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Questions and Answers
What is a primary feature of dilated cardiomyopathy?
What is a primary feature of dilated cardiomyopathy?
Which condition is most likely to result in outflow obstruction for the left ventricle?
Which condition is most likely to result in outflow obstruction for the left ventricle?
Which of the following factors contributes to plaque instability in atherosclerosis?
Which of the following factors contributes to plaque instability in atherosclerosis?
What is the estimated prevalence of hypertrophic cardiomyopathy (HOCM) in the general population?
What is the estimated prevalence of hypertrophic cardiomyopathy (HOCM) in the general population?
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Which statement about restrictive cardiomyopathy is accurate?
Which statement about restrictive cardiomyopathy is accurate?
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What is the primary consequence of increased deposition of oxidized LDL in the context of atherosclerosis?
What is the primary consequence of increased deposition of oxidized LDL in the context of atherosclerosis?
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Which risk factor is associated with increased endothelial damage and a subsequent rise in oxidative stress?
Which risk factor is associated with increased endothelial damage and a subsequent rise in oxidative stress?
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What role does Lp(a) play in the development of atherosclerosis?
What role does Lp(a) play in the development of atherosclerosis?
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What effect do AGEs have in the context of diabetes and atherosclerosis?
What effect do AGEs have in the context of diabetes and atherosclerosis?
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How does Lp(a) structurally resemble LDL?
How does Lp(a) structurally resemble LDL?
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What is a significant genetic factor related to Lp(a) levels?
What is a significant genetic factor related to Lp(a) levels?
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Which of the following statements is true regarding high levels of Lp(a)?
Which of the following statements is true regarding high levels of Lp(a)?
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What is a primary origin of Lp(a) in the human body?
What is a primary origin of Lp(a) in the human body?
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What primarily distinguishes eroded plaques from ruptured plaques?
What primarily distinguishes eroded plaques from ruptured plaques?
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Which component of metabolic syndrome is directly associated with the production of advanced glycation end-products (AGEs)?
Which component of metabolic syndrome is directly associated with the production of advanced glycation end-products (AGEs)?
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What role do neutrophil extracellular traps (NETs) play in plaque erosion?
What role do neutrophil extracellular traps (NETs) play in plaque erosion?
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How does the presence of advanced glycation end-products (AGEs) affect LDL within the vascular system?
How does the presence of advanced glycation end-products (AGEs) affect LDL within the vascular system?
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What is one significant effect of visceral obesity in the context of metabolic syndrome?
What is one significant effect of visceral obesity in the context of metabolic syndrome?
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Which of the following factors is primarily associated with increasing Lp(a) secretion?
Which of the following factors is primarily associated with increasing Lp(a) secretion?
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What is one proposed mechanism by which Lp(a) contributes to atherogenesis?
What is one proposed mechanism by which Lp(a) contributes to atherogenesis?
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What characterizes an unstable plaque?
What characterizes an unstable plaque?
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How does inflammation affect the stability of atherosclerotic plaques?
How does inflammation affect the stability of atherosclerotic plaques?
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What potential effect do activated platelets have on plaque stability?
What potential effect do activated platelets have on plaque stability?
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Which of the following is NOT a proposed effect of Lp(a) in cardiovascular risk?
Which of the following is NOT a proposed effect of Lp(a) in cardiovascular risk?
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What component is thought to be responsible for many adverse effects of Lp(a)?
What component is thought to be responsible for many adverse effects of Lp(a)?
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Which of the following statements about unstable plaques is accurate?
Which of the following statements about unstable plaques is accurate?
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Which of the following conditions is most closely associated with heart failure with preserved ejection fraction (HFpEF)?
Which of the following conditions is most closely associated with heart failure with preserved ejection fraction (HFpEF)?
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What is a common characteristic of dilated cardiomyopathy as opposed to hypertrophic cardiomyopathy?
What is a common characteristic of dilated cardiomyopathy as opposed to hypertrophic cardiomyopathy?
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Which of the following is NOT typically a cause of dilated cardiomyopathy?
Which of the following is NOT typically a cause of dilated cardiomyopathy?
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Among the following, which symptom is primarily associated with hypertrophic cardiomyopathy?
Among the following, which symptom is primarily associated with hypertrophic cardiomyopathy?
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What is a characteristic feature of restrictive cardiomyopathy?
What is a characteristic feature of restrictive cardiomyopathy?
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What is the most common genetic cause of dilated cardiomyopathy?
What is the most common genetic cause of dilated cardiomyopathy?
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Which pathogenesis mechanism is associated with restrictive cardiomyopathy?
Which pathogenesis mechanism is associated with restrictive cardiomyopathy?
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Which of these conditions can lead to dysrhythmias in dilated cardiomyopathy?
Which of these conditions can lead to dysrhythmias in dilated cardiomyopathy?
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Which of the following features is indicative of hypertrophic cardiomyopathy?
Which of the following features is indicative of hypertrophic cardiomyopathy?
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What is a common clinical manifestation of dilated cardiomyopathy?
What is a common clinical manifestation of dilated cardiomyopathy?
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Which condition is associated with a high rate of mortality and disability primarily due to heart failure?
Which condition is associated with a high rate of mortality and disability primarily due to heart failure?
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Which of the following is NOT a typical effect of heart failure in dilated cardiomyopathy?
Which of the following is NOT a typical effect of heart failure in dilated cardiomyopathy?
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Which of the following best describes a primary cause of atherosclerosis?
Which of the following best describes a primary cause of atherosclerosis?
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Study Notes
BMS 200 - Week 6 Cardiology E-learning
- Cardiomyopathies and Atherosclerosis Pathogenesis were covered in this e-learning session.
- The e-learning noted the following outcomes related to cardiomyopathies:
- Describe the epidemiology, pathogenesis, clinical features, and prognosis of Hypertrophic cardiomyopathy, Dilated cardiomyopathy (hereditary), and Restrictive cardiomyopathy.
- Define the pathogenesis of atherosclerosis and the generation of unstable plaques, particularly focusing on Lipoprotein A (Lp(a)) biology, Metabolic syndrome, and factors contributing to plaque instability.
Cardiomyopathies
- Cardiomyopathies are disorders targeting cardiac myocytes or extracellular tissue in the myocardium.
- Major types include:
- Dilated Cardiomyopathies:
- Genetic deficits in sarcomere proteins (often autosomal dominant).
- Acquired types usually involve infectious, inflammatory, or toxic factors.
- Hypertrophic Cardiomyopathy:
- Genetic deficits in sarcomere proteins.
- Restrictive Cardiomyopathy:
- A range of causes associated with abnormal extracellular material deposition.
- Dilated Cardiomyopathies:
Hypertrophic Cardiomyopathy
- Often abbreviated as HOCM, with "O" standing for "obstructive".
- Characterized by a thickened septum (wall separating ventricles).
- Frequently leads to outflow obstruction from the left ventricle, affecting the aorta's entry.
- One of the common autosomal dominant disorders (prevalence around 1 in 500), with varying severity across patients.
- General pathogenesis:
- Mutations within sarcomere proteins (like myosin) often lead to a gain-of-function.
- The exact mechanism leading to hypertrophy isn't fully understood.
- Myocytes show disorganization in orientation.
Hypertrophic Cardiomyopathy - Clinical Features
- Many cases are asymptomatic, making diagnosis challenging.
- A significant cause of sudden cardiac death or arrest, especially in athletes, due to potentially dangerous dysrhythmias.
- Symptoms like angina, dyspnea, and syncope tend to become more prominent with age.
- Syncope relates to the sudden loss of consciousness due to globally impaired cerebral hypoperfusion.
- Heart failure with preserved ejection fraction (HFpEF) can develop over time in some cases, and a subgroup may transition to HFrEF later.
Dilated Cardiomyopathy
- Often the most common type of cardiomyopathy.
- Causes are diverse, including:
- Toxin exposure (e.g., alcohol, certain medications, stressful events).
- Cancer treatments.
- Peripartum events (during pregnancy or shortly after).
- Genetic mutations (often autosomal, sometimes X-linked).
- Inflammatory conditions (e.g., infection, sarcoidosis).
- Characterized by:
- A massive heart despite a seemingly thin wall.
- Typically affects the ventricles more severely than the atria.
- Flabbiness of the heart walls.
- Increased risk of regurgitation of AV (atrioventricular) valves.
- A usual echocardiogram finding of HFrEF.
- Microstructure variations (hypertrophy and atrophy/fibrosis in myocardial sections) visible in microscopy.
Dilated Cardiomyopathy - Clinical Features
- Patients can be asymptomatic until heart failure symptoms emerge.
- Typical heart failure signs include fatigue, intolerance to exercise, shortness of breath (dyspnea), and swelling in dependent areas (dependent edema).
- Great ventricular enlargement can cause mitral valve regurgitation.
- Palpitations or syncope are possible due to dysrhythmias.
- Many acquired causes show improvement if the initial injury is resolved, but significant damage may necessitate a heart transplant.
Restrictive Cardiomyopathy
- The least common cardiomyopathy type discussed.
- Characterized by restricted ventricular filling and reduced diastolic volume in at least one (sometimes both) ventricles, while systolic function and wall thickness remain normal or nearly normal.
- High mortality rate usually due to heart failure, and the condition doesn't resolve independently.
- Patients typically exhibit isolated diastolic dysfunction (HFpEF) with normal stroke volume.
- Pathogenesis can be related to conditions "outside the heart":
- Amyloidosis.
- Conditions like hemochromatosis or sarcoidosis that negatively impact heart function.
- More discussion on these causes in future courses.
Atherosclerosis - Pathogenic Mechanisms
- A multifaceted disorder varying across individuals due to environmental and genetic influences.
- Key factors include:
- Systemic and local inflammation.
- Dyslipidemia (especially elevated lipoprotein A (Lp(a))).
- Metabolic syndrome and diabetes.
- Hypertension.
Atherosclerosis - Review
- Starts with fatty streaks and progresses through oxidized LDL deposition, macrophage migration/activation, and calcification.
- Foam cell development results from cholesterol accumulation.
- Accumulation of extracellular matrix within the intima leads to a variably-stable fibrous cap over necrotic tissue and immune cells.
- The lumen narrows (stenosis) impairing blood flow.
Review - Risk Factors and Atherosclerosis Development
- Smoking, high blood pressure, and oxidative stress increase endothelial damage.
- Elevated Lp(a) likely contributes to increasing endothelial damage by improving immune cell recruitment at the plaque.
- Diabetes and dyslipidemia (including metabolic syndrome) potentially make LDL more likely to be incorporated into the intima (particularly when considering age-related changes and oxidation).
- Age-related modifications may increase overall inflammation contributing to oxidative stress.
More on Lp(a)
- Everyone has some Lp(a).
- The liver produces Lp(a), and production can increase with acute phase responses (triggered by cytokines like IL-6).
- Women generally produce more Lp(a) than men, although higher levels are linked with a greater risk for cardiovascular events.
- Similar structure to LDL but important differences are highlighted in structural diagrams.
- Lp(a) binds oxidized phospholipids, and this is thought to be central to its pathogenic role.
More on Lp(a) (cont)
- Lp(a) can contribute to atherosclerosis by initiating coagulation, increasing unstable plaque development, activating monocytes in the arterial wall, and promoting pro-inflammatory cytokine/adhesion molecule expression.
- Elevated IL-6 levels are linked with increased Lp(a) and seem to contribute most to atherogenic effects.
More on Plaque Types
- Unstable plaques have vulnerable fibrous caps, susceptible to rupture and release of thrombogenic molecules, thereby increasing cardiovascular risk.
- Factors affecting plaque stability include the quantity of collagen in the fibrous cap
- Activated platelets support collagen production and deposition, although the initial trigger for activation may have involved endothelial cell damage.
- Activated macrophages contribute by producing metalloproteinases, which degrade collagen and decrease plaque stability.
Unstable Plaques and ACS
- Harrison's video is a valuable resource regarding unstable plaques and acute coronary syndromes.
- The Atlas of Atherosclerosis from Harrison's Principles of Internal Medicine provides a more detailed description.
- The chapter highlights unstable plaques and acute coronary events (ACS).
More on Plaque Types - FYI
- Plaque erosion is a separate pathophysiological pathway from plaque rupture and can also lead to ACS.
- Eroded plaques have a more stable fibrous cap and overlying thrombus, with a different inflammatory profile than ruptured plaques.
- In eroded plaques, neutrophils are major contributors to creating a complex matrix (NET).
- Although plaque erosion contributes significantly to ACS, it's less well-understood than rupture.
Diabetes and the Metabolic Syndrome
- Conditions related to the metabolic syndrome influence atherosclerosis development
- Elevated VLDL is linked with increased circulating LDL, which fuels atherogenesis.
- Increased visceral fat is associated with insulin resistance, increased free fatty acids (FFAs), and increased pro-inflammatory cytokines production.
- AGEs accumulate in the basement membrane, including the tunica intima
- AGEs on LDL increase the likelihood of pro-inflammatory cell activation and foam cell development.
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Description
This e-learning session covers critical aspects of cardiomyopathies and atherosclerosis pathogenesis. Students will learn about the epidemiology, pathogenesis, clinical features, and prognosis of various types of cardiomyopathies, alongside the underlying mechanisms of atherosclerosis and plaque instability. Prepare to explore these vital topics in cardiovascular health.
