To understand heart failure, it helps to understand how the heart works.
The heart is a muscle that pumps blood. The “used” blood that returns from the body in the veins is low in oxygen. It passes first through the upper chamber on the right side, (1) called the right atrium, and is then pumped to the lungs by the lower chamber on the right, (2) called the right ventricle.
The lungs put oxygen back in the blood which is returned to the upper chamber on the left, (3) called the left atrium, and then to the lower chamber on the left, (4) called the left ventricle.
The left ventricle pumps the blood out through the aorta (5), to the rest of the body…then it goes around again and again.
There are four valves in the heart that open to let blood go forward, then close to prevent blood from being pushed back to where it just came from. Electrical signals tell the different parts of the heart when to beat so everything works together to pump the blood.
The heart has its own supply of blood to get the oxygen and other nutrients it needs to do its work. The blood is carried through small vessels called coronary arteries. These arteries may become blocked with cholesterol and other materials, causing a “heart attack” in which a portion of the heart muscle supplied by that artery dies.
Heart failure is diagnosed when the heart can’t pump enough blood to keep up with the body’s needs. This generally causes fluid to build up in the body, and is often associated with being tired, short of breath or not able to do as many activities.
There are two main types of heart failure. The first type is known as systolic heart failure. The heart’s ability to contract (squeeze) decreases and the left ventricle of the heart does not pump out all of the blood in its chambers when it contracts. It usually pumps out a little more than half, around 55 percent.
The second type of heart failure is diastolic failure, where the heart is thick and stiff. The heart may pump out all of the blood when it contracts, but can resist filling with blood because it can’t relax.
There are many causes of heart failure. The most common is from damage to the muscle caused by heart attacks. The next most common cause is a long history of high blood pressure. Drinking too much alcohol for a long time can also cause heart muscle damage. In a surprising number of cases, doctors are not able to find a cause.
The following symptoms can be signs of heart failure:
- Running out of energy easily
- Shortness of breath — with routine activities, that wakes you from sleep, or when lying down
- Puffy, swollen legs, ankles or feet
- Poor appetite or nausea
- A dry, nagging cough
- Rapid weight gain — three pounds or more in a day; five pounds or more in a week