Patient information: Heart failure causes, symptoms, and diagnosis

HEART FAILURE OVERVIEW

Heart failure causes weakening of the heart, which limits the ability of the heart to pump. The name "heart failure" can be misleading, because the heart does not completely fail or stop, but instead it functions less effectively. Heart failure (HF) may range in severity; it can be a mild condition that causes almost no symptoms. In other people with heart failure, the heart is significantly damaged, causing fatigue, shortness of breath and ankle swelling.

Heart failure itself is not a disease, but rather, a syndrome that develops as other conditions damage the heart. Sometimes it develops quickly, over days to weeks. In most cases, heart failure develops slowly, as the heart gradually weakens and has difficulty keeping up with its workload. Although heart failure is a serious condition, much can be done to manage its effects and its impact.

It is estimated that, in the United States, almost five million people have heart failure and over 600,000 people develop heart failure each year.

This article discusses the causes, symptoms, and diagnosis of heart failure. A separate article discusses treatment options for people with heart failure. (See "Patient information: Heart failure treatments".) More detailed information about heart failure is available by subscription. (See "Evaluation of the patient with suspected heart failure".)

THE HEART

The heart is composed of four chambers: the two upper chambers are the right and left atria and the two lower chambers are the right and left ventricles (figure 1). The left ventricle is important because it works to pump blood out to the entire body.

Types of heart failure — Patients with heart failure typically have a condition that has damaged the heart muscle.

• Systolic dysfunction is a type of heart failure that occurs when the left ventricle is weakened, making if harder for the ventricle to pump blood out to the rest of the body.
• Diastolic dysfunction is a type of heart failure that occurs when the left ventricle becomes stiff (it does not relax normally) so that the heart has difficulty filling with blood. As a result, the heart can pump less blood, and the heart cannot adapt and work harder when needed.

HEART FAILURE CAUSES

Heart failure results from other diseases and conditions that damage the heart. If untreated, any one of these conditions can damage the heart and lead to heart failure. Having more than one condition increases the risk of heart failure even further.

Fortunately, treating these conditions during their early stages can often prevent heart failure or significantly delay its onset. In order for a prevention strategy to work, however, the condition must be diagnosed early and treated effectively. These conditions include:

High blood pressure (hypertension) — In high blood pressure, the heart must work harder to pump blood against increased pressure in the body's network of veins. This increased workload can, over time, lead to an enlarged and poorly functioning heart. (See "Patient information: High blood pressure in adults".)

Coronary heart disease — In this condition, the blood vessels that "feed" the heart muscle are narrowed and blood flow through them is reduced. As a result, portions of the heart muscle are deprived of oxygen (especially during exercise, when the body needs more blood supply and oxygen) and the heart does not perform its work as well.

Coronary heart disease can lead to a heart attack (also called a myocardial infarction), which causes permanent damage to the heart muscle. In some cases, when large portions of heart muscle are damaged by a heart attack, heart failure can develop. (See "Patient information: Heart attack".)

Damage to the heart valves — A number of conditions, including heart attack, high blood pressure, and aging, can damage the heart valves. As a result of this damage, the normal forward flow of blood through the heart is disrupted. In some cases the valve becomes narrowed (stenotic), causing an increased pressure within the heart. In other cases the valve becomes leaky (or insufficient), causing blood to flow backward (regurgitation). (See "Patient information: Mitral regurgitation".)

Cardiomyopathy — In cardiomyopathy, the heart muscle has been damaged, leading to an enlarged, poorly pumping heart. (See "Patient information: Dilated cardiomyopathy".)

Diabetes — In some cases, diabetes causes damage to the heart muscle, increasing the likelihood that heart failure will develop. In addition, people with diabetes who also have other risk factors for coronary artery disease (eg, smoking) probably have an increased risk for developing heart failure.

HEART FAILURE SYMPTOMS

As the amount of blood pumped by the heart (the cardiac output) decreases, a variety of symptoms can develop.

• Weakness, lightheadedness, or dizziness
• Shortness of breath, which may require you to sleep with several pillows
• A rapid heart rate, even while resting
• Swelling in the lower legs and feet (edema) or in the abdomen (ascites) (see "Patient information: Edema (swelling)".
• Feeling tired quickly

HEART FAILURE DIAGNOSIS

Heart failure is diagnosed based upon your medical history, physical examination, and a series of tests.

Diagnostic tests help to evaluate how the heart is performing and can help to identify conditions that caused the heart failure. Once treatment has begun, some tests may be repeated to see how well the treatment is working. Tests may include:

Chest x-ray — A chest x-ray shows the size and shape of the heart and the large blood vessels in the chest. It also can show if there is fluid in the lungs.

Electrocardiogram (EKG) — An EKG provides a picture of the electrical activity that causes the heart to beat. An EKG may detect conditions such as an abnormal heart rhythm or a previous heart attack that could cause heart failure.

Echocardiogram — An echocardiogram uses ultrasound (high frequency sound waves) to assess the size of the heart's chambers, and the movement of the heart valves. This test can also measure how much blood your heart is pumping with each heartbeat. A follow-up echocardiogram can be done to see if your heart function changes over time.

Exercise testing — An exercise test ("stress test") determines how well your heart performs during exercise. It is one way to look for signs of a shortage of blood supply to your heart caused by blockages in the coronary arteries. A doctor or nurse will see how your heart rsponds to exercise by looking at the ECG, blood pressure, and heart rate as you walk on a treadmill. In addition, pictures may be taken to measure the effect of exercise on the heart.

Heart (cardiac) catheterization — Cardiac catheterization helps measure how well the heart is functioning and provides pictures of the coronary arteries to look for blockages.

During the test, a thin tube (the catheter) is inserted through a large blood vessel in the groin (or arm) and advanced into the heart. A dye is injected into the catheter to view the arteries and the structure of the heart by x-ray.

Noninvasive imaging — Cardiac catheterization is an invasive test that can have risks. As a result, noninvasive imaging tests, like computed tomography (CT) or magnetic resonance imaging (MRI) are sometimes used as an alternative option to evaluate the coronary arteries and blood flow through the heart.

A noninvasive imaging test is not recommended in every situation, but may be an option for some people with heart failure.

HEART FAILURE TREATMENT

Because the cause and severity of heart failure is different in everyone, treatment is individualized based upon your situation. In general, the treatment of heart failure focuses on two goals: correcting or slowing conditions that led to heart failure and managing the weakened heart function. A separate article discusses the treatment on heart failure. (See "Patient information: Heart failure treatments".)

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: Heart failure treatments
Patient information: High blood pressure in adults
Patient information: Heart attack
Patient information: Mitral regurgitation
Patient information: Dilated cardiomyopathy
Patient information: Edema (swelling)

Professional Level Information:
Clinical manifestations and diagnosis of diastolic heart failure
Epidemiology and causes of heart failure
Evaluation and management of asymptomatic left ventricular systolic dysfunction
Evaluation of the patient with suspected heart failure
Overview of the therapy of heart failure due to systolic dysfunction
Prognosis of heart failure
Treatment and prognosis of diastolic heart failure

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• National Heart, Lung, and Blood Institute

      (www.nhlbi.nih.gov)

• American Heart Association

      (www.americanheart.org)

• Heart Failure Online

     (www.heartfailure.org, also available in Spanish)

• European Society of Cardiology

      (www.escardio.org)

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