The heart is quite an amazing biological pump. It beats every second of every day of your life. As with just about anything, it can wear out over time. When this happens, a person will begin to go in to heart failure. This simply means that the heart is no longer able to push the necessary amount of blood through the chambers of the heart and to the lungs or the rest of the body.
The heart is divided in to two primary "sides" - right and left. Very simply, the right side of the heart consists of the right atrium and the right ventricle. These two chambers work together to receive blood which is returning from the body and pump it to the lungs where it can be "recharged" with oxygen.
The left side of the heart has the left atrium and left ventricle. The left atrium receives blood from the lungs and pumps it to the left ventricle. The left ventricle then gives the blood a final, massive push to send it circulating around the body.
Either one or both sides of the heart can fail. The symptoms which are produced by heart failure are largely dependent on which side of the heart is failing. Let's take a look at heart failure for each side individually.
Before moving on to the symptoms, I'll take a moment to note that heart failure is an incredibly complex topic. There are literally dozens of causes of heart failure. This article is only scratches the surface of what is a massive topic and set of diseases.
Left sided heart failure
Left sided heart failure results when the left ventricle is unable to push a proper amount of blood in to the aorta and subsequently throughout the body. Blood "pools" in the left side of the heart and causes a backup in the plumbing.
Common symptoms include shortness of breath (especially when exercising), fatigue, a chronic cough, and shortness of breath when lying down (known as orthopnea). Oftentimes the lungs are heavily involved in left heart failure. As the left side of the heart is unable to pump, blood returning to the left side from the lungs is not able to move properly. This causes a buildup of fluid in the lungs, and many of the symptoms of left heart failure.
Right sided heart failure
Right sided heart failure has a somewhat different set of symptoms. It is important to note that one of the more common causes of right sided heart failure is left sided failure. Consequently, it is possible for a person to suffer from both, especially in advanced stages of the diseases.
Right sided heart failure can causes swelling, especially in the lower legs. Fluid in the abdomen (called ascites) is common. Nausea, loss of appetite, and pain in the abdomen are common as well. People often complain of a racing heart, cold extremities, and excessive sweating.
In addition to these symtoms for both left and right sided failure, there are a wide range of signs that a doctor can pick up on. Left sided failure will cause changes in the heart sounds and lung sounds. Right sided failure will cause enlargement of the liver, which a doctor can feel. These are not the only signs, but are somewhat common.
Again, this is not meant to be a comprehensive review of the topic. For more information about heart failure and it's related symptoms, have a talk with your doctor. This is a complex topic and understanding all of the nuances can be quite an educational experience.