C155 v1.docx - C155 FOUNDATIONS FOR ADVANCED NURSING PRACTICE C155 Western Governors University C155 FOUNDATIONS 2 Heart Failure Heart failure as

C155 v1.docx - C155 FOUNDATIONS FOR ADVANCED NURSING...

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C155 PATHOPHARMACOLOGICAL FOUNDATIONS FOR ADVANCED NURSING PRACTICE C155 Western Governors University May 23, 2018
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C155 PATHOPHARMACOLOGICAL FOUNDATIONS 2 Heart Failure Heart failure, as defined by the American Heart Association (AHA), is a condition in which the heart is no longer able to pump blood efficiently (What is Heart Failure, n.d.). It affects an estimated 26 million people across the globe (Aguanno & Samson, 2017). There can be several reasons for someone developing heart failure, from improperly working heart valves, to a myocardial infarction (MI), or “heart attack”, that can leave the heart muscle weakened. There are four different classifications of heart failure, from class 1, which may or may not cause any symptoms, and only minimally inhibits normal daily activities, to class 4, which causes significant outward symptoms and severely limits a person’s ability to be active (What is Heart Failure, n.d.). Pathophysiology of the Disease Process The progression of this disease begins when the heart is unable to keep up with the demand put on it by an increased need for oxygen and blood to the rest of the body. To make up for this deficient heart strength, the muscle fibers of the heart stretch to provide a stronger contraction, which will pump more blood with each beat. Just like when any muscle is stretched again and again, over time, it gets bigger. Because the heart is a muscle, this exercise enlarges the heart. A larger heart can pump stronger, at least at first. As the heart muscle continues to stretch, it becomes weaker and less efficient. Eventually, the weakened heart can’t stretch its fibers to become any larger and a weak, stretched out heart muscle can’t squeeze as well, so less blood is pumped out of the ventricles into the body. Less blood being pumped out of the heart leads to the body trying to preserve the most important organs, the heart and the brain. It does this by diverting blood from other non-essential organs. When this diversion occurs, those organs will begin to function poorly and eventually fail as well. This weak heart continues to get weaker over time, and this reduces the cardiac output even further. Eventually, the heart won’t be able to pump enough blood to perfuse even itself and the brain. If this person has not yet died from the
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C155 PATHOPHARMACOLOGICAL FOUNDATIONS 3 multi-system organ failure caused by heart failure, they will probably succumb soon after this point. While the heart is compensating for its inefficient pumping by enlarging its muscle fibers, it may also try to compensate by increasing the rate at which it beats. This is an effort by the heart to increase the amount of blood pumped out per minute, rather than by heartbeat. During a normal heartbeat, the valves within the heart open and close in concert with each other to allow the chambers of the heart to fill and empty appropriately. With a faster heartbeat, these valves no longer have enough time to allow the heart chambers fill and empty appropriately. This leads to not enough blood being ejected into the body with each beat. This cascade of events leads to the
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