Your heart is a muscle with two upper chambers (atria) and two lower chambers (ventricles). These heart chambers squeeze and expand in a precise sequence to push blood to your body and lungs. The blood your heart pushes to your body carries vital oxygen and nutrients to your body’s tissues and organs. The blood that is pushed to the lungs picks up oxygen in the lungs and then returns to the heart to be pumped out to the body to provide oxygen and nutrients to the tissues.
In heart failure, either the left or right ventricle, or both, may lose their ability to effectively pump blood. One way this is determined is through a measurement called the ejection fraction, which is the percentage of blood the heart’s ventricles push out of the heart. Even a healthy ventricle does not pump out 100 percent of the blood. Like any pump that pumps fluid, some fluid remains behind to “prime” the pump. A normal heart may have an ejection fraction between 55 and 70 percent.
The left ventricle is the main pumping chamber of the heart and pumps blood to the body. The right ventricle pumps blood to the lungs to pick up oxygen. In most cases, the left ventricle is the first chamber to fail.
Failure of the left side of the heart can be described as systolic or diastolic. In systolic heart failure, the heart’s left ventricle is weak and cannot push out enough blood to the body during systole, or when the chamber contracts. In diastolic heart failure, the passive and active processes to fill the heart with blood for the next pumping cycle is impaired. In many cases, heart failure can be a combination of systolic and diastolic problems.
What Is Congestive Heart Failure (CHF)?
You may have heard the term congestive heart failure. When the heart cannot pump and fill efficiently, it can cause blood to back up into the lungs, creating fluid build-up. Since the kidneys are very sensitive and require good blood flow to them, when they are impaired, enough urine cannot be made. This can cause an imbalance of fluids in the body, extra fluid build-up or “congestion,” which can result in swelling in the tissues such as in the legs, a persistent cough, or difficulty in breathing.
While there are many causes of heart failure, the condition can be described by two basic categories:
- Ischemic heart failure is caused by blocked blood flow, and
- Nonischemic heart failure is caused by problems other than blocked blood flow.
To learn more about ischemic and nonischemic heart failure, visit Types of Heart Failure.
Classifying Heart Failure
A treating physician will classify the severity of heart failure based on test results (an “objective” assessment) and the symptoms reported by the patient. The most commonly used heart failure classification system is the New York Heart Association (NYHA) Functional Classification. This table may help you understand how a physician will assess heart failure in a patient.
To better understand heart failure, it may be helpful to gain a general understanding of how a healthy heart and blood vessels function.
After heart failure causes have been identified (when possible), treatment will begin. Heart failure treatment most often takes a management approach. There is no cure for most cases of heart failure, but carefully managing or eliminating risk factors and causes can improve quality and extend length of life.