Valvular Heart Disease Flashcards
(36 cards)
What is Acute Rheumatic Fever?
- an inflammatory disease that can develop as a complication of untreated or inadequately treated Group A Streptococcus (GAS) pharyngitis — commonly known as strep throat.
- It mainly affects children and young adults.
- The inflammation involves the heart (especially valves), joints, skin, and central nervous system.
- It’s a post-infectious autoimmune reaction triggered by molecular mimicry — the body’s immune system attacks its own tissues because they resemble the strep bacteria.
Connection with Strep Throat
* ARF follows an infection with Group A Streptococcus (GAS) in the throat (strep throat).
* Usually, ARF appears 2-4 weeks after the strep throat infection.
* If strep throat is not properly treated with antibiotics, the risk of developing ARF increases.
* Note: Not everyone who gets strep throat develops ARF — it depends on host factors and immune response.
(elevated ASO or anti-DNase B titers is marker for prio B-hemolytic strep)
What are the symptoms of ARF?
- Fever
- Migratory polyarthritis (painful, swollen joints that move around)
- Carditis (inflammation of heart layers, especially causing valvulitis)
- Chorea (involuntary movements, Sydenham chorea)
- Erythema marginatum (a type of rash)
- Subcutaneous nodules
What is the Jones Criteria?
The Jones criteria are a set of clinical guidelines used to diagnose ARF. They require evidence of a preceding strep infection plus a combination of major and minor criteria.
- Evidence of recent Group A Streptococcus infection
At least one of:
* Positive throat culture for GAS
* Positive rapid strep antigen test
* Elevated or rising anti-streptolysin O (ASO) titer or other streptococcal antibody titers
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- Major criteria (need two major OR one major + two minor):
- Migratory polyarthritis (large joints mostly)
- Carditis (clinical or echocardiographic evidence)
- Sydenham chorea (involuntary movements)
- Erythema marginatum (pink, non-itchy rash with clear center)
- Subcutaneous nodules (firm, painless lumps over bony surfaces)
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- Minor criteria:
- Fever
- Arthralgia (joint pain without swelling)
- Elevated ESR or CRP (inflammatory markers)
- Prolonged PR interval on ECG (heart conduction delay)
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Diagnosis requires:
* Evidence of recent GAS infection plus
* Either 2 major criteria OR 1 major + 2 minor criteria
What layers of the heart does ARF impact?
- Acute rheumatic fever (ARF) is a pancarditis, meaning it affects all layers of the heart (pericardium, myocardium, and endocardium).
- While ARF can affect all layers, endocardial involvement, particularly the mitral valve, is most severe, leading to valvulitis and regurgitation.
-Pancarditis:
ARF is characterized by pancarditis, where all three layers of the heart (pericardium, myocardium, and endocardium) are affected.
- Endocardial Involvement:
The endocardium, the innermost layer of the heart, is particularly affected, leading to inflammation, or valvulitis, of the mitral valve and, less commonly, the aortic valve. - Mitral Valve:
The mitral valve is most commonly affected, leading to regurgitation. - Other Valves:
The aortic valve can also be affected, but to a lesser extent than the mitral valve. - Rheumatic Heart Disease (RHD):
RHD, which is a chronic complication of ARF, primarily affects the cardiac valves, leading to regurgitation or stenosis. - Myocardial Involvement:
Myocardial involvement can lead to heart failure, particularly in younger patients. Myocarditis is inflammation of the heart muscle, called the myocardium. The condition can reduce the heart’s ability to pump blood. Myocarditis can cause chest pain, shortness of breath, and rapid or irregular heartbeats. Infection with a virus is one cause of myocarditis.
What are the vegetation at the margin of the Mitral valve in ARF?
- Vegetations at the margin of valve (First Image)
- These vegetations are small nodules or growths made up of fibrin, platelets, and inflammatory cells.
- In the context of ARF, they represent valvulitis, or inflammation of the heart valves.
- ARF can cause rheumatic heart disease, which often involves damage to the heart valves, especially the mitral valve.
- These vegetations usually form along the lines of closure of the valves (valve margins).
- They are part of the carditis seen in ARF (one of the major Jones criteria).
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- Myocarditis with Aschoff bodies (Second Image)
- Aschoff bodies are the hallmark histological lesions of ARF.
- They are areas of chronic inflammation within the myocardium (heart muscle) consisting of:
- Reactive histiocytes with wavy nuclei (called Anitschkow cells),
- Multinucleated giant cells,
- Fibrinoid necrosis and inflammatory infiltrate.
- These lesions indicate myocarditis (inflammation of the heart muscle), which is also part of the carditis in ARF.
- Myocarditis with Aschoff bodies can lead to heart dysfunction and is a major cause of morbidity and mortality during the acute phase.
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In summary:
* ARF causes an autoimmune inflammatory reaction affecting the heart, especially the valves (valvulitis with vegetations) and the myocardium (myocarditis with Aschoff bodies).
* This cardiac involvement is part of the major Jones criteria for diagnosis.
* Untreated or recurrent ARF can cause chronic damage, leading to rheumatic heart disease.
What is the hallmark histological finding of Rheumatic Myocarditis (myocarditis due to Rheumatic Fever)?
- In the context of myocarditis due to Rheumatic Fever (ARF), the key difference lies in the type of cells and their association with the inflammatory lesions. - - Aschoff bodies are granulomatous lesions, characterized by Aschoff giant cells and other inflammatory cells, and are considered a pathognomonic sign of ARF. - - Anitschkow cells are a type of giant cell found within Aschoff bodies.
Here’s a more detailed breakdown:
- Aschoff Bodies:
These are the hallmark lesions of rheumatic heart disease. They are granulomatous in nature, consisting of a central area of fibrinoid necrosis surrounded by various inflammatory cells, including Aschoff giant cells, lymphocytes, macrophages, and plasma cells. - Aschoff bodies are primarily found in the myocardium, specifically in the endocardium, subendocardium, and perivascular regions.
- Aschoff Giant Cells (or Anitschkow Cells):
These are a type of multinucleated giant cell that are a key component of Aschoff bodies. They have a distinctive “owl’s eye” appearance and are derived from macrophages. - Anitschkow Cells:
These are another type of giant cell found in Aschoff bodies, but they are not the primary focus of this explanation. They are characterized by a “cigar-shaped” or “owl’s eye” appearance and are also derived from macrophages.
In essence, Aschoff bodies are the characteristic lesion of rheumatic heart disease, and Aschoff giant cells (Anitschkow cells) are a type of giant cell that are a prominent component of these lesions.
What happens to ARF attack once it is resolved, and we are exposed to group A B-hemolytic streptococci again?
- ARF can progress to Chronic Rheumatic Heart Disease
- there can be a relapse of the acute phase
What happens in Chronic Rheumatic Heart Disease compared to ARF?
- Acute Rheumatic Fever (ARF) is a short-term inflammatory disease that can follow a strep throat infection, affecting joints, skin, brain, and heart.
- Chronic Rheumatic Heart Disease (RHD) is the long-term, permanent damage to the heart valves caused by ARF, often due to repeated episodes or a severe initial episode.
Key Differences:
- Timeframe:
ARF is a temporary, acute illness that typically resolves within a few weeks, though the heart inflammation can persist. RHD is a chronic condition that develops after ARF and can persist for years.
- Severity:
ARF’s effects on the heart are often temporary, but RHD involves permanent damage and scarring of the heart valves, potentially leading to valve stenosis or regurgitation.
- Impact:
ARF primarily causes inflammation in various tissues, including the heart. RHD results from the cumulative scarring and damage to the heart valves caused by repeated or severe ARF episodes.
- Treatment:
ARF is treated with antibiotics and anti-inflammatory medications to manage the inflammatory response and prevent recurrence. RHD treatment focuses on managing complications such as heart failure and may involve valve replacement.
In simpler terms:
ARF is like a temporary bout of fever and inflammation after a strep infection. RHD is the permanent, long-term damage to the heart valves that can result from repeated or severe episodes of ARF.
What can happen to heart valves in Chronic Rheumatic heart disease?
- valve scarring arises as a consequence of rheumatic fever
- Almost always involves the
mitral valve; leads to thickening
of chordae tendineae and cusps - Occasionally involves the aortic
valve; leads to fusion of the
commissures - Other valves are less commonly
involved - Complications include infectious
endocarditis. - we see FUSED COMMISURES (reduced orriface, buttonhole deformity).
What is Aortic Stenosis?
- narrowing of the aortic valve orifice
- due to fibrosis and calcification from “wear and tear” as we progress through life
- presents in late adulthood (> 60 years)
- CONGENITAL Bicuspid Aortic valves increase risk of disease and can make it worse by calcification
- ACQUIRED BICUSPID aortic valve due to Chronic Rheumatic fever and fused commisure of the vlaves can lead to stenosis and insufficiency as well (fusion of all commissures)
-There is HYPERTROPHY of the LV in Aortic Stenosis
- hypertrophy and elongation of the LV puts tension on the chordae tendinae, this can prevent full closure of mitral vale
How to differentiate aortic stenosis due to wear and tear calcification or due to chronic rheumatic valve disease?
- coexistinf mitral stenosis and fusion of the aortic valve commissures are a sign of rheumatic disease
- In rheumatic disease, we will always have Mitral Stenosis along with Aortic Stenosis
** Rheumatic Dx always has Mitral involvement FIRST, followed possibly by aortic. So, aortic stenosis alone is not indicative of rheumatic dx
** Aortic valve will have fusion of the comissures in chronic rheumatic valvular dx, BUT degenerative aortic stenosis (wear and tear) has no fusion of the aortic comissures
What heart sound is in Aortic stenosis?
- compensation by the LV eventually BLOWS OPEN the aortic valve
- Systolic Ejection Click followed by a CRESENDO-DECRESCENDO murmur is heard
(blood gushes out all at once due to blown valve then slows down and gets softer)
What complications can arise from Aortic Stenosis?
- Concentric LV hypertrophy:
Aortic stenosis primarily leads to concentric left ventricular hypertrophy (LVH), not eccentric LVH. While volume overload can contribute to eccentric hypertrophy in other conditions, it’s the increased pressure against which the left ventricle must pump that’s the primary driver of LVH in aortic stenosis.
Here’s why:
Aortic Stenosis and Pressure Overload:
Aortic stenosis is a narrowing of the aortic valve, restricting blood flow out of the heart. This increased resistance against which the left ventricle must pump leads to pressure overload, causing the ventricle to thicken and become more robust.
Concentric Hypertrophy:
This thickening is primarily an increase in the thickness of the muscle wall, resulting in a concentric hypertrophy.
Eccentric Hypertrophy:
Eccentric hypertrophy, on the other hand, involves an increase in the chamber size and muscle wall thickness in response to a volume overload. While aortic stenosis can lead to some volume overload, the pressure overload is the dominant factor driving LVH.
Other Conditions and Volume Overload:
Conditions like aortic regurgitation, where the aortic valve leaks, cause a volume overload in the left ventricle, leading to eccentric hypertrophy. - angina and syncope with exercise
Syncope is caused by the decrease in cerebral perfusion occurring during exertion when the arterial pressure declines due to systemic vasodilation and an inadequate increase in cardiac output related to stenosis. It is also due to the malfunction of the baroreceptor mechanism in severe aortic stenosis. - Microangiopathic Hemolytic Anemia:
Aortic stenosis (AS), a narrowing of the aortic valve, can contribute to microangiopathic hemolytic anemia (MAHA) by creating high shear stress on red blood cells as they pass through the valve. This mechanical injury causes red blood cell fragmentation and increased hemolysis, leading to MAHA.
Elaboration:
Mechanism of MAHA:
MAHA is characterized by the destruction of red blood cells (RBCs) within the small blood vessels due to mechanical forces or abnormalities in the vessel walls. In the case of AS, the narrowed valve creates a high-pressure gradient and a turbulent blood flow, which exerts significant shear stress on passing RBCs.
Red Blood Cell Damage:
The extreme shear forces can cause RBCs to fragment into smaller pieces called schistocytes, which are indicative of MAHA. These schistocytes can further disrupt blood flow and contribute to a vicious cycle of hemolysis.
Hemolytic Anemia:
The ongoing destruction of RBCs leads to hemolytic anemia, a condition where the body’s ability to produce RBCs cannot keep up with the rate of destruction.
Treatment for Aortic Stenosis?
- valve replacement afte the onset of complications
What is Aortic Regurgitation?
- Backflow of blood from the
aorta into the left ventricle
during diastole- Most common cause: Isolated aortic root dilation
- Etiologies:
- Aortic root dilation:
- Can occur due to:
- Syphilitic aneurysm (tertiary syphilis)
- Aortic dissection
- Other connective tissue disorders (e.g., Marfan syndrome)
- Valve damage:
- Can result from:
- Infectious endocarditis
- Rheumatic fever
- Trauma
What is the Aortic Root?
The aortic root is the section of the aorta that:
* Begins at the aortic valve (the valve between the left ventricle and the aorta).
* Includes the part where the coronary arteries branch off.
* Supports the valve’s structure and helps ensure proper valve closure.
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What Happens in Aortic Root Dilation?
When the aortic root dilates:
* The aortic valve leaflets can’t close properly because they are pulled apart.
* This leads to aortic regurgitation, where blood leaks backward from the aorta into the left ventricle during diastole.
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Causes of Aortic Root Dilation:
* Hypertension (chronically elevated blood pressure)
* Connective tissue diseases (e.g., Marfan syndrome, Ehlers-Danlos syndrome)
* Syphilitic aneurysm (tertiary syphilis damaging the aortic wall)
* Aortic dissection
* Age-related degeneration
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Summary:
Root dilation = widening of the beginning of the aorta → aortic valve can’t close properly → blood leaks backward → aortic regurgitation.
What are Key Clinical Features of Aortic Regurgitation?
- Heart Murmur
- Early, blowing diastolic murmur
- Best heard at the left sternal border.
- Caused by blood flowing back from the aorta into the left ventricle during diastole.
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- Hyperdynamic Circulation
Caused by:
* Increased stroke volume (left ventricle compensates by pumping more blood).
* Wide pulse pressure (large difference between systolic and diastolic pressures).
Key findings:
* Bounding pulse (Water-hammer pulse)
* A strong, rapidly rising and collapsing pulse.
* Pulsating nail bed (Quincke’s pulse)
* Capillary pulsations visible in the nail beds.
* Head bobbing (de Musset’s sign)
* Head bobs with each heartbeat due to forceful pulse.
What is treatment of Aortic Regurgitation?
LV dilation and eccentric
hypertrophy
* Treatment is valve replacement
once LV dysfunction develops
- stenosis leads to concentric hypertrophy due to increase pressure
What is a Mitral Valve Prolapse?
Definition:
* Ballooning of the mitral valve into the left atrium during systole.
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Cause:
* Myxoid degeneration of the valve:
* The connective tissue becomes weakened and floppy.
* This is the most common cause.
* Associated conditions:
* Marfan syndrome
* Ehlers-Danlos syndrome
* Often idiopathic (no known cause in many cases).
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Clinical Features:
* Auscultation:
* Mid-systolic click (classic finding)
* Followed by a regurgitation murmur
* Maneuver effects:
* Click and murmur become louder with squatting.
* Squatting increases venous return → increases left ventricular volume → delays prolapse → murmur moves later and becomes louder.
* Usually asymptomatic, but may rarely cause:
* Palpitations
* Chest pain
* Rarely, complications like infective endocarditis, arrhythmias, or mitral regurgitation.
Effect of Respiration and squatting on Left-Sided Murmurs (Including MVP)?
- Expiration increases venous return to the left side of the heart.
- Inspiration increases venous return to the right side of the heart.
For Mitral Valve Prolapse (MVP):
* During expiration:
* More blood returns to the left atrium and left ventricle.
* The increased left ventricular volume delays the prolapse of the valve because the larger ventricle holds the mitral valve in place longer.
* This delays the click and murmur and often softens them (opposite of what you might intuitively expect).
* During inspiration:
* Less blood in the left ventricle → the valve prolapses earlier → the click and murmur occur earlier and are louder.
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Key Maneuvers:
* Squatting: Increases venous return → larger left ventricle → prolapse occurs later → murmur gets softer and click moves later.
* Standing or Valsalva: Decreases venous return → smaller left ventricle → prolapse occurs earlier → murmur gets louder and click moves earlier.
Final Answer:
Expiration does not make MVP worse.
It actually tends to delay and soften the murmur because the left ventricle is filled more, holding the valve in place longer.
Core Concept: Mitral Valve Prolapse (MVP) Murmur Timing Depends on Left Ventricular Volume
* Small LV volume → earlier prolapse → earlier click → louder murmur.
* Large LV volume → delayed prolapse → later click → softer murmur.
Squatting Does Both:
* Increases venous return → increases LV volume → delays prolapse → click happens later.
* Increases systemic vascular resistance → potentially increases murmur loudness.
However, in MVP, the dominant effect is the volume change.
* Because the prolapse happens later, the murmur is usually softer despite the increased afterload.
* In fact, in MVP, maneuvers that decrease LV volume (like standing) typically produce louder murmurs because the prolapse is more abrupt and regurgitation is more pronounced.
👉 For MVP: Volume effects > Afterload effects.
What is Mitral Regurgitation?
What is it?
* Functional problem: The mitral valve fails to close properly, allowing blood to leak backward from the left ventricle into the left atrium during systole.
Causes:
* Mitral valve prolapse (can lead to MR)
* Rheumatic heart disease
* Infective endocarditis
* Papillary muscle rupture (post-MI)
* Annular dilation (from heart failure)
Key Features:
* Murmur: Holosystolic (pansystolic) murmur best heard at the apex, often radiating to the axilla.
* Can cause symptoms of heart failure (fatigue, dyspnea, pulmonary edema).
* Often associated with left atrial and left ventricular enlargement.
🚨 Big Picture:
* All MVP can cause MR, but not all MR is due to MVP.
* MVP is a specific type of valve abnormality.
* MR is the actual hemodynamic problem of blood leaking backward.
What are causes of Mitral Regurgitation?
🔹 Causes of Mitral Regurgitation (MR)
- Mitral Valve Prolapse (MVP)
- Most common cause in developed countries.
- Myxoid degeneration → floppy valve → prolapse → possible regurgitation.
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- Left Ventricular (LV) Dilatation
- Example: Left-sided heart failure or dilated cardiomyopathy.
- LV enlargement stretches the mitral valve annulus → prevents proper closure → functional regurgitation.
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- Infective Endocarditis
- Infection damages the valve leaflets → leads to poor coaptation → regurgitation.
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- Acute Rheumatic Heart Disease
- Inflammatory process causes transient regurgitation (can later lead to mitral stenosis if chronic).
- Typically follows untreated Group A Streptococcal pharyngitis.
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- Papillary Muscle Rupture (Post-Myocardial Infarction)
- Usually occurs after an inferior MI (right coronary artery supplies the posteromedial papillary muscle, which has a single blood supply).
- Papillary muscle rupture → valve loses its support → acute, severe mitral regurgitation → life-threatening.
Holosystolic “blowing” murmur
* Louder with squatting and
expiration
* Results in volume overload and
left-sided heart failure
What is Mitral Stenosis?
- Narrowing of the mitral valve
orifice - Usually due to chronic rheumatic
valve disease - Opening snap followed by
diastolic rumble
Volume overload leads to dilation of the Left Atrium which can cause:
- pulmonary congestion
- pulmonary hypertension
- Atrial Fibrillation
🌟 Core Concept:
Mitral stenosis (MS) leads to left atrial dilation → this structural change predisposes to atrial fibrillation (AF), even though the SA node is in the right atrium.
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Step-by-Step Explanation:
- Mitral Stenosis: Obstruction to Left Ventricular Filling
- The narrowed mitral valve makes it hard for blood to flow from the left atrium to the left ventricle.
- As a result, left atrial pressure increases.
- Over time, this leads to left atrial enlargement.
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- Left Atrial Enlargement → Electrical Instability
- The enlarged left atrium stretches the atrial myocardium.
- Stretching:
- Disrupts normal conduction pathways.
- Creates areas of fibrosis and reentrant circuits.
- These changes make it easier for abnormal electrical impulses to develop and sustain atrial fibrillation.
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- Why Doesn’t the SA Node Location Prevent AF?
- The SA node is the pacemaker located in the right atrium, but:
- Atrial fibrillation is not a problem of the SA node.
- AF is a problem of chaotic, rapid electrical signals originating in the atrial walls, especially around the pulmonary veins in the left atrium.
- Once the left atrium becomes large and electrically unstable, those rapid, disorganized signals can override the SA node’s pacemaking function.
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🔍 Key Point:
* The size, pressure, and conduction properties of the atrial tissue determine susceptibility to AF, not the SA node’s location.
* The left atrium plays a major role in the development of AF.
What is Endocarditis?
- Inflammation of endocardium
that lines the surface of cardiac
valves
- Inflammation of endocardium
- Usually due to bacterial infection
Endocarditis is an infection (usually bacterial) of the endocardium, which is the inner lining of the heart chambers and heart valves.
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Key Points:
- Affected Structures
- Most often affects the heart valves (native or prosthetic).
- Can also involve congenital heart defects or areas of damaged endocardium.
- Types
- Infective Endocarditis (IE): caused by bacteria or fungi.
- Non-infective (sterile) endocarditis: such as Libman-Sacks endocarditis in lupus.
- Pathogenesis
- Damage to endocardium or valves → allows microbes to stick.
- Formation of vegetations (masses of platelets, fibrin, microorganisms).
- These vegetations can damage the valves, cause emboli, or trigger immune responses.
- Common Causes (Microorganisms)
- Staphylococcus aureus (especially in IV drug users and prosthetic valves)
- Streptococcus viridans (often in people with pre-existing valve disease)
- Enterococci
- Fungi (less common)
- Clinical Features
- Fever, chills, night sweats.
- New or changing heart murmur.
- Signs of embolism (stroke, infarcts).
- Immune phenomena (glomerulonephritis, Osler nodes).
- Diagnosis
- Blood cultures (to identify organism).
- Echocardiogram (to visualize vegetations).
- Duke criteria (clinical and lab criteria for diagnosis).
Describe Streptoccocus Viridans:
- Most common overall cause
- Low-virulence organism that
infects previously damaged
valves - Results in small vegetations that
do not destroy the valve
Damaged endocardial surface
develops thrombotic vegetations
(platelets and fibrin) - Transient bacteremia leads to
trapping of bacteria in the
vegetations
