Case Study - Valves S24_ JaylaBrown
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University of North Florida *
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2085C
Subject
Medicine
Date
Apr 3, 2024
Type
docx
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2
Uploaded by jalena022
A&P 2
Name & N#: A Case Study on Valve Function
Carl arrived at the ER suffering from severe shortness of breath (dyspnea) that began approximately 12 hours earlier. He was an active 64-year-old, with no recent illness or shortness of breath before today. He had a prior history of appendicitis, but was otherwise healthy, with no known cardiovascular issues or other chronic medical conditions. A chest X-ray showed some opacity of both lungs, but his heart was not enlarged. Additional tests ruled out a myocardial
infarction, but the doctor detected a noticeable murmur when listening to Carl’s heart. Carl was surprised to hear this, and reported that he had never been diagnosed with a heart murmur even though he had had regular physicals for the past 30 years. An echocardiogram (an ultrasound of the heart) showed that several of the chordae tendineae connected to the anterior leaflet of the left atrioventricular valve had ruptured. Use the following data to answer the questions below.
Heart rate: 102 bpm
End diastolic volume (EDV): 115 ml (within normal range)
End systolic volume (ESV): 30 ml (decreased)
Left ventricle size: normal
Left atrial size: normal Short Answer Questions
. Type or write your answers in the spaces below, changing the font for easier grading. Cite your sources.
1.
Explain how the ruptured chordae tendineae are related to the newly-detected murmur. The atrioventricular valves cannot open and enter the atria due to the chordae tendinae. Both an inadequate closure of the valve and blood leakage into the atrium may be caused by a ruptured chordae tendineae attached to the anterior leaflet of the
left atrioventricular valve. This is the source of the murmur as well as the inefficient and aberrant blood flow that follows. (Section 19.4 pg 214)
2.
Consider the path blood now takes during contraction of Carl’s left ventricle and the influence of afterload. Why is his ESV less than normal? The aortic valve opens to allow blood to flow freely into the aorta, enabling the left ventricle to pump oxygenated blood into it with ease in a healthy, normal heart. However, the left ventricle encounters more resistance during contraction when someone like Carl has a ruptured chordae tendineae, which makes it more difficult for the heart to pump blood into the aorta. As a result, the left ventricle has less blood at
the end of systole than it would in a healthy heart, resulting in a decreased End-
Systolic Volume. Because the left ventricle must overcome less resistance to expel blood, the reduction in blood volume results in less effort on its part. (
Section 19.3 pg
214
).
A&P 2
Name & N#: 3.
Why is Carl’s heart rate elevated? The left ventricle will probably swell in Carl's case due to the chordae tendineae rupture. This could happen as a result of the mitral (bicuspid) valve failing, which can cause blood to overflow into the left atrium when the valve doesn't seal correctly during contraction of the left ventricle. The left ventricle has to work harder to pump out the extra blood as a result of the blood buildup, which raises the pressure inside the chamber. In the end, this may cause the left ventricle to expand.
4.
Without treatment, this condition will result in enlargement of Carl’s left ventricle. Why is this the case, and what consequence(s) would this have on his cardiovascular health?
The left ventricle will probably swell in Carl's case due to the chordae tendineae rupture. This could happen as a result of the mitral (bicuspid) valve failing, which can cause blood to overflow into the left atrium when the valve doesn't seal correctly during contraction of the left ventricle. The left ventricle has to work harder to pump out the extra blood as a result of the blood buildup, which raises the pressure inside the chamber. In the end, this may cause the left ventricle to expand.
5.
Tests ruled out a myocardial infarction for Carl. What is a myocardial infarction? What type of test could determine if this is what he was experiencing?
A myocardial infarction, also called a heart attack, is a condition resulting from sudden and complete occlusion of an coronary artery (Section 19.5 pg 216
). This happens when oxygen deprivation results from inadequate oxygen delivery to the heart muscle by the coronary circulation, which is in charge of supplying oxygen to the heart. Diagnostic procedures like an electrocardiogram (ECG/EKG) and blood tests
can identify the effects of this by determining whether a person has had a heart attack. An ECG displays the data as electrical waves and detects the heart's total electrical activity, which includes contractile and pacemaker cells.
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