NUR 239 Lecture Notes - Lecture 17: Ejection Fraction, Heart Valve, Cardiac Output
21 May 2018
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NUR 239/Pathophysiology and Pharmacotherapeutics in Nursing I
Unit 3/Porth Chapter 20 Heart Failure and Circulatory Shock
Complete the following study guide and submit on Reggie Net by the due date on the Course Calendar
1
Porth Chapter 20 – Heat Failure and Circulatory Shock
Define the following terms:
▪ Cardiac Reserve: ability of the hart to increase its output during increased activity
▪ Ejection fraction: fraction of the end-diastolic volume that is ejected (60% in a healthy person)
▪ Cardiac output: major determinant of cardiac performance, reflects how often the heart beats
each minute (HR) and how much blood it ejects with each beat (SV)
▪ Preload: reflects the volume of blood that stretches the ventricle at the end of diastole, just before
the onset of systole
▪ End-diastolic volume: preload increases the length of the myocardial muscle fibers
▪ Afterload: represents the force that the contracting heart muscle must generate to eject blood
from the filled ventricles
▪ Inotropy: myocardial contractility, refers to the contractile performance of the heart or the ability
of the contractile elements of the heart muscle to interact and shorten against a load
▪ Cardiac glycosides: various forms of digitalis (treatment for HF), improving cardiac function by
increasing the force and strength of ventricular contractions
▪ Circulatory Failure: an acute failure to supply the peripheral tissues and organs of the body with
an adequate blood supply resulting in cellular hypoxia
▪ Anaphylactic Shock: results from an immunologically mediated reaction in which vasodilator
substances such as histamine are released in the blood
Key Learning Objectives - Answer the follow questions (Porth Chapter 20)
▪ Heart failure is a complex syndrome. List the possible disorders that may result in this condition
and determine if the disorder is structural or functional and if it impacts filling of the ventricle
(preload) or ejection of blood from the ventricle (afterload).
Both structural and function impairments of ventricular filling or ejection of blood into the
circulation. Possible disorder that may result are of the pericardium, myocardium, endocardium,
cardiac valves, or great vessels, or from metabolic abnormalities.
▪ In the section Pathophysiology of Heart Failure, what factors determine the efficiency of the
heart (pump)?
Determined by the volume of blood that it ejects each minute. The amount ejected is dependent
upon the ability of the ventricles to relax and fill.
▪ Heart rate is controlled by a balance between what Autonomic Nervous System elements.
Explain how each side works.
o Parasympathetic: relaxes and slows high energy function of the SNS
find more resources at oneclass.com
find more resources at oneclass.com
NUR 239/Pathophysiology and Pharmacotherapeutics in Nursing I
Unit 3/Porth Chapter 20 Heart Failure and Circulatory Shock
Complete the following study guide and submit on Reggie Net by the due date on the Course Calendar
2
o Sympathetic: maintain BP and CO, but can deteriorate heart function through
tachycardia, vasoconstriction, and cardiac arrhythmias
▪ Briefly explain the Renin-Angiotensin-Aldosterone Mechanism. How does a decrease in cardiac
output affect kidney function? How does decreased renal function impact a heart failure patient?
CO is a reduction in renal blood flow and glomerular filtration rate which leads to sodium and
water retention. With decreased renal blood flow, there is an increase in renin secretion by the
kidneys with parallel increased in circulating levels of angiotensin II. Angiotensin II relates to
the excessive vasoconstriction and a powerful stimulus for aldosterone production by the adrenal
cortex. Aldosterone increases tubular reabsorption of sodium with increase in water retention.
Because aldosterone is metabolized in the liver, its level further increased when HF causes liver
congestion.
▪ Describe how myocardial hypertrophy and remodeling compensates for increased workload of
the heart. What are the structure changes and cardiac function that result?
Hypertrophy increases change in structure of the muscle mass or chamber dilation, and cardiac
function such as impaired systolic or diastolic function that lead to further pump dysfunction and
hemodynamic overload.
▪ Define and give an example of each type of ventricular hypertrophy: symmetric hypertrophy,
concentric hypertrophy, and eccentric hypertrophy.
Symmetric hypertrophy: stimuli with a proportionate increase in muscle length and width, like in
athletes
Concentric hypertrophy: increase in wall thickness, like in HTN
Eccentric hypertrophy: disproportionate increase in muscle length, like in dilated
cardiomyopathy
▪ Describe the classifications of Heart Failure.
ejection fraction (reduced or preserved) or as left-sided or right-sided failure. HF with a reduced
ejection fraction is defined as the inability of the ventricle to eject an adequate cardiac output
despite a normal blood pressure. HF with a preserved ejection fraction is characterized by a
normal of normal EF and abnormal diastolic function. Persons with a reduced or preserved
ejection fraction may be symptomatic or asymptomatic. In order to be diagnosed with HG, they
must also exhibit signs and symptoms such SOB, decreased exercise tolerance, and orthopnea
(SOB when lying down).
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Porth chapter 20 heat failure and circulatory shock. Key learning objectives - answer the follow questions (porth chapter 20: heart failure is a complex syndrome. List the possible disorders that may result in this condition and determine if the disorder is structural or functional and if it impacts filling of the ventricle (preload) or ejection of blood from the ventricle (afterload). Both structural and function impairments of ventricular filling or ejection of blood into the circulation. Possible disorder that may result are of the pericardium, myocardium, endocardium, cardiac valves, or great vessels, or from metabolic abnormalities. Determined by the volume of blood that it ejects each minute. The amount ejected is dependent upon the ability of the ventricles to relax and fill: heart rate is controlled by a balance between what autonomic nervous system elements. Explain how each side works: parasympathetic: relaxes and slows high energy function of the sns.
