Ch. 18 - Valvular Disorders and Cardiomyopathy

Pathophysiology Exam 2

What is the primary function of the heart valves?

To ensure one-way blood flow through the heart and prevent backflow

How many heat valves are there?

Four

What are the four heart valves?

Tricuspid, pulmonary, mitral (bicuspid), and aortic

Which valve separates the right atrium from the right ventricle?

The tricuspid valve

Which valve separates the left atrium from the left ventricle?

The mitral (bicuspid) valve

Which valve is located between the right ventricle and pulmonary artery?

The pulmonary valve

Which valve is located between the left ventricle and the aorta?

The aortic valve

What happens when a heart valve becomes stenotic?

The valve becomes narrowed, reducing forward blood flow

What happens when a heart valve becomes insufficient (regurgitant)?

The valve does not close properly, allowing blood to flow backward

What is valvular stenosis?

Narrowing of heart valve that obstruct blood flow

What is valvular insufficiency (regurgitation)?

Failure of a valve to close completely, allowing blood to leak backward

Which valve disorder is specifically listed in your study guide?

Mitral valve stenosis

What is mitral valve stenosis?

Narrowing of the mitral valve that restricts blood flow from the left atrium to the left ventricle

What is the most common cause of mitral valve stenosis worldwide?

Rheumatic fever

What happens to the left atrium in mitral stenosis?

Pressure increases, causing left atrial enlargement

Why does mitral stenosis increase pressure in the lungs?

Blood backs up from the left atrium into the pulmonary veins

What are the common symptoms of mitral stenosis?

Dyspnea, fatigue, exercise intolerance, orthopnea, and paroxysmal nocturnal dyspnea

Why does dyspnea occur in mitral stenosis?

Pulmonary congestion develops as blood backs up into the lungs

Why is fatigue common in mitral stenosis?

Less blood reaches the left ventricle, reducing cardiac output

What abnormal heart rhythm commonly develops in mitral stenosis?

Atrial fibrillation

Why does atrial fibrillation commonly occur in mitral stenosis?

Enlargement of the left atrium disrupts normal electrical conduction

What serious complication can result from atrial fibrillation in mitral stenosis?

A stroke due to thrombus formation

What murmur is commonly heard with mitral stenosis

A diastolic murmur

What diagnostic test best confirms mitral stenosis?

Echocardiogram

How is mild mitral stenosis treated?

Medications to manage symptoms and prevent complications

What medications may be used for mitral stenosis?

Diuretics, beta blockers or calcium channel blockers (for rate control if indicated), and anticoagulants if atrial fibrillation is present

When is surgery considered for mitral stenosis?

When symptoms become severe or the valve is critically narrowed

What procedure can be performed to widen a narrowed mitral valve without replacing it in selected patients?

Balloon valvotomy (balloon valvuloplasty)

What is the long-term effect of untreated severe mitral stenosis?

Progressive pulmonary hypertension and heart failure

What is pulmonary hypertension?

Abnormally high blood pressure in the pulmonary arteries, making it harder for the right ventricle to pump blood through the lungs

What is mitral valve insufficiency (mitral regurgitation)?

A disorder in which the mitral valve does not close completely, allowing blood to flow backward from the left ventricle into the left atrium during systole

What is another name for mitral valve insufficiency?

Mitral regurgitation

During which phase of the cardiac cycle does mitral valve regurgitation occur?

Systole (ventricular contraction)

What causes blood to flow backward in mitral regurgitation?

The mitral valve fails to close completely during ventricular contraction

What are common causes of mitral regurgitation?

Mitral valve prolapse, rheumatic heart disease, infective endocarditis, myocardial infarction, papillary muscle dysfunction, and degenerative valve disease

How does a myocardial infarction cause mitral regurgitation?

Damage to the papillary muscles or chordae tendineae prevents the mitral valve from from closing properly

What happens to the left atrium during mitral regurgitation?

It enlarges because it receives blood from both the pulmonary veins and the leaking mitral valve

What happens to the left ventricle in chronic mitral regurgitation?

It enlarges due to chronic volume overload

Why does mitral regurgitation decrease cardiac output?

Some of the blood is pumped backward into the left atrium instead of forward into the aorta

What are the common signs and symptoms of mitral regurgitation?

Fatigue, dyspnea, palpitations, exercise intolerance, and pulmonary congestion

Why does pulmonary congestion occur in mitral regurgitation?

Blood backs up into the pulmonary veins, increasing pressure in the lungsW

hat heart sound is commonly heart in mitral regurgitation?

A systolic murmur

Which diagnostic test best evaluates mitral regurgitation?

Echocardiogram

How is mild mitral regurgitation treated?

Medications to reduce symptoms and regular monitoring

When is surgery recommended for mitral regurgitation?

When symptoms are severe or left ventricular function begins to decline

What surgical treatments are available for severe mitral regurgitation?

Mitral valve repair or mitral valve replacement

What is the difference between mitral stenosis and mitral regurgitation?

Mitral stenosis is narrowing of the valve that obstructs forward blood flow, while mitral regurgitation is incomplete valve closure that allows backward blood flow

Which condition causes pressure overload of the left atrium?

Mitral stenosis

Which condition causes volume overload of the left atrium?

Mitral regurgitation

Which valve disorder is most likely to produce a diastolic murmur?

Mitral stenosis

Which calve disorder is more likely to produce a systolic murmur?

Mitral regurgitation

What is hypertrophic cardiomyopathy (HCM)?

A disease in which the heart muscle becomes abnormally thick, making ir harder for the heart to pump blood

Which part of the heart is most commonly affected in hypertrophic cardiomyopathy?

The interventricular septum

What is the most common cause of hypertrophic cardiomyopathy?

An inherited genetic mutation affecting cardiac muscle proteins

How does hypertrophic cardiomyopathy affect cardiac output?

Thickened heart muscle reduces ventricular filling and may obstruct blood leaving the left ventricle, decreasing cardiac output

Why does hypertrophic cardiomyopathy inpair ventricular filling?

The thickened ventricular wall becomes stiff and less able to relax during diastole

What are common symptoms of hypertrophic cardiomyopathy?

Chest pain, shortness of breath, dizziness, syncope, palpitations, and exercise intolerance

Why can syncope occur in hypertrophic cardiomyopathy?

Obstruction of blood flow or abnormal heart rhythms can temporarily reduce blood flow to the brain

Why are patients with hypertrophic cardiomyopathy at increased risk for sudden cardiac death?

They are at increased risk for life-threatening ventricular arrhythmias

Which population is classically associated with sudden cardiac death from hypertrophic cardiomyopathy?

Young athletes during to immediately after strenuous exercise

How is hypertrophic cardiomyopathy (HCM) diagnosed?

Echocardiogram is the primary diagnostic test; ECG and cardiac MRI may also be used

What does an echocardiogram show in hypertrophic cardiomyopathy?

Thickened ventricular walls (often the interventricular septum), impaired ventricular filling, and sometimes left ventricular outflow tract obstruction

Why is an ECG often abnormal in hypertrophic cardiomyopathy?

The thickened heart muscle alters normal electrical conduction and can lead to arrhythmias

What is left ventricular outflow tract (LVOT) obstruction?

A blockage of blood leaving the left ventricle caused by the thickened septum narrowing the outflow tract

Why does LVOT obstruction worsen symptoms in HCM?

It reduces the amount of blood ejected into the aorta decreasing cardiac output

What medications are commonly used to treat hypertrophic cardiomyopathy?

Beta blockers and calcium channel blockers

Why are beta blockers used in HCM?

They slow the heart rate, allowing more time for ventricular filling and reducing myocardial oxygen demand

Why are calcium channel blockers used in HCM?

They improve ventricular relaxation and reduce symptoms

When may surgery be considered for hypertrophic cardiomyopathy?

When severe symptoms persist despite medication or significant LVOT obstruction is present

What is a septal myectomy?

A surgical procedure that removes part of the thickened interventricular septum to improve blood flow

What is an implantable cardioverter-defibrillator (ICD)?

A device that detects and treats life-threatening ventricular arrhythmias by delivering an electrical shock when needed

Which patients with HCM may benefit from an ICD?

Patients at high risk for sudden cardiac death, such as those with prior cardiac arrest, sustained ventricular arrhythmias, or other high risk features

Why are strenuous sports often discouraged in some patients with HCM?

Intense exercise may increase the risk of dangerous arrhythmias and sudden cardiac death

What is the overall goal of treating hypertrophic cardiomyopathy?

Relieve symptoms, improve cardiac output, prevent arrhythmias, and reduce the risk of sudden cardiac death

What is the difference between valvular heart disease and cardiomyopathy?

Valvular heart disease affects the heart valves, while cardiomyopathy primarily affects the heart musce

What is the difference between stenosis and insufficiency (regurgitation)?

Stenosis is narrowing of a valve that restricts forward blood flow; insufficiency is incomplete valve closure that allows backward flow

Which condition primarily causes an obstruction to forward blood flow?

Stenosis

Which condition primarily causes backward flow?

Regurgitation

Which valve disorder listed in your study guide is most commonly associated with atrial fibrillation?

Mitral valve stenosis

Why does mitral valve stenosis increase the risk of atrial fibrillation?

Increased pressure enlarges the left atrium, disrupting normal electrical conduction

Which valve strider causes blood to flow backward into the left atrium during systole?

Mitral regurgitation

Which valve disorder makes it difficult for blood to move from the left atrium to the left ventricle?

Mitral stenosis

Which disorder causes pressure overload of the left atrium?

Mitral stenosis

Which disorder causes volume overload of the left atrium?

Mitral regurgitation

Which chamber is most affected in mitral valve disease?

The left atrium

Which chamber becomes abnormally thick in hypertrophic cardiomyopathy?

The left ventricle, especially the interventricular septum

Which condition is most associated with sudden cardiac death in young athletes?

Hypertrophic cardiomyopathy

What is the most important diagnostic test for both mitral valve disorders and hypertrophic cardiomyopathy?

Echocardiogram

What are the three major disorders covered in this chapter (ch. 18)?

Mitral valve stenosis, mitral valve regurgitation (insufficiency), hypertrophic cardiomyopathy

What is the most important thing to remember?

Valve disease either blocked forward blood flow (stenosis) or allows backward blood flow (regurgitation), while hypertrophic cardiomyopathy is a disease of the heart muscle that impairs ventricular filling and can obstruct blood flow