxical splitting of the second heart sound
C. Systolic pressure rise of 10–15 mmHg
D. Absence of third and fourth heart sounds
B
The presence of a pericardial friction rub in a patient with STEMI is most likely associated with which type of infarction?
A. Subendocardial STEMI
B. Transmural STEMI
C. Non-STEMI
D. Inferior wall STEMI without transmural involvement
B
In a patient with STEMI, a decrease in the carotid pulse volume is most indicative of which underlying issue?
A. Elevated systemic vascular resistance
B. Reduced stroke volume
C. Increased preload
D. Pulmonary congestion
B
Which of the following stages corresponds to the initial cellular response in the infarct zone of a STEMI?
A. Acute phase
B. Healing phase
C. Healed phase
D. Chronic phase
A
In the healing phase of STEMI (7–28 days), which cellular component is primarily involved in recruiting fibroblasts to the infarct zone?
A. Polymorphonuclear leukocytes
B. Reparative monocytes
C. Proinflammatory monocytes
D. Lymphocytes
C
During the healed phase of STEMI (≥29 days), what is the primary role of reparative monocytes in the infarcted myocardium?
A. Recruitment of polymorphonuclear leukocytes
B. Clearance of dead cells
C. Angiogenesis and interstitial collagen production
D. Activation of fibroblasts
C
T or F
Contemporary studies using magnetic resonance imaging (MRI) suggest that the development of a Q wave on the ECG is more dependent on the volume of infarcted tissue rather than the transmurality of infarction.
T
Which of the following is the primary electrocardiographic manifestation of total occlusion of an epicardial coronary artery in STEMI?
A. T-wave inversion
B. ST-segment elevation
C. Loss of R waves
D. Prolonged PR interval
B
Contemporary studies using MRI have shown that the development of Q waves on the ECG is more related to which of the following?
A. Transmurality of the infarction
B. Volume of infarcted tissue
C. Duration of the ischemic episode
D. Presence of collateral circulation
B
The criteria for AMI require a rise and/or fall in cardiac biomarker values with at least one value ____ of the upper reference limit for normal individuals.
above the 99th percentile
Which of the following best explains how serum cardiac biomarkers become detectable in the peripheral blood following STEMI?
A. Increased cardiac output following STEMI
B. Increased demand for oxygen in peripheral tissues
C. Overflow into venous circulation after cardiac lymphatic clearance is exceeded
D. Immediate diffusion of proteins through the coronary arteries
C
According to the criteria for acute myocardial infarction (AMI), which of the following is required for a diagnostic rise and/or fall in cardiac biomarker values?
A. At least one value above the 95th percentile of normal individuals
B. At least one value above the 99th percentile of the upper reference limit for normal individuals
C. A steady increase in values over a 24-hour period
D. Values fluctuating but remaining below the reference limit
B
What characteristic of cardiac-specific troponins T (cTnT) and I (cTnI) allows for highly specific assays to detect myocardial injury?
A. Smaller molecular weight compared to other proteins
B. Structural similarity to skeletal muscle proteins
C. Unique amino acid sequences that differ from skeletal muscle forms
D. Slow rate of release into circulation after myocardial injury
C
Why are cardiac troponins (cTnT and cTnI) considered particularly valuable in cases where there is suspicion of a small MI or skeletal muscle injury?
A. They rise more slowly than CK-MB and CK, allowing better long-term monitoring.
B. They are detectable at very low concentrations and are highly specific to cardiac tissue.
C. They are less costly to measure compared to CK-MB.
D. They decrease faster, allowing quicker return to baseline values.
B
In practical terms, high-sensitivity troponin assays are of less immediate value in which group of patients?
A. Patients with unstable angina (UA)
B. Patients with NSTEMI
C. Patients with STEMI requiring urgent reperfusion
D. Patients with skeletal muscle injury
C
Which statement is true regarding the timeline of elevation for cardiac-specific troponins (cTnT and cTnI) following STEMI?
A. They return to normal within 24 hours.
B. They remain elevated for only 2–3 days.
C. They remain elevated for 7–10 days after STEMI.
D. They are undetectable after 5 days.
C
Which laboratory marker is known to rise within 4–8 hours after STEMI and generally returns to normal within 48–72 hours?
A. cTnT
B. CK-MB
C. cTnI
D. Total CK
D
An elevated CK-MB to CK activity ratio (≥2.5) suggests which of the following?
A. Cardiac source of CK-MB elevation
B. Skeletal muscle injury only
C. Early renal failure
D. Only recent myocardial reperfusion
A
Why might hospitals prefer to use cardiac troponins (cTnT or cTnI) rather than CK-MB for diagnosing STEMI?
A. Cardiac troponins are less specific for cardiac tissue.
B. Cardiac troponins are more cost-effective and have greater sensitivity.
C. CK-MB levels remain elevated longer than cardiac troponins.
D. CK-MB levels are unaffected by extracardiac conditions
B
Which of the following biomarkers is likely to peak earlier when there is rapid reperfusion of an occluded coronary artery?
A. Erythrocyte sedimentation rate (ESR)
B. CK-MB
C. Polymorphonuclear leukocytes
D. Cardiac-specific troponins due to washout from the infarct zone
D
Which of the following best describes the initial mechanism for the release of serum cardiac biomarkers following myocardial infarction?
A. Direct diffusion through coronary arteries
B. Breakdown of the sarcolemmal membrane of cardiomyocytes
C. Immediate release from the lymphatic system
D. Passive release through capillary filtration
B
Which biomarkers are typically the first to appear in the blood following the onset of myocardial infarction?
A. Cardiac troponins T and I
B. Myoglobin and CK isoforms
C. Lactate dehydrogenase
D. Erythrocyte sedimentation rate
B
Following a large myocardial infarction, troponin levels may exceed the upper reference limit by:
A. 2–3 times
B. 10–15 times
C. 20–50 times
D. 5–7 times
C
Which of the following markers is generally less specific for myocardial injury due to its presence in skeletal muscle?
A. Myoglobin
B. CK-MB
C. Troponin I
D. Troponin T
Answer: A
A
For patients with a confirmed MI, which biomarker typically remains elevated for several days and provides a prolonged diagnostic window?
A. Myoglobin
B. Total CK
C. Troponin T
D. CK-MB
C
The nonspecific reaction to myocardial injury is associated with polymorphonuclear leukocytosis, which appears within a few hours after the onset of pain and persists for ___days;
3–7
T/F
Acute STEMI cannot be distinguished from an old myocardial scar or from acute severe ischemia by echocardiography,
T
Which of the following imaging modalities is almost universally associated with detecting wall motion abnormalities in STEMI?
A. Radionuclide ventriculography
B. Echocardiography
C. Cardiac MRI with late enhancement
D. Myocardial perfusion imaging
B
Which of the following imaging modalities is almost universally associated with detecting wall motion abnormalities in STEMI?
A. Radionuclide ventriculography
B. Echocardiography
C. Cardiac MRI with late enhancement
D. Myocardial perfusion imaging
C
Which of the following echocardiographic findings has prognostic value in STEMI by indicating the need for renin-angiotensin-aldosterone system inhibitors?
A. Detection of a ventricular aneurysm
B. Presence of mitral regurgitation
C. Reduced left ventricular (LV) function
D. Detection of a pericardial effusion
Doppler echocardiography is particularly useful in detecting which of the following serious complications of STEMI?
A. LV thrombus and RV infarction
B. Ventricular septal defect and mitral regurgitation
C. Myocardial perfusion defect and aneurysm
D. Pulmonary embolism and pericardial effusion
B
Which imaging technique is used less frequently than echocardiography in STEMI due to limitations in sensitivity and specificity?
A. Cardiac MRI
B. Radionuclide imaging
C. Doppler echocardiography
D. Coronary angiography
B
What is a limitation of myocardial perfusion imaging with [201 Tl] or [99m Tc]sestamibi in diagnosing acute myocardial infarction?
A. It cannot detect any form of perfusion defect.
B. It cannot distinguish acute infarcts from chronic scars.
C. It requires invasive administration of contrast agents.
D. It is not sensitive to changes in myocardial blood flow.
B
Radionuclide ventriculography is particularly helpful in which of the following situations?
A. Differentiating STEMI from NSTEMI
B. Assessing the hemodynamic consequences of infarction
C. Detecting pericardial effusion
D. Identifying pulmonary embolism
B
Cardiac MRI using late enhancement with gadolinium contrast is highly effective in detecting myocardial infarction because:
A. Gadolinium accumulates in the intercellular region of infarcted myocardium, creating a bright contrast against normal tissue.
B. Gadolinium specifically binds to ischemic myocytes.
C. It does not differentiate between infarcted and normal myocardium.
D. It requires no delay after contrast administration.
A
Most out-ofhospital deaths from STEMI result from the sudden development of ___
ventricular fibrillation.
The vast majority of deaths due to ventricular fibrillation occur within the ___ of the onset of symptoms, and of these, over half occur in the first hour.
first 24 h
Which of the following is a primary goal in the emergency department management of patients with suspected STEMI?
A. Avoiding the administration of aspirin
B. Ensuring rapid identification of candidates for urgent reperfusion therapy
C. Prioritizing triage to outpatient follow-up
D. Discharging patients with low-risk chest pain
B
What is the ideal timeframe for initiating PCI in a patient with STEMI from the time of first medical contact?
A. Within 30 minutes
B. Within 60 minutes
C. Within 90 minutes
D. Within 120 minutes
D
In the context of suspected STEMI, what is the initial recommended dose of aspirin to be administered in the emergency department?
A. 40–80 mg orally
B. 75–100 mg chewed
C. 160–325 mg chewed
D. 500 mg swallowed whole
C
The mechanism of action of aspirin in the management of STEMI involves inhibition of which enzyme in platelets?
A. Cyclooxygenase-1
B. Cyclooxygenase-2
C. Thromboxane synthase
D. Phospholipase A2
A
For a patient with suspected STEMI and normal arterial oxygen saturation, what is the recommended use of supplemental oxygen in the emergency department?
A. Administer oxygen continuously for the first 24 hours.
B. Oxygen is not routinely required in the absence of hypoxemia.
C. Administer oxygen only if the patient is experiencing chest pain.
D. Oxygen should be given only if the patient has low blood pressure.
B
After the initial administration of aspirin in the emergency department, what is the recommended daily dose of aspirin for ongoing management?
A. 10–50 mg orally
B. 75–162 mg orally
C. 200–400 mg orally
D. 325 mg every 6 hours
B
In the emergency department management of STEMI, which of the following statements about supplemental oxygen is correct?
A. Oxygen is only administered if the patient has chest discomfort.
B. If hypoxemia is present, administer 2–4 L/min by nasal prongs or face mask.
C. Oxygen is administered intravenously for rapid effect.
D. Oxygen administration is only required in patients with arrhythmias.
B
Which of the following statements is true regarding the role of aspirin in the emergency management of STEMI?
A. It should be delayed until after reperfusion therapy.
B. It acts by increasing thromboxane A2 levels.
C. It is effective across the entire spectrum of acute coronary syndromes.
D. It is only beneficial in patients with confirmed myocardial infarction.
C
In suspected STEMI, what is the benefit of transferring a patient from a non-PCI hospital to a PCI-capable hospital?
A. Minimizes the need for aspirin administration
B. Allows for PCI within the targeted 120-minute window from first medical contact
C. Reduces the likelihood of needing reperfusion therapy
D. Prevents the need for supplemental oxygen
B
How should sublingual nitroglycerin be administered for a patient with STEMI?
A. One dose of 0.4 mg every 10 minutes, up to three doses
B. Up to three doses of 0.4 mg at 5-minute intervals
C. One dose of 1 mg every 5 minutes, up to three doses
D. Continuous dosing until pain is completely relieved
B
In patients with STEMI, nitroglycerin helps alleviate chest discomfort by:
A. Reducing myocardial oxygen demand through preload reduction
B. Increasing myocardial oxygen supply by dilating infarct-related vessels
C. Both A and B
D. Only when administered intravenously
C
In which of the following situations should nitroglycerin be avoided in a STEMI patient?
A. Systolic blood pressure >100 mmHg
B. Suspected RV infarction
C. Prior use of beta blockers
D. Heart rate >90 beats per minute
B
Why should nitrates be avoided in STEMI patients who have taken a phosphodiesterase-5 inhibitor within the past 24 hours?
A. Risk of severe hypotension
B. Increased risk of arrhythmias
C. Potential for coronary spasm
D. Risk of myocardial infarction recurrence
A
In the management of STEMI, which of the following describes the ideal method of administering morphine for pain control?
A. A single large subcutaneous dose
B. Repetitive small intravenous doses every 5 minutes
C. Intramuscular injection every 15 minutes
D. A single large intravenous bolus
B