CHF is congested heart failure. Usually the heart has weak contractions and able to only pump something less than 29% of blood received form the lungs. This causes blood to backup in the lungs and fluid leaks into the lung tissues medically referred to as lung edema (congestion).
In the heart affected by cardiomyopathy, heart muscle cells are damaged so that it contracts poorly. The hearts overall systolic (pumping) function is therefore impaired. In an attempt to compensate for its reduced ability to pump, the heart muscle hypertrophies (thickens) and the hearts chambers enlarge. In association with the process of hypertrophy, scar tissue proliferates and infiltrates the heart muscle so that arrhythmias may develop.