Congestive heart failure (CHF) is a term used when the pumping action of the heart becomes increasingly less powerful and effective over a period of time. When this happens, blood does not move efficiently through the circulatory system and starts to back up, increasing pressure and causing fluid to leak from the capillary blood vessels. The left ventricle is usually the first to fail because it works harder to pump blood to the entire body, but it can also mask right ventricle failure. The American College of Cardiology/American Heart Association developed the following objective classification for stages of CHF:
Stage A: No objective evidence of cardiovascular disease. No symptoms and no limitation in ordinary physical activity.
Stage B: Objective evidence of minimal cardiovascular disease. Mild symptoms and slight limitation during ordinary activity. Comfortable at rest.
Stage C: Objective evidence of moderately severe cardiovascular disease. Marked limitation in activity due to symptoms, even during less-than-ordinary activity. Comfortable only at rest.
Stage D: Objective evidence of severe cardiovascular disease. Severe limitations. Experiences symptoms even while at rest.
CHF is caused by conditions that damage the heart muscle including coronary artery disease, heart attack, cardiomyopathy, high blood pressure, valve disease, thyroid disease, kidney disease, diabetes, or congenital heart defects present at birth.
Congenital Heart Defects (CHDs) are the most common type of birth defect, accounting for nearly one-third of all major congenital anomalies. In an article published in the November 2011 issue of the Journal of the American College of Cardiology, the authors cited a worldwide study population of 24,091,867 live births, with CHD identified in 164,396 individuals. In infants, CHDs may lead to transplantation when surgical interventions and other treatments fail. Pediatric cardiothoracic surgeons generally perform heart transplants in children with CHDs from infancy to age 7 or 8. Mechanical heart devices are a far more recent development in children than in adults due to challenges posed by the size of the heart as well as the anatomical defects, for example, being born with a single ventricle.