The term "heart failure" can make it seem as though the entire heart is not functioning well. But heart failure refers to several different types of long-term heart problems that can affect distinct parts of the heart.
The heart is divided into two halves, the right and left sides. The right side pumps blood into the lungs to be oxygenated, after which it is returned to the left side of the heart to be pumped out to the rest of the body. Depending on the form of heart failure, left, right, or both sides of the heart can be affected.
The two main categories of heart failure are:
- Systolic heart failure -- the heart's pumping ability is reduced
- Diastolic heart failure -- the heart can still pump, but other things have gone wrong
Systolic heart failure
Heart failure with reduced pumping ability, called systolic heart failure, occurs when the left ventricle loses its normal squeezing power. As a result, the heart can pump out less than half its blood volume with each beat (called a reduced ejection fraction; normal is 55%-70%).
To make up for this loss of power, the heart will enlarge and beat faster in order to pump the normal amount of blood to the body. But over time, the heart weakens and eventually can't to keep up with the demands of the body by pumping enough blood out.
Diastolic heart failure
Diastolic heart failure occurs when the left ventricle is unable to properly relax due to muscle stiffening and thickening, which does not allow the heart to fill with enough blood between each beat. This leads to a shortage of blood being pumped out of the heart to meet the body's demands, even though the squeezing power of the heart is adequate.
Often, the inability of the heart to properly pump out the blood causes it to back up inside the lungs. This back pressure can contribute to shortness of breath due to fluid build-up in the lungs -- additional blood continues to flow into the heart, but not enough is leaving to make room, which forces fluid into the lungs.
Let's meet Mr. F, a 52-year-old restaurant owner:
Mr. F has a reduced ability to pump blood out of his left ventricle (called a reduced ejection fraction). Mr. F's heart failure is a type of systolic heart failure, where the left side of the heart can only pump 25% of blood inside the heart with every beat (normal is more than 55%). The most likely cause of Mr. F's heart failure is from a heart attack several years ago.
Mr. F's main challenge is that he needs to maintain a low blood pressure to keep extra strain off of his heart. He also has many of the classic symptoms of left-sided heart failure such as shortness of breath, leg swelling, and becoming tired easily.
Although Mr. F's heart failure resulted from a heart attack, there are many other causes that can lead to heart failure. The most common causes of heart failure are:
- Heart attacks or other forms of coronary artery disease -- narrowed arteries due to cholesterol build-up
- High blood pressure, or hypertension
- Rhythm problems of the heart leading to very rapid heart rates (like atrial fibrillation)
- Drug or alcohol misuse
- Genetic disorders of the heart that causing weakening of the heart muscle
- Certain kinds of chemotherapy agents
- HIV/AIDS or other infections
- Coronary artery disease- narrowed arteries due to plaque build-up.
There are often multiple signs and symptoms of heart that can build upon one another:
- Shortness of breath
- Swelling in the legs and ankles
- Excessive/easy fatigue
- Quick and sudden weight gain
- Persistent dry cough or wheezing
Heart failure treatment includes a combination of medications and healthy behaviors. Low sodium intake and a healthy diet are also critical. Additionally, while heart failure may prevent intensive exercise, physical activity is an important strategy.
Living with heart failure is difficult, but not impossible if the right steps are taken. There are many people with heart failure who live fruitful and active lives by combining the right medications with healthy lifestyle behaviors.
This is the third in a series of blog posts, Demystifying Heart Failure, to help patients and family members better understand and help mitigate heart failure. The next blog will explain the causes of heart failure.
Min Joo Kim is a master's degree student in Community Health and Prevention Research at Stanford studying the patient experience for those with chronic conditions and identifying barriers to treatment. Randall Stafford, MD, PhD, professor of medicine, focuses on strategies to improve chronic disease treatment, including engaging patients in their own health care.
Photo by Robina Weermeijer