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What is the difference between UA and NSTEMI in Acute Coronary Syndrome?
Describe the chest pain characteristics associated with angina.
central/substernal compression or crushing chest pain, often starting in the retrosternal area and radiating to arms, neck, or jaw
Match the following terms related to Acute Coronary Syndromes with their definitions:
Myocardial infarction = Damage or death of an area of the heart muscle due to blocked blood supply Coronary Thrombosis = Formation of a clot in arteries that supply blood to the heart muscle Coronary Occlusion = Obstruction of a coronary artery leading to reduced blood flow to the heart muscle Ischemia = Local anemia due to mechanical obstruction of blood supply, often causing pain and organ dysfunction Hypoxia = Decrease in O2 levels in inspired gases, arterial blood, or tissue
______ refers to the decrease below normal levels of O2 in inspired gases, arterial blood, or tissue.
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What is the first manifestation of acute coronary occlusion?
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Which ECG change is indicative of a fully occluded vessel and myocardial injury extending through the full thickness of the heart muscle?
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Which cardiac biomarker is preferred for diagnosing myocardial infarction due to its sensitivity and duration in the bloodstream?
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When should a 12-lead ECG be obtained for a patient presenting with symptoms of acute coronary syndrome (ACS)?
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What change in the ST segment indicates NSTE-ACS?
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Which of the following ECG findings indicate acute cardiac ischemia?
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Which condition is characterized by new onset severe angina or previously diagnosed angina that has become more frequent and longer in duration?
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If cardiac biomarkers are positive, what is the likely diagnosis for a patient with acute coronary syndrome?
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Study Notes
Acute Coronary Syndromes (ACS)
- Myocardial infarction is a heart attack that results from a blocked blood supply to the heart muscle, causing damage or death of the affected area.
- Coronary thrombosis is the formation of a clot in one of the arteries that conduct blood to the heart muscle.
- Coronary occlusion is the obstruction of a coronary artery that hinders blood flow to some part of the heart muscle.
- Hypoxia is a decrease in oxygen levels in inspired gases, arterial blood, or tissue.
- Ischemia is a local anemia due to mechanical obstruction of the blood supply, often marked by pain and organ dysfunction.
Acute Coronary Syndrome - Main Characteristics
- Describes patients with a sudden imbalance between myocardial oxygen consumption and demand.
- Usually acute ischemia and/or infarction due to an abrupt reduction in coronary blood flow.
- This reduction in blood flow is usually due to coronary plaque progression or instability with or without luminal thrombosis.
Diagnosis of Acute Coronary Syndrome
- Diagnosis is determined by symptomatic presentation, ECG changes, and detection of myocardial markers.
- ECG changes indicate injury or necrosis, with ST segment changes indicating injury or necrosis, and T wave inversions indicating ischemia in the absence of myocardial infarction.
- Detection of myocardial markers indicates myocardial necrosis.
Types of Acute Coronary Syndrome
- Unstable Angina (UA): Ischemia without permanent damage, indicated by cardiac markers and ECG changes, and is characterized by accelerating anginal symptoms.
- Non-ST Elevation Myocardial Infarction (NSTEMI): Ischemia due to partial occlusion, but no myocardial injury biomarker, indicated by positive cardiac enzymes and ECG changes.
- ST Elevation Myocardial Infarction (STEMI): Ischemia due to complex occlusion, with myocardial necrosis, indicated by positive cardiac enzymes and ECG changes.
Clinical Presentation
- Chest Pain (Angina): central/substernal compression or crushing chest pain, pressure, tightness, heaviness, cramping, burning, or aching sensation, usually lasting at least 10 minutes.
- Chest pain is usually accompanied by severe dyspnea, diaphoresis, nausea/vomiting, and syncope/presyncope.
Stable vs. ACS Angina
- Stable Angina: predictable with activity, predictable in quality.
- ACS Angina: accelerating symptoms.
New Onset Severe Angina
- Characterized by increasing angina frequency and duration in previously diagnosed angina patients
ECG Interpretation
- 12-lead ECG should be obtained within 10 minutes of ED arrival
- ST segment changes indicate acute cardiac ischemia
- ST segment changes (≥ 0.05 mV) or T-wave inversion in 2 or more contiguous leads are diagnostic criteria
- ECG provides information on infarct location and size
- Areas of infarction do not produce electrical activity
- T-wave changes are the first manifestation of acute coronary occlusion (ischemia)
- T-wave inversion occurs first, followed by ST segment changes
- ST segment depression indicates lengthening of repolarization (NSTE-ACS), suggesting non-fully occluded vessels
- ST segment elevation indicates injury from ischemia extending from subendocardial to subepicardial regions (transmural ischemia), suggesting fully occluded vessels and STEMI
Laboratory Tests
- Cardiac troponin is the preferred biomarker for cardiac injury
- Troponin levels do not rise until 6 hours post-MI
- Elevated troponin levels can last up to 10-14 days
- Creatine Kinase MB fraction (CK-MB) and myoglobin are less sensitive and not recommended for myocardial infarction diagnosis
- B-type natriuretic peptide (BNP) can be added to the diagnostic panel
Diagnosis
- No cardiac biomarkers: Unstable Angina
- Positive cardiac biomarkers: NSTEMI
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Description
Learn about the different types of Acute Coronary Syndromes, including myocardial infarction, coronary thrombosis, coronary occlusion, and hypoxia.
