Valvular Heart Disease Overview

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Questions and Answers

Which gender is more frequently affected by the condition described?

Women (correct)

Neither

Men

Both equally

Which of the following is a characteristic morphological feature of the condition?

Enlargement and redundancy of mitral leaflets (correct)

Intact tendinous cords

Thinning of the muscular layer

Normal valve appearance

What is a common clinical feature of the condition discussed?

Persistent hypertension

Cyanosis

Midsystolic click (correct)

Severe chest pain

What type of endocarditis is characterized by microbial infection of heart valves?

Infective endocarditis Signup and view all the answers

What is a significant complication of the condition described?

Congestive heart failure Signup and view all the answers

Which factor is suggested as an intrinsic defect in the pathogenesis of the condition?

Extracellular matrix remodeling Signup and view all the answers

Which type of bacteria is primarily responsible for infective endocarditis?

Extracellular bacteria Signup and view all the answers

What histological change is associated with the condition outlined?

Thinning of the fibrosa layer Signup and view all the answers

What is the primary characteristic of stenosis in valvular heart disease?

Failure of a valve to open completely Signup and view all the answers

What is a common feature associated with mitral valve prolapse?

Floppy or ballooning of mitral leaflets Signup and view all the answers

Which of the following risk factors is associated with calcific aortic stenosis?

Presence of a bicuspid aortic valve Signup and view all the answers

Which outcome resembles the effects of severe calcific aortic stenosis?

Concentric left ventricular hypertrophy Signup and view all the answers

What is a primary cause of regurgitation in valvular heart disease?

Intrinsic disease of the valve cusps Signup and view all the answers

Which statement is true regarding the manifestation of calcific aortic stenosis in anatomically normal valves?

Manifestation begins in the 70s and 80s. Signup and view all the answers

Which of the following features is typically observed in both stenosis and insufficiency of heart valves?

Presence of murmurs Signup and view all the answers

What is the significance of age-related wear and tear in relation to calcific aortic stenosis?

It is a common factor in older adults. Signup and view all the answers

What is a potential underlying cause of mitral valve prolapse as indicated in the content?

Intrinsic defect of connective tissue Signup and view all the answers

What histological change is noted in the mitral valve associated with the discussed condition?

Thinning of the fibrosa layer Signup and view all the answers

Which of the following is a common clinical finding during auscultation for mitral valve prolapse?

Midsystolic click Signup and view all the answers

In which condition can infective endocarditis result, affecting heart valves and endocardium?

Microbial infection Signup and view all the answers

What characterizes the vegetations formed in infective endocarditis?

Bulky and friable Signup and view all the answers

Which group of bacteria is considered a common cause of infective endocarditis?

Extracellular bacteria Signup and view all the answers

What is the clinical symptom that often accompanies mitral valve prolapse?

Palpitations Signup and view all the answers

Which statement describes the morphology of the mitral leaflets in mitral valve prolapse?

They are enlarged and rubbery Signup and view all the answers

What primarily causes stenosis in valvular heart diseases?

Primary cuspal abnormality Signup and view all the answers

In which condition does backflow of blood occur due to valve failure?

Insufficiency (Regurgitation) Signup and view all the answers

What is a common feature of mitral valve prolapse?

Leaflets balloon back into the left atrium Signup and view all the answers

What defines the morphology of calcific aortic stenosis?

Heaped-up calcified masses on the outflow side Signup and view all the answers

At what age do patients with anatomically normal valves typically begin to show symptoms of severe calcific stenosis?

70-80 years Signup and view all the answers

What condition arises from the age-related degeneration and arteriosclerosis of heart valves?

Calcific aortic stenosis Signup and view all the answers

Which factor contributes to the complication of chronic heart failure in severe calcific aortic stenosis?

Lowered cardiac output due to stenosis Signup and view all the answers

What is a characteristic consequence of left ventricular outflow obstruction caused by severe calcific aortic stenosis?

Concentric left ventricular hypertrophy Signup and view all the answers

What is the primary consequence of chronic increase in preload?

Cardiac muscle dilatation Signup and view all the answers

Which of the following conditions is associated with high afterload?

Hypertension Signup and view all the answers

In the context of the Fick principle, what does 'Q' represent?

The substance added by the organ Signup and view all the answers

What does an increase in stroke volume indicate in relation to cardiac performance?

Increased preload Signup and view all the answers

Which of the following methods is used for direct measurement of cardiac output?

Electromagnetic flow-meter devices Signup and view all the answers

How does the Fick principle relate to the function of the lungs?

It assesses oxygen consumption by the lungs Signup and view all the answers

What is the formula used to calculate cardiac output in the Hamilton dye dilution method?

COP = (Q x 60) / (C x t) Signup and view all the answers

In relation to venous return, what is a key factor influencing its efficiency?

Pressure gradient Signup and view all the answers

Which factor most directly influences the end diastolic volume (EDV)?

Venous return Signup and view all the answers

What is the primary consequence of decreased contractility on stroke volume?

Decreased stroke volume Signup and view all the answers

Which variable is used to calculate the ejection fraction (EF)?

Stroke volume and end diastolic volume Signup and view all the answers

In what way does physical training specifically affect stroke volume?

It raises stroke volume Signup and view all the answers

What does a high preload indicate regarding the volume of blood in the heart?

Increased blood volume returning to the heart Signup and view all the answers

What effect do thyroid hormones have on stroke volume?

Increase stroke volume Signup and view all the answers

Which statement accurately describes the relationship between preload and stroke volume?

Increased preload increases stroke volume Signup and view all the answers

What physiological change occurs when preload remains elevated for an extended period?

Potential heart muscle fatigue Signup and view all the answers

Which neural factor increases stroke volume?

Sympathetic activity Signup and view all the answers

What primarily defines the preload in the context of cardiac function?

Blood volume before contraction Signup and view all the answers

What is the primary factor that influences stroke volume during physical activity?

Venous return to the heart Signup and view all the answers

Which component of the cardiac output calculation can be directly altered by changes in venous return?

Stroke volume Signup and view all the answers

What does a significant decrease in ejection fraction typically indicate regarding heart function?

Diminished cardiac output and potential heart failure Signup and view all the answers

What role does preload play in the regulation of stroke volume?

It increases stroke volume by enhancing ventricular filling Signup and view all the answers

Which factor would most likely lead to increased afterload on the heart?

Increased peripheral resistance Signup and view all the answers

Which condition is associated with decreased preload affecting stroke volume?

Dehydration Signup and view all the answers

How does an increase in heart rate potentially affect stroke volume?

It decreases stroke volume due to reduced filling time Signup and view all the answers

What is the relationship between stroke volume and cardiac output?

Cardiac output equals stroke volume multiplied by heart rate Signup and view all the answers

What is cardiac output (COP) defined as?

The volume of blood ejected by each ventricle per minute Signup and view all the answers

Which factor influences heart rate (HR) by decreasing its value?

Parasympathetic nervous system activity Signup and view all the answers

What is the primary formula to calculate cardiac output?

COP = Heart Rate x Stroke Volume Signup and view all the answers

How does physical activity typically affect stroke volume?

Generally increases it in healthy individuals Signup and view all the answers

What is considered a normal resting heart rate for adults?

60-100 beats per minute Signup and view all the answers

Which of the following factors has a positive chronotropic effect on heart rate?

Catecholamines Signup and view all the answers

What is the relationship between heart rate and stroke volume when heart rate is very high?

Stroke volume may decrease Signup and view all the answers

Which hormones are known to increase heart rate significantly?

Thyroid hormones and catecholamines Signup and view all the answers

What does an increase in afterload primarily indicate?

Increased force needed for the heart to eject blood Signup and view all the answers

Which method is classified as an indirect method for measuring cardiac output?

Thermodilution method Signup and view all the answers

What is the correct formula according to the Fick principle for calculating blood flow?

Blood flow = Q / [A] - [V] Signup and view all the answers

Which condition is influenced by high afterload?

Hypertension Signup and view all the answers

In the Hamilton dye dilution method, what does 'C' represent?

Concentration of the dye in the arterial blood sample Signup and view all the answers

What effect does chronic increase in preload have on cardiac function?

Dilatation of cardiac muscle leading to weakness Signup and view all the answers

According to the Fick principle, what substance is consumed by the lungs to determine blood flow?

Oxygen Signup and view all the answers

What is the primary significance of venous return in cardiac physiology?

It aids in maintaining stroke volume Signup and view all the answers

What primarily determines the end diastolic volume (EDV)?

Venous return Signup and view all the answers

Which factor has no direct effect on stroke volume?

Parasympathetic activity Signup and view all the answers

How is ejection fraction (EF) calculated?

Stroke volume / End diastolic volume x 100% Signup and view all the answers

What physiological principle relates stroke volume to the initial length of muscle fibers?

Frank-Starling Law Signup and view all the answers

Which effect do catecholamines have on stroke volume?

They increase stroke volume. Signup and view all the answers

Which condition causes stroke volume to increase during exercise?

Increased venous return Signup and view all the answers

What describes the effect of fever on stroke volume?

Increases stroke volume Signup and view all the answers

What is the consequence of prolonged high preload on the heart?

Hypertrophy of heart muscles Signup and view all the answers

What effect does the sympathetic nervous system have on stroke volume?

Increases stroke volume Signup and view all the answers

What factor is indicative of myocardial contractility?

Ejection fraction Signup and view all the answers

Study Notes

Valvular Heart Disease (VHD)

VHD can result in stenosis or insufficiency (regurgitation) or both.
Stenosis: Failure of a valve to open completely, impeding forward blood flow. Commonly caused by calcification or scarring of the valve cusps.
Insufficiency (Regurgitation): Failure of a valve to close completely, allowing reversed blood flow (backflow). This is caused by intrinsic valve cusp disease or disruption of supporting structures.
Valve abnormalities can be congenital or acquired (e.g., bicuspid aortic valve).
Valve abnormalities lead to abnormal blood flow, causing murmurs.

Pathophysiological Mechanisms of Heart Disease

Pump Failure: Systolic or diastolic dysfunction; results in decreased cardiac output.
Flow Obstruction: Lesions prevent valve opening (e.g., calcific aortic stenosis) or increase ventricular chamber pressure.
Regurgitant Flow: Results in volume overload in affected chambers due to valve lesions.
Shunted Flow: Results in pressure and volume overload.
Conduction Disorders: Arrhythmias lead to decreased contraction frequency and reduced effective cardiac output.
Major Vessel or Heart Rupture: May lead to hypotension, shock, and potential death.

Heart Valve Anatomy and Histology

Heart valves include aortic, mitral, pulmonary and tricuspid valves.
Chordae tendineae that consist of collagen and are covered by endothelium.
Valves have distinct layers.

Etiology of Acquired Heart Valve Disease

Mitral Valve Disease: Mitral stenosis (post-inflammatory scarring, rheumatic heart disease), mitral regurgitation (abnormalities of leaflets and commissures, post-inflammatory scarring, infective endocarditis, mitral valve prolapse, “fen-phen”-induced valvular fibrosis, rupture of papillary muscle), and more are possible causes
Aortic Valve Disease: Aortic stenosis (post-inflammatory scarring, rheumatic heart disease, senile calcific aortic stenosis, calcification of congenitally deformed valve), and aortic regurgitation (intrinsic valvular disease, post-inflammatory scarring, infective endocarditis, aortic disease, degenerative aortic dilation, syphilitic aortitis, ankylosing spondylitis, rheumatoid arthritis, Marfan syndrome).

Calcific Aortic Stenosis

A degenerative valve disease.
Most common cause of aortic stenosis.
Age-related wear and tear.
Age-related arteriosclerosis.
Risk factors: Male, high LDL, hypertension, and smoking.
Morphology: Heaped-up calcified masses on the outflow side of the cusps, cuspal calcification and fibrosis.

Clinical Features of Calcific Aortic Stenosis

Anatomically normal valves → manifestation in 70s and 80s.
In bicuspid valves → early onset (40-50 years).
Severe calcific aortic stenosis → left ventricular outflow obstruction, left ventricular pressure increase, leading to concentric left ventricular hypertrophy.

Consequences of Calcific Aortic Stenosis

Hypertrophy of Myocardium
Poor Brain Perfusion
Ischemic Angina
Syncope
Systolic Dysfunction
Diastolic Dysfunction
Chronic Heart Failure (CHF)
Cardiac Decompensation

Mitral Valve Prolapse (Myxomatous Mitral Valve)

One or both mitral leaflets are floppy and balloon back into the left atrium during systole.
Women are affected more than men.
Can be primary (idiopathic) or secondary.
Morphology: Characterized by ballooning or prolapse of mitral leaflets, and enlarged, redundant, rubbery leaflets. Tendinous cords become elongated, thinned, and occasionally ruptured.

Histological appearance of Mitral Valve Prolapse

Thinning of the fibrosa layer of the valve.
Extension of the middle spongiosa layer with increased deposition of myxomatous (mucoid) material.

Pathogenesis of Mitral Valve Prolapse

Largely unknown.
Underlying intrinsic defect of connective tissue synthesis or remodeling.
Common features of Marfan syndrome.

Clinical Features of Mitral Valve Prolapse

Majority asymptomatic.
Symptoms: Palpitations, dyspnea, or atypical chest pain.
Auscultation: Midsystolic click with or without an associated regurgitant murmur.

Complications of Mitral Valve Prolapse

Embolism Risk.
Sudden Cardiac Death (SCD) Risk
Infective Endocarditis Risk, Mitral Regurgitation, Congestive Heart Failure (CHF).

Infective Endocarditis (IE)

Characterized by microbial infection of heart valves or mural endocardium.
Often with destruction of the underlying cardiac tissues.
Resulting in bulky, friable vegetations composed of necrotic debris, thrombus and organisms.
Majorly caused by extracellular bacteria.

Classification of Infective Endocarditis

Acute Endocarditis: High virulence organisms (e.g., Staphylococcus aureus), destructive lesions, substantial morbidity and mortality
Subacute Endocarditis: Low virulence organisms (e.g., Streptococcus viridans), insidious onset, protracted course with recovery with antibiotics.

Pathogenesis of Infective Endocarditis

Causative microorganisms (Streptococcus viridans, Staphylococcus aureus, HACEK group, Gram-negative bacilli, fungi, culture-negative (10%).
Valvular conditions (RHD, mitral valve prolapse, bicuspid aortic valve, calcific valvular stenosis, prosthetic heart valves).

Host Risk Factors for Infective Endocarditis

Alcohol or IV drug abuse
Diabetes Mellitus
Therapeutic immunosuppression
Neutropenia
Immunodeficiency
Malignancy
Predisposing condition: Seeding of blood with microbes, dental or surgical procedure bacteremia, injection of contaminated material.

Morphology of Vegetations in Infective Endocarditis

Friable, bulky, and destructive vegetations on heart valves.
Made up of fibrin, inflammatory cells, and microorganisms.
May involve single or multiple valves.
Commonly found on aortic & mitral valves (commonest).

Complications of Infective Endocarditis

Erosion into underlying myocardium with abscess formation.
Acute IE of congenitally bicuspid aortic valve.
Staph. Aureus.
Ring abscess
Systemic emboli, Septic infarcts, mycotic aneurysms.
presence of virulent organisms
Subacute IE vegetations have granulation tissue at bases - fibrosis, calcification, chronic inflammatory infiltrate.

Clinical features in IE

acute IE = rapid onset with fever, chills and weakness
subacute IE = gradual onset with fatigue, weight loss, flu-like symptoms and splenomegaly
vegetation patterns in different diseases: Rheumatic heart disease (RHD) , Infective endocarditis (IE), Nonbacterial thrombotic endocarditis (NBTE). Libman-Sacks endocarditis (LSE)

Petechiae (small red or purple spots)
Janeway lesions (painless erythematous lesions, found on palms and soles)
Nail bed hemorrhages (splinter hemorrhages)
Retinal hemorrhages (Roth spots)
Osler nodes (painful fingertip nodules)

Diagnosis of Infective Endocarditis

Positive blood cultures.
Echocardiographic findings.

Complications of Infective Endocarditis

Glomerulonephritis, hematuria, albuminuria, renal failure
Systemic embolization
Septicemia
Arrhythmias

Non-Infected Vegetations (Nonbacterial Thrombotic Endocarditis (NBTE) )

Characterized by deposition of small sterile thrombi (vegetation) on the leaflets of cardiac valves.
Sterile valvular lesions usually on previously normal valves.
Morphology: Sterile, non-destructive, small vegetations, may be single or multiple, bland thrombus without inflammation or valve damage

Morphology of Non-infected Vegetations(NBTE)

Sterile, non-destructive small vegetations.
May be single or multiple.
Bland thrombus without inflammation or valve damage

Pathogenesis of Non-Infected Vegetations (NBTE)

Symptoms due to embolization to the heart, brain, or other organs.
Potential nidus of bacterial colonization and IE development.

Libman-Sacks Endocarditis (LSE)

Sterile vegetations.
Immune complex deposition.
Inflammation + fibrinoid necrosis of valve.
Characteristics: Sterile vegetations, immune-mediated inflammation and fibrinoid necrosis.
Vegetations locations: valve surface, chordae, atrial and ventricular endocardium.

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Description

This quiz covers key concepts related to Valvular Heart Disease (VHD), including its types, mechanisms, and pathophysiological implications. Understand the differences between stenosis and insufficiency, as well as their causes and effects on blood flow. Test your knowledge on congenital and acquired valve abnormalities and their impact on heart function.