What is congestive heart failure?

Weakened heart: A normal heart will eject (ef) about 60% of blood from main chamber (left ventricle) out aorta and feeds entire body with oxygenated blood. When this muscle chamber, size of fist, develops weakness of some of it's walls (heart attack, eg) or is constricted (pericarditis) etc, then it starts failing, ef decreases, backup pressure develops, fluid builds up in lungs or legs and CHF has occurred.

CHF: CHF is when the heart is not pumping the blood adequately out of the heart into the aorta and the blood backs up causing the lungs to fill with fluid due to the increase in hydrostatic pressures. For class iii or class IV CHF - eecp is recommended.

CHF: is exactly what is says it is. You usually have congestion in the chest caused by blood/fluid backing up in your lung. And that is because the patient has a failing heart - either because it has a very weak muscle like in systolic heart failure when the ejection fraction