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Ch. 18 The Cardiovascular System: The Heart
Hoehn - Marieb Human Anatomy & Physiology, 12th edition
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
All textbooksHoehn, Haynes, Abbott 12th EditionCh. 18 The Cardiovascular System: The HeartProblem 24
Chapter 18, Problem 24

Florita Santos, a middle-aged woman, is admitted to the coronary care unit with a diagnosis of left ventricular failure resulting from a myocardial infarction. Her history indicates that she awoke in the middle of the night with severe chest pain. Her skin is pale and cold, and moist sounds are heard over the lower regions of both lungs. Explain how failure of the left ventricle can cause these signs and symptoms.

Verified step by step guidance
1
Understand the role of the left ventricle: The left ventricle is responsible for pumping oxygenated blood from the lungs into the systemic circulation, supplying the body with oxygen and nutrients.
Recognize what happens in left ventricular failure: When the left ventricle fails, it cannot effectively pump blood out to the body, causing blood to back up into the left atrium and then into the pulmonary veins and lungs.
Explain pulmonary congestion and edema: The increased pressure in the pulmonary circulation causes fluid to leak from the capillaries into the lung tissue and alveoli, leading to moist crackling sounds (rales) heard over the lower lungs and difficulty breathing.
Connect systemic effects: Because less blood is pumped into systemic circulation, tissues receive less oxygen, causing symptoms like pale, cold skin due to vasoconstriction and reduced peripheral perfusion.
Relate chest pain and myocardial infarction: The initial myocardial infarction damaged the heart muscle, impairing left ventricular function and triggering the cascade of symptoms described.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Left Ventricular Failure

Left ventricular failure occurs when the left ventricle cannot pump blood effectively, leading to reduced cardiac output. This causes blood to back up into the lungs, increasing pressure in pulmonary vessels and impairing oxygen exchange, which results in symptoms like shortness of breath and fluid accumulation.
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Pulmonary Congestion and Edema

When the left ventricle fails, blood accumulates in the pulmonary circulation, causing fluid to leak into lung tissues and air spaces. This pulmonary edema produces moist crackles on auscultation and contributes to respiratory distress, as seen in the moist lung sounds and difficulty breathing.
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Signs of Poor Perfusion in Heart Failure

Reduced cardiac output from left ventricular failure leads to inadequate blood flow to tissues, causing pale, cold, and clammy skin due to vasoconstriction and sympathetic activation. These signs reflect the body's attempt to maintain vital organ perfusion despite heart dysfunction.
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Related Practice
Textbook Question

You have been called upon to demonstrate the technique for listening to valve sounds.

Explain where you would position your stethoscope to auscultate.

(1) the aortic valve of a patient with severe aortic valve insufficiency and

(2) a stenotic mitral valve.

During which period(s) would you hear these abnormal valve sounds most clearly? (During atrial diastole, ventricular systole, ventricular diastole, or atrial systole?)

What cues would you use to differentiate between an insufficient and a stenotic valve?

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