Understanding the pathophysiology of a myocardial infarction begins with atherosclerosis, the main contributor to MI. “Atherosclerosis a common disorder characterized by yellowish plaques of cholesterol, other lipids, and cellular debris in the inner layers of the walls of arteries (Mosby, 2013, pg.153).” Fatty deposits (lipids) are circulating through the blood and become stuck to the artery walls, due to an injury in the endothelial lining of the blood vessel. After some time, the build up of plaque activates the body’s inflammatory process. Macrophages are sent to clean up the debris however if there is a high amount of lipids, the macrophages become enlarged and are not able to leak through the capillary bed via vascular permeability.
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Hypertension is a consistent increase of systemic arterial blood pressure, which is influenced by cardiac output and peripheral vascular resistance. The equation for cardiac output is stroke volume (liters per heart beat) multiplied by heart rate (beats per minute). Peripheral vascular resistance is the opposition to the flow of blood that the heart must overcome, which can increase due to an occlusion or vessel edema. With hypertension, cardiac output and stroke volume decreases as heart rate and peripheral resistance increases due to overcompensation of the heart (Huether & McCance 2012). When the heart beats, it propels blood through the arteries to increase circulation throughout your entire body. Higher blood pressures mean that with each beat, arteries throughout the body swell and stretch more than they would normally. Stretching of the endothelium, the delicate lining of all arteries, can cause injury and result in arteries becoming stiffer over time. Healthy endothelium actively works to prevent atherosclerosis from developing. Injured endothelium attracts more low-density lipoproteins, also known as LDL or “bad” cholesterol. The build up of LDL in the artery wall can eventually lead to the plaque that causes atherosclerosis. The plaque is extremely dangerous, especially if unstable, because it can grow without symptoms for years and then without warning rupture, forming a …show more content…
“Cardiac cells can withstand ischemic conditions for approximately twenty minutes before irreversible hypoxic injury causes cellular death (apoptosis) and tissue necrosis” (Huether & McCance, 2012, pg. 606). During a MI, five hundred myocytes perish per minute. The majority of those heart cells are unable to regenerate once they have been destroyed. Many cardiologists use the expression “time is muscle” to help convey the importance of immediate treatment (Antman, 2008). If an area of the heart is ischemic due to vascular occlusion, the goal is to reperfuse the heart with oxygenated blood. Perfusion is the passage of fluid through a specific organ or area of the body, for example perfusing blood into the tissues of the
Hypertension is a consistent increase of systemic arterial blood pressure, which is influenced by cardiac output and peripheral vascular resistance. The equation for cardiac output is stroke volume (liters per heart beat) multiplied by heart rate (beats per minute). Peripheral vascular resistance is the opposition to the flow of blood that the heart must overcome, which can increase due to an occlusion or vessel edema. With hypertension, cardiac output and stroke volume decreases as heart rate and peripheral resistance increases due to overcompensation of the heart (Huether & McCance 2012). When the heart beats, it propels blood through the arteries to increase circulation throughout your entire body. Higher blood pressures mean that with each beat, arteries throughout the body swell and stretch more than they would normally. Stretching of the endothelium, the delicate lining of all arteries, can cause injury and result in arteries becoming stiffer over time. Healthy endothelium actively works to prevent atherosclerosis from developing. Injured endothelium attracts more low-density lipoproteins, also known as LDL or “bad” cholesterol. The build up of LDL in the artery wall can eventually lead to the plaque that causes atherosclerosis. The plaque is extremely dangerous, especially if unstable, because it can grow without symptoms for years and then without warning rupture, forming a …show more content…
“Cardiac cells can withstand ischemic conditions for approximately twenty minutes before irreversible hypoxic injury causes cellular death (apoptosis) and tissue necrosis” (Huether & McCance, 2012, pg. 606). During a MI, five hundred myocytes perish per minute. The majority of those heart cells are unable to regenerate once they have been destroyed. Many cardiologists use the expression “time is muscle” to help convey the importance of immediate treatment (Antman, 2008). If an area of the heart is ischemic due to vascular occlusion, the goal is to reperfuse the heart with oxygenated blood. Perfusion is the passage of fluid through a specific organ or area of the body, for example perfusing blood into the tissues of the