Heart failure is almost always a chronic, long-term condition, although it can sometimes develop suddenly. This condition may affect the right side, the left side, or both sides of the heart.
As the heart's pumping action is lost, blood may back up into other areas of the body, including the :
· Gastrointestinal tract, arms, and legs (right-sided heart failure)
· Liver
· Lungs (left-sided heart failure)
Heart failure results in a lack of oxygen and nutrition to organs, which damages them and reduces their ability to function properly. Most areas of the body can be affected when both sides of the heart fail.
The most common causes of heart failure are :
· Coronary artery disease
· High blood pressure
Other structural or functional causes of heart failure include :
· Cardiomyopathy
1. Dilated cardiomyopathy
2. Hypertropic cardiomyopathy
3. Restrictive cardiomyopathy
· Congenital heart disease
· Heart valve disease
· Heart tumor
· Lung disease
Heart failure becomes more common with advancing age. You are also at increased risk for developing heart failure if you are overweight, have diabetes, smoke cigarettes, abuse alcohol, or use cocaine.
CHF is summarized best as an imbalance in Starling forces or an imbalance in the degree of end-diastolic fiber stretch proportional to the systolic mechanical work expended in an ensuing contraction. This imbalance may be characterized as a malfunction between the mechanisms that keep the interstitium and alveoli dry and the opposing forces that are responsible for fluid transfer to the interstitium.
Maintenance of plasma oncotic pressure (generally about 25 mm Hg) higher than pulmonary capillary pressure (about 7-12 mm Hg), maintenance of connective tissue and cellular barriers relatively impermeable to plasma proteins, and maintenance of an extensive lymphatic system are the mechanisms that keep the interstitium and alveoli dry.
Opposing forces responsible for fluid transfer to the interstitium include pulmonary capillary pressure and plasma oncotic pressure. Under normal circumstances, when fluid is transferred into the lung interstitium with increased lymphatic flow, no increase in interstitial volume occurs. However, when the capacity of lymphatic drainage is exceeded, liquid accumulates in the interstitial spaces surrounding the bronchioles and lung vasculature, thus creating CHF. When increased fluid and pressure cause tracking into the interstitial space around the alveoli and disruption of alveolar membrane junctions, fluid floods the alveoli and leads to pulmonary edema.
