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Questions and Answers
What occurs when the oxygen demand exceeds the oxygen supply in the heart muscle?
What occurs when the oxygen demand exceeds the oxygen supply in the heart muscle?
Which statement accurately describes stable angina pectoris?
Which statement accurately describes stable angina pectoris?
What characterizes unstable angina pectoris?
What characterizes unstable angina pectoris?
What is a main distinguishing feature of transmural myocardial infarction?
What is a main distinguishing feature of transmural myocardial infarction?
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Which of the following describes the pain typically associated with unstable angina?
Which of the following describes the pain typically associated with unstable angina?
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What occurs within the first 10 seconds of myocardial infarction?
What occurs within the first 10 seconds of myocardial infarction?
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What is a consequence of decreased oxygen availability in myocardial cells?
What is a consequence of decreased oxygen availability in myocardial cells?
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What happens to myocardial cells after 20 minutes without oxygen?
What happens to myocardial cells after 20 minutes without oxygen?
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Which of the following is NOT a consequence of hypoxic injury in myocardial cells?
Which of the following is NOT a consequence of hypoxic injury in myocardial cells?
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What role do neutrophils play in myocardial cell injury during inflammation?
What role do neutrophils play in myocardial cell injury during inflammation?
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What is the primary cause of myocardial ischemia?
What is the primary cause of myocardial ischemia?
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Which condition can lead to increased myocardial demand or workload?
Which condition can lead to increased myocardial demand or workload?
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What is a common risk factor for coronary artery disease?
What is a common risk factor for coronary artery disease?
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What effect does atherosclerotic plaque have on coronary arteries?
What effect does atherosclerotic plaque have on coronary arteries?
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Which of the following is NOT a direct cause of myocardial ischemia?
Which of the following is NOT a direct cause of myocardial ischemia?
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What role does hypoxemia play in myocardial ischemia?
What role does hypoxemia play in myocardial ischemia?
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Which mediator is involved in coronary vasospasm during atherosclerosis?
Which mediator is involved in coronary vasospasm during atherosclerosis?
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What symptom is likely to be associated with transient ischemia from vasospasm?
What symptom is likely to be associated with transient ischemia from vasospasm?
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Which type of myocardial infarction is considered related to acute athero-thrombosis?
Which type of myocardial infarction is considered related to acute athero-thrombosis?
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What characterizes NSTEMI compared to STEMI?
What characterizes NSTEMI compared to STEMI?
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Which conditions can precipitate an increase in metabolic demand leading to myocardial infarction?
Which conditions can precipitate an increase in metabolic demand leading to myocardial infarction?
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Which of the following is a type of myocardial infarction associated with bypass surgery?
Which of the following is a type of myocardial infarction associated with bypass surgery?
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Coronary artery emboli can lead to which type of myocardial infarction?
Coronary artery emboli can lead to which type of myocardial infarction?
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What common factor would reduce the oxygen content of blood and potentially lead to myocardial infarction?
What common factor would reduce the oxygen content of blood and potentially lead to myocardial infarction?
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Which of the following mechanisms does NOT contribute to myocardial infarction due to atherosclerosis?
Which of the following mechanisms does NOT contribute to myocardial infarction due to atherosclerosis?
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Which class of myocardial infarction is characterized by cardiac death with suggested ischemia before abnormal troponin levels are available?
Which class of myocardial infarction is characterized by cardiac death with suggested ischemia before abnormal troponin levels are available?
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What is a potential consequence of the restoration of blood flow to ischemic tissue?
What is a potential consequence of the restoration of blood flow to ischemic tissue?
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Which of the following is NOT a consequence of oxidative stress during reperfusion injury?
Which of the following is NOT a consequence of oxidative stress during reperfusion injury?
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What role do neutrophils play in reperfusion injury?
What role do neutrophils play in reperfusion injury?
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When do troponin levels start to rise after an acute myocardial infarction?
When do troponin levels start to rise after an acute myocardial infarction?
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Which cardiac biomarker is specific to cardiac muscle?
Which cardiac biomarker is specific to cardiac muscle?
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How long do elevated troponin levels remain detectable after an infarct?
How long do elevated troponin levels remain detectable after an infarct?
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What is the primary isoenzyme found in cardiac muscle that is measured during cardiac events?
What is the primary isoenzyme found in cardiac muscle that is measured during cardiac events?
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Which factor is NOT involved in the inflammatory cascade during reperfusion injury?
Which factor is NOT involved in the inflammatory cascade during reperfusion injury?
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What CK-MB to CK ratio should raise suspicion for AMI?
What CK-MB to CK ratio should raise suspicion for AMI?
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How long after an AMI do CK-MB levels begin to rise?
How long after an AMI do CK-MB levels begin to rise?
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Which cardiac biomarker is released when muscle cells are injured or die?
Which cardiac biomarker is released when muscle cells are injured or die?
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What does an elevation of C-reactive protein (CRP) indicate?
What does an elevation of C-reactive protein (CRP) indicate?
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Which LDH isoenzyme is primarily found in cardiac muscle cells?
Which LDH isoenzyme is primarily found in cardiac muscle cells?
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What is the specificity rate of lactate dehydrogenase (LDH) for diagnosing AMI?
What is the specificity rate of lactate dehydrogenase (LDH) for diagnosing AMI?
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Which CRP level indicates a high risk of cardiovascular disease?
Which CRP level indicates a high risk of cardiovascular disease?
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What is the role of myoglobin in the context of AMI?
What is the role of myoglobin in the context of AMI?
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Study Notes
Alterations of CV Function II
- This lecture covers myocardial ischemia and myocardial infarction.
- Learning objectives include explaining the pathophysiology, analyzing the relationship between cardiovascular physiology and development, differentiating causes, and predicting clinical manifestations based on pathophysiology.
Myocardial Ischemia
- Overview: Partial blockage of one or more branches of the left or right coronary artery.
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Causes:
- Coronary atherosclerosis (CAD): The leading cause, involves plaque buildup in coronary arteries, narrowing the vessel. Risk factors include smoking, diabetes mellitus, and dyslipidemia.
- Vasospasm: Vasoconstrictive mediators released during atherosclerosis may cause temporary spasms in coronary arteries, inducing transient ischemia.
- Hypoxemia: Often from pulmonary disease, reducing oxygen delivery to the myocardium.
- Anemia: Reduced oxygen carrying capacity in blood.
- Increased Myocardial Demand/Workload: Tachycardia or increased cardiac output can surpass the oxygen supply to the myocardium.
Myocardial Infarction (MI)
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Types:
- Transmural: Necrosis extends through the entire myocardium wall.
- Non-transmural: Necrosis is limited to the endocardium or subendocardium.
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Causes:
- Coronary Atherosclerosis: Primary cause, plaque buildup or rupture.
- Coronary Artery Emboli: Blood clot or other material traveling to and blocking the coronary artery.
- Aortic Dissection: Tear in the aorta that affects the coronary arteries.
- Coronary Vasospasm: Temporary constriction of the coronary arteries.
- Coronary Artery Trauma: Direct damage to the coronary artery.
- Cocaine and Other Illicit Drug Use: These drugs can trigger coronary artery spasms.
- Rx & OTC Drugs: Certain medications.
- Precipitating Conditions: Conditions that increase metabolic demand, like extreme physical exertion, hypertension, and aortic stenosis.
- Reduced Oxygenation: Hypoxemia or anemia.
Pathophysiology
- Myocardial Ischemia: Plaque buildup in coronary arteries limits blood flow, leading to reduced oxygen and nutrient delivery to the heart muscle.
- Myocardial Infarction: Impaired blood supply causes cell death. A thrombus (blood clot) forms on the plaque, blocking blood flow.
- Hypoxia & ATP: Lack of oxygen prevents the cells from producing enough ATP, further injuring the tissue.
- Ischemic Pain: Ranges from stable angina (predictable pain) to unstable angina (sudden, unpredictable pain that signals an impending MI).
- Reperfusion Injury: When blood flow resumes, the influx of oxygen may cause oxidative stress and further damage the heart muscle.
- Inflammation: Following injury, neutrophils release inflammatory mediators and reactive oxygen species that damage the cells.
- Repair and Resolution: The body's repair mechanisms attempt to heal the damaged tissue, but permanent damage is frequent.
Clinical Consequences
- Decreased ventricular pumping: Reduced contractility leads to reduced cardiac output.
- Conduction disturbances: Problems with electrical activity can affect heart rhythm and function.
- Ischemic pain: Pain, tightness, or pressure in the chest, and sometimes radiating to the arm, neck, or jaw.
Cardiac Biomarkers
- Troponin I & T: Cardiac-specific proteins released into the blood following cell damage, useful in diagnosing MI.
- CK-MB: A heart enzyme that increases in the blood after a heart attack.
- Myoglobin: Released rapidly from damaged muscle cells.
- C-reactive protein (CRP): Indicates inflammation, potentially signifying risk of heart failure and mortality after AMI.
- Lactate dehydrogenase (LDH): Enzyme released from damaged cells, used in the diagnosis of AMI (sensitivity is high, but specificity is low).
Other Labs
- Glucose: Important for evaluating metabolic health.
- Complete Blood Count (CBC): Identifies blood cell counts that can be affected by the injury.
- Chemistry Profile: Checks various blood chemistries.
- Lipid Profile: Useful for evaluating risk factors and cardiovascular health.
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Description
This quiz delves into crucial aspects of myocardial ischemia and infarction, exploring their pathophysiology and clinical implications. Participants will analyze causes, including coronary atherosclerosis and vasospasm, and predict manifestations based on underlying mechanisms.
