Doctors usually classify patients' heart failure according to the severity of their symptoms. The table below describes the most commonly used classification system, the New York Heart Association (NYHA) Functional Classification. It places patients in one of four categories based on how much they are limited during physical activity.
Class How They Feel
- No symptoms and no limitation in ordinary physical activity.
- Mild symptoms and slight limitation during ordinary activity. Comfortable at rest.
- Marked limitation in activity due to symptoms, even during less-than-ordinary activity. Comfortable only at rest.
What is left-sided Heart Failure ?
Left-sided or left ventricular (LV) heart failure involves the heart's left ventricle (lower chamber). Oxygen-rich blood travels from the lungs to the left atrium, then on to the left ventricle, which pumps it to the rest of the body. Because this chamber supplies most of the heart's pumping power, it's larger than the others and essential for normal function.
If the left ventricle loses its ability to contract normally (called systolic failure), the heart can't pump with enough force to push enough blood into circulation. If the ventricle loses its ability to relax normally (diastolic failure) because the muscle has become stiff, the heart can't properly fill with blood during the resting period between each beat. This is an important distinction because the drug treatments for each type of failure are different.
In either case, blood coming into the left chamber from the lungs may "back up," causing fluid to leak into the lungs. (The technical term for this is pulmonary edema.) Also, as the heart's ability to pump decreases, blood flow slows down, causing fluid to build up in tissues throughout the body (edema). This excess fluid or congestion explains the term congestive heart failure, which you've probably heard before.
What is right-sided Heart Failure ?
The right atrium receives the "used" blood that returns to the heart through the veins; then the right ventricle pumps it into the lungs to be replenished with oxygen. Right-sided or right ventricular (RV) heart failure usually occurs as a result of left-sided failure. When the left ventricle fails, increased fluid pressure is, in effect, transferred back through the lungs, ultimately damaging the heart's right side. When the right side loses pumping power, blood backs up in the body's veins. This usually causes swelling in the legs and ankles.
