1. Explain what stroke volume is and how it is related to the cardiovascular system; address, particularly, stroke volume, heart rate, and blood pressure.Stroke volume is defined as the amount of blood ejected from each ventricle with each contraction of the heart (VanMeter & Hubert, 2018). Together, heart rate and stroke volume dictate cardiac output (VanMeter & Hubert, 2018). Cardiac output is measured in liters per minute (Bruss & Raja, 2020). Blood pressure is the pressure of blood against arterial walls, and is dependent upon cardiac output (of which stroke volume is a part) and peripheral resistance (VanMeter & Hubert, 2018).
2. Identify two disorders of the cardiovascular system that affect stroke volume, heart rate, and BP, and explain how the disease state and pathophysiologic process alters these components away from their homeostatic state.One disorder of the cardiovascular system that affects stroke volume is congestive heart failure (CHF). CHF is caused by either a problem with the heart itself, increased demand on the heart, or a combination of factors (VanMeter & Hubert, 2018). When the heart cannot pump effectively, the body tries to compensate by increasing heart rate and blood pressure (VanMeter & Hubert, 2018). When the heart cannot pump effectively, in turn cardiac output and stroke volume decrease, which means that less blood reaches the organs and tissues (VanMeter & Hubert, 2018). This is how congestion of the heart occurs, because the inflow of blood to the heart exceeds the output.Another disorder of the cardiovascular system that effects stroke volume are valvular defects such as mitral valve prolapse. Mitral valve prolapse occurs when the pulmonary or aortic valves are large or misshapen and tend to billow backwards, which allows the regurgitation of blood (VanMeter & Hubert, 2018). This regurgitation decreases stroke volume and the overall performance of the heart (VanMeter & Hubert, 2018). 3. Describe how these changes can result in cardiac remodeling. What signs and symptoms do patients experience as this occurs?These changes result in cardiac remodeling which can include changes such as cavity diameter, mass of the heart, heart wall thickness and shape, scar tissue and fibrous changes (Azevedo et al., 2016). These changes result in ventricular dysfunction (Azevedo et al., 2016). Signs and symptoms of cardiac remodeling could be signs of heart failure such as increased edema and shortness of breath (VanMeter & Hubert, 2018).4. Discuss whether this remodeling is reversible and/or preventable. What can be done to correct the pathologic process and return the cardiovascular system to its homeostatic state.Cardiac remodeling is preventable by preventing chronic disease and risk factors that put stress on the heart. Some of these prevention tactics include smoking cessation, which is known to vasoconstrict and increase the overall workload of the heart (VanMeter & Hubert, 2018). Another component of this would be dietary changes and regular exercise to improve overall heart health. Things that can be done to correct the pathologic process of cardiac remodeling include establishing a cardiac rehab program that focuses on gradually increasing cardiac exercise, as well as diet and stress reduction. Additionally, cardiac medications work to restore the heart back to a homeostatic state. These medications include vasodilators such as nitroglycerin that decreases peripheral resistance and therefore decreases the workload of the heart (VanMeter & Hubert, 2018). Calcium channel blockers like amlodipine and verapamil decrease cardiac contractility. Diueretics such as furosemide decrease the workload of the heart by increasing urine output that then decreases overall blood volume, which decreases the workload on the heart (VanMeter & Hubert, 2018).*For my visual aid, I adapted a visual aid looking at cardiac remodeling, as I found it hard to find a visual or clear explanation of this. See attached. Also fair warning, I’m not an artist! *
Azevedo, P., Polegeto, B. Minicuccio, M., Paiva, S. & Zornhoff, L. (2016). Cardiac Remodeling: Concepts, Clinical Impact, Pathophysiological Mechanisms and Pharmacologic Treatment. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728597/Brass, Z. & Raja, A. (2020). Physiology: Stroke volume. Stat Pearls. https://www.ncbi.nlm.nih.gov/books/NBK547686/#article-29559.s4VanMeter, K. C., & Hubert, R. J. (2018). Gould’s pathophysiology for the health professions. (6th ed.). Elsevier Saunders.