Heart Failure
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Heart failure is an abnormal condition of the heart’s ability to pump blood to meet the metabolic needs of the tissues and results from multiple health problems or risk factors. In this chapter we look at the pathology of heart failure and the severe clinical manifestations that result from it. Treatment and nursing implications are also discussed.
CAUSES OF HEART FAILUREHeart failure is an abnormal condition of the heart’s ability to pump blood to meet the metabolic needs of the tissues. Heart failure results from multiple health problems or risk factors, including obesity and elevated cholesterol levels, that lead to coronary artery disease. Long-term diabetes mellitus causes severe damage to the vascular system and causes a predisposition to heart failure. Heart failure frequently occurs secondary to damaged cardiac muscle. Myocardial infarction, ventricular aneurysm, and myocarditis are problems that affect the contractility of the heart. Ventricular overload, which is the result of increased blood return to the heart, may also result in congestive heart failure. Most commonly, heart failure results from hypertension associated with atherosclerosis of the heart and blood vessels from sustained elevated high blood pressure levels. Whatever the cause, heart failure results in an increased workload for the ventricles. The increased workload of the heart eventually causes both the right and left ventricles to fail and improperly supply the body with oxygenated blood.
Heart failure results in an increased workload for the ventricles. The increased workload of the heart eventually causes both the right and left ventricles to fail and improperly supply the body with oxygenated blood.Numerous terms have been used to further describe heart failure, including forward and backward heart failure, low- and high-output failure, systolic and diastolic dysfunction (Figure 46-1), right-sided and left-sided failure, or congestive heart failure, a more precise term when circulatory or pulmonary congestion is present. Currently, systolic and diastolic and right-sided and left-sided are the commonly used terms to describe heart failure. Regardless of the description used to identify heart failure, as the disease progresses into a chronic condition the terms no longer seem different and tend to blend together. Emerging symptoms and system deterioration ultimately lead to a diminished quality of life and shortened life expectancy.
PATHOLOGYSystolic Failure
Systolic failure occurs when the left ventricle (systolic function) is affected by an event that affects the contractility of the cardiac muscle fibers, making the left ventricle unable to pump the blood effectively and
empty completely. Attempts to pump blood from the left ventricle against the high pressured aorta fail, decreasing the left ventricular ejection fraction (the amount of blood ejected from the heart per beat, taking into consideration the entire amount of blood available per beat) and leaving blood in the ventricle, which increases the left ventricular end-diastolic pressure. During subsequent cardiac cycles, the regular amount of blood is propelled from the right ventricle to the lungs to the left atrium and into the left ventricle. Already filled with blood from the previous cycle, the left ventricle cannot accept the quantity prepared for it. Eventually, blood accumulates in the pulmonary circulation, elevating the pulmonary capillary wedge pressure. Systolic failure is associated with dilated cardiomyopathy and ischemic cardiomyopathy, along with other disorders.
empty completely. Attempts to pump blood from the left ventricle against the high pressured aorta fail, decreasing the left ventricular ejection fraction (the amount of blood ejected from the heart per beat, taking into consideration the entire amount of blood available per beat) and leaving blood in the ventricle, which increases the left ventricular end-diastolic pressure. During subsequent cardiac cycles, the regular amount of blood is propelled from the right ventricle to the lungs to the left atrium and into the left ventricle. Already filled with blood from the previous cycle, the left ventricle cannot accept the quantity prepared for it. Eventually, blood accumulates in the pulmonary circulation, elevating the pulmonary capillary wedge pressure. Systolic failure is associated with dilated cardiomyopathy and ischemic cardiomyopathy, along with other disorders.
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