Introduction

According to the American Heart Association, there are approximately 5 million people in the United States living with congestive heart failure (CHF), or heart failure, and approximately 550,000 new CHF cases each year. The body depends on the ability of the heart to pump oxygenated and nutrient-rich blood through blood vessels to the rest of the body adequately. When the cells have enough oxygen and nutrients from blood, the body can function normally. CHF results from an underlying cardiac condition that impairs the ability of heart pump a sufficient amount of blood throughout the body to satisfy the needs of the cells of the body. The blood returning to the heart through the veins backs up, causing congestion in the tissues. With CHF, the heart cannot supply the cells with enough blood and thus, oxygen and nutrients.

Classifications:

There are many different classifications of CHF.

1. Left-sided vs. Right-sided
2. Forward vs. Backward
3. Acute vs. Chronic
4. Systolic vs. Diastolic
5. High output vs. low output

Left-sided vs. Right-Sided CHF

CHF can occur in different locations in the heart. The heart is divided into left and right sides. Both halves have two chambers, the atrium and the ventricle. The atrium is located above the ventricle. In the blood flow through the heart, deoxygenated blood from the veins enters the right atrium and the right ventricle pumps the blood to the lungs to collect oxygen. Blood returns from the lungs to the left atrium and the left ventricle pumps the blood through the arteries to the body. CHF occurs when any of these four chambers weakens and does not pump adequately.

Left-sided heart failure or left ventricular ( LV ) heart failure: When the left ventricle does not pump enough blood, the blood backs up into the lungs, causing pulmonary edema (build-up of fluid in lungs). LV heart failure tends to cause right-sided heart failure.

Right-sided heart failure or right ventricular (RV) heart failure: When the right ventricle does not pump enough blood, the blood backs up into body's veins, causing systemic edema (build-up of fluid in tissues, usually the lower extremities).

Backward vs. Forward CHF

Backward Heart Failure: One of the ventricles fails to pump out all of its blood that comes into it. Thus, the ventricular filling pressure and systemic or pulmonary edema increase.

Forward Heart Failure: The heart is not pumping out enough blood to satisfy the needs of the cells of the body. Thus, excess fluid retention and edema increase.

Acute vs. Chronic CHF

Acute heart failure: When an individual develops CHF suddenly, such as during a myocardial infarction when a large part of cardiac muscle dies or during a rupture of a cardiac valve, the heart cannot pump out enough blood.

Chronic heart failure: An individual who develops CHF gradually.

Systolic vs. Diastolic Failure

The heart can be in either of the two phases of the cardiac cycle: contraction (systole) and rest (diastole).

Systolic heart failure: The left ventricle does not contract normally and does not pumping out enough blood. This type of heart failure causes weakness, fatigue and decreased exercise ability.

Diastolic heart failure: The left ventricle is unable to relax normally and cannot fill properly during diastole. This type of heart failure causes systemic or pulmonary edema.

High Output vs. Low Output Heart Failure

High-output heart failure : This type of heart failure occurs when the cardiac output is normal or high, but demand for blood flow is abnormally high and the heart is unable to satisfy the demand.

Low-output failure : This type of heart failure occurs when the c ardiac output is low, but demand for blood flow is normal and the heart is unable to satisfy this demand.

How the Body Compensates for a Failing Heart

CHF usually develops slowly. As the heart fails, the body tries to compensate for the changes to maintain the cardiac output and blood flow to the organs by:

• Enlarging in size. The heart can enlarge by stretching and thinning its walls which allows for it to increase output since amount of blood is increased.
• Increasing muscle mass. As thickness of muscle increases, the heart pumps with greater force to maintain cardiac output.
• Increase heart rate. This increase will increase the cardiac output.
• Increase blood pressure. The blood vessels narrow to keep blood pressure up to compensate for the loss in heart's force.
• Reroute blood. The body will decrease blood flow to less important tissues and organs to maintain normal flow to the most vital organs.

All of these compensations will disguise the heart failure condition and they will all eventually fail to solve the problem. These compensations will eventually cause an increased workload and pressure that will further contribute to the weakening of the heart.

Causes of CHF

The causes result usually from underlying conditions but there are also contributing factors to CHF.

Underlying Conditions:

• past heart attack (myocardial infarction)
• coronary artery disease
• high blood pressure (hypertension)
• valvular heart diseases
• Disease of the pericardium
• Diseases of the heart muscle (cardiomyopathy)
• Birth defects of the heart (congenital heart defects)
• infection of the heart valves and/or heart muscle itself — endocarditis and/or myocarditis.
• Abnormal heart rhythms (arrhythmias)
• Severe lung disease
• Diabetes
• Severe Anemia
• Hyperthyroidism

Contributing Factors:

The contributing factors that increase the risk of CHF are aging, smoking, stress, obesity, unhealthy diet, and lack of exercise.

Symptoms of CHF

• Shortness of breath (dyspnea)
• Coughing or wheezing
• Edema
• Weight gain
• Weakness and Fatigue
• Chest pain
• Lack of appetite and nausea
• Confusion and impaired thinking
• Increased heart rate

Diagnosing CHF

The common diagnostic tests are:

• Chest X-ray . It can detect the presence of an enlarged heart and congestion.
• Electrocardiogram (EKG). It can detect the presence of a previous heart attack, cardiac ischemia, abnormal heart rhythms or an enlarged heart.
• Echocardiogram. It can determine the ejection fraction which is amount of blood ejected from the heart with each heartbeat.

Treatment of CHF

CHF cannot be cured but it can be treated to improve the symptoms and prevent progression of CHF. The type of treatment options are improvement of lifestyle, medications, and surgery.

Lifestyle changes

The individual should exercise, eat healthy foods, quit smoking and drinking alcohol, lose weight, and reduce stress.

Medications
There are many different types of medications depending on the purpose of the medication and the type of heart failure the individual has. The goal of medications is to improve the individual's health by delaying the progression and improving symptoms. The drugs used include: diuretics, vasodilators, angiotensin receptor blockers, calcium channel blockers, alpha blockers, beta blockers, digitalis medications, and sympathomimetic medications.

Surgical procedures
Surgical procedures can also be used to treat CHF.

Underlying condition corrections through surgery:

• Heart valve replacement
• Congenital heart defect correction
• Coronary artery bypass

General treatment options through surgery:

• Devices that assist the severely failed heart (intra-aortic balloon pump, cardiac resynchronization therapy through bi-ventricular pacemaker, a left ventricular assist device, and implantable cardioverter-defibrillator)
• Heart transplants