Ch. 17 - Cardiac Function and Heart Failure

Pathophysiology Exam 2

What is cardiac contractility?

The ability of the heart muscle to contract and generate force to pump blood

Why is cardiac contractility important?

It determines how effectively the heart can eject blood to the body

What happens when cardiac contractility decreases?

Cardiac output decreased, causing poor tissue perfusion

What conditions can decrease cardiac contractility?

Myocardial infarction, heart failure, cardiomyopathy, and damage to heart muscle

What is cardiac output?

The amount of blood the heart pumps each minute

What is the formula for cardiac output?

Cardiac output = heart rate X stroke volume

What is stroke volume?

The amount of blood pumped from a ventricle with each heartbeat

What are the three factors that affect stroke volume?

Preload, after load, and contractility

What is preload?

The amount of ventricular filling and stretch before contraction

What is after load?

The resistance the ventricle must overcome to eject blood

How does increased after load affect the heart?

It makes the heart work harder and can eventually lead to heart failure

What is heart failure?

A condition where the heart cannot pump enough blood to meet the body’s needs

Is heart failure the same as the heart stopping?

No, heart failure means the heart’s pumping ability is impairedW

What are the two main types of heart failure?

Left-sided heart failure and right-sided heart failure

What causes left-sided heart failure?

Hypertension, coronary artery disease, myocardial infarction, and valve disorders

What happens in left-sided heart failure?

Blood backs up into the lungs because the left ventricle cannot pump effectively

What are symptoms of left-sided heart failure?

Dyspnea, orthopnea, pulmonary edema, crackles, fatigue, and cough

What is orthopnea?

Shortness of breath that occurs when lying flat and improves when sitting up

Why does left-sided heart failure cause pulmonary edema?

Blood backs up into pulmonary vessels, increasing pressure and pushing into lung tissue

What lung sounds may be heard with left-sided heart failure?

Crackles (rales)

What is paroxysmal nocturnal dyspnea (PND)?

Sudden nighttime shortness of breath that wakes a person from sleep

What is right-sided heart failure?

Failure of the right ventricle to pump blood effectively into pulmonary circulation

What is the most common cause of right-sided heart failure?

Left-sided heart failure

What happens in right-sided heart failure?

Blood backs up into systemic veins and body tissues

What are symptoms of right-sided heart failure?

Peripheral edema, jugular vein distension (JVD), ascites, weight gain, and hepatomegaly

What is jugular venous distention (JVD)?

Visible neck vein swelling caused by increased venous pressure

Why does right-sided heart failure cause peripheral edema?

Increased venous pressure pushes fluid into tissuesW

What Is ascites?

Accumulation of fluid in the abdominal cavity

What is hepatomegaly?

Enlargement of the liver due to blood congestionW

What is the major difference between left and right heart failure?

Left-sided failure affects the lungs; right sided failure affects systemic circulation

What is mitral regurgitation (mitral insufficiency)?

A condition where the mitral valve does not close properly, allowing blood to flow backward from the left ventricle into the left atrium during systole

What is the normal function of the mitral valve?

It allows blood to flow from the left atrium to the left ventricle and prevents backwards flow

What causes blood to leak backward in mitral regurgitation?

Incomplete closure of the mitral valve

What happens to the left atrium in mitral regurgitation?

It becomes enlarged due to increased blood volume from regurgitation

What happens to the left ventricle in chronic mitral regurgitation?

It enlarges an may eventually weaken from increased workloadW

What are common causes of mitral regurgitation?

Mitral valve damage, rheumatic heart disease, infection (endocarditis), ischemic heart disease, and valve degeneration

What type of murmur is heard with mitral regurgitation?

A systolic murmur

What are symptoms of mitral regurgitation?

Fatigue, shortness of breath f breath, palpitations, reduced exercise tolerance, and signs of heart failure

Why can mitral regurgitation cause pulmonary congestion?

Blood backs up into the left atrium and pulmonary circulation, increasing pressure in the lungs

How is mitral regurgitation diagnosed?

Echocardiogram, physical exam, and imaging studies

What is the treatment goal for mitral regurgitation?

Reduce symptoms, decrease workload on heart, and repair or replace the valve if severeWh

What medications may be used for mitral regurgitation symptoms?

Diuretics, vasodilators, and medications that reduce cardiac workload

When may surgery be needed for mitral regurgitation?

When symptoms are severe or the valve dysfunction significantly affects the heart function

What is compensated heart failure?

A stage where the body uses mechanisms to maintain cardiac output despite impaired heart function

What systems compensate when cardiac output decreases?

The sympathetic nervous system and the RAAS system

What does the sympathetic nervous system do during heart failure?

increases heart rate and contractility to maintain blood pressure

What hormone is released when the sympathetic nervous system is activated?

Epinephrine and norepinephrineWh

What does RAAS activation cause during heart failure?

Vasoconstriction and sodium/water retention

Why does the body retain fluid during heart failure?

To increase blood volume and maintain blood pressure, but it eventually worsens congestion

What is the problem with long-term activation of compensatory mechanisms?

They increase the workload on the heart and worsen heart failure progression

What is decompensated heart failure?

A worsening state where compensation fails and symptoms become severe

What are signs of worsening heart failure?

Increasing shortness of breath, edema, weight gain, fatigue, and decreased activity tolerance

Why does weight increase in fluid overload heart failure?

Fluid retention causes increased body weight

What is a common daily weight monitoring recommendation for heart failure patients?

Monitor weight daily to detect fluid retention early

What weight change may indicate worsening fluid retention?

A rapid gain of about 2-3 pounds in a day or 5 pounds in a week (commonly used clinical guideline)

What is the purpose of diuretics in heart failure?

Remove excess fluid and reduce edema and pulmonary congestion

What is the purpose of ACE inhibitors in heart failure?

Reduced after load, decrease blood pressure, and reduce harmful cardiac remodeling

What is the purpose of beta blockers in chronic heart failure?

Reduce sympathetic stimulation and improve heart function over time

What lifestyle changes help manage heart failure?

Low-sodium diet, fluid management when prescribed, exercise as tolerated, weight monitoring, and medication adherance

What is the overall goal of heart failure treatment?

Improve quality of life, reduce symptoms, prevent progression, and decrease hospitalization

What laboratory test is commonly elevated in heart failure?

B natriuretic peptide (BNP) or N-terminal pro-BNP (NT-proBNP)

Why are BNP levels elevated in heart failure?

The ventricles release BNP in response to increased stretching from excess blood volume and pressure

What does an elevated BNP level suggest?

Heart failure or increased ventricular stress

What is the best imaging test for evaluating heart failure?

Echocardiography (echocardiogram)

What information does an echocardiogram provide in heart failure?

Ejection fraction, chamber size, valve function, wall motion, and overall cardiac function

What is reduced ejection fraction (HFrEF)?

Heart failure with reduced ejection fraction, where the heart has weakened pumping ability

What is preserved ejection fraction (HFpEF)?

Heart failure in which the heart contracts normally but does not relax and fill properly

Which type of heart failure is considered systolic dysfunction?

Heart failure with reduced ejection fraction (HFrEF)

Which type of heart failure is considered diastolic dysfunction?

Heart failure with preserved ejection fraction (HFpEF)

What is the difference between systolic and diastolic heart failure?

Systolic heart failure involves impaired contraction; diastolic heart failure involves impaired relaxation and filling

Why do patients with heart failure become fatigued?

Decreased cardiac output reduces oxygen delivery to tissues

Why is exercise intolerance common in heart failure?

The heart cannot increase cardiac output enough to meet the body’s demands during activity

Why does heart failure cause decreased urine output during the day?

Reduced cardiac output decreases kidney perfusion, reducing urine production

Why do some heart failure patients urinate more at night?

Lying down improves kidney blood flow, increasing uring production

What is nocturia?

Frequent urination during the night

Why are heart failure patients advised to limit sodium intake?

Excess sodium causes water retention, worsening edema and increasing cardiac workload

Why may some heart failure patients have a fluid restriction?

To help prevent fluid overload and worsening congestion

Why should patients with heart failure weigh themselves every morning?

Rapid weight gain is often the earliest sign of fluid retention

What symptoms should a heart failure patient report immediately?

Rapid weight gain, worsening shortness of breath, increased swelling, chest pain, dizziness, or fainting

What position often helps relieve shortness of breath in heart failure?

Sitting upright or in High Fowler’s position

Why does sitting upright improve breathing in heart failure?

It reduces venous return to the heart and decreases pulmonary congestion

What is pulmonary edema?

Fluid accumulation in the alveoli and lung tissue caused by increased pressure in the pulmonary circulation

What are signs and symptoms of pulmonary edema?

Severe shortness of breath, crackles, pink frothy sputum, tachypnea, anxiety, and hypoxemia

Why is pulmonary edema considered a medical emergency?

It severely impairs oxygen exchange and can rapidly lead to respiratory failure

What is the primary goal when treating acute pulmonary edema?

Improve oxygenation and reduce fluid overload

What medications are commonly used to treat acute pulmonary edema?

Diuretics, oxygen, vasodilators (when appropriate), and other therapies based on the patient’s condition

What is the prognosis of untreated heart failure?

It progressively worsens and can eventually lead to severe disability or death

Can heart failure be cured?

Most cases cannot be cured, but they can often be effectively managed with medications, lifestyle changes, and treatment of the underlying cause

What are the primary goals of heart failure management?

Relieve symptoms, improve cardiac function, slow disease progression, prevent complications, and improve quality of life

What are the hallmark differences between left-sided and right-sided heart failure?

Left-sided heart failure causes pulmonary congestion (lungs), while right-sided heart failure causes systemic venous congestion (peripheral edema, JVD, ascites)