{"id":278,"date":"2019-12-08T20:26:33","date_gmt":"2019-12-08T20:26:33","guid":{"rendered":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/chapter\/6-3-common-cardiac-disorders\/"},"modified":"2021-12-07T11:17:22","modified_gmt":"2021-12-07T11:17:22","slug":"6-3-common-cardiac-disorders","status":"publish","type":"chapter","link":"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/chapter\/6-3-common-cardiac-disorders\/","title":{"raw":"6.3  Common Cardiac Disorders","rendered":"6.3  Common Cardiac Disorders"},"content":{"raw":"Now that we have reviewed the basic anatomy and physiology concepts of the cardiovascular and renal system, let's discuss some common cardiac disorders.\n<h3><a id=\"_3ib1xmfxfak3\" href=\"\"><\/a>Hyperlipidemia<\/h3>\nCholesterol is a fat (also called a lipid) that your body needs to work properly. However, too much bad cholesterol can increase the risk for heart disease, stroke, and peripheral vascular disease. The medical term for high blood cholesterol is <strong>[pb_glossary id=\"2715\"]hyperlipidemia[\/pb_glossary]<\/strong>. There are many types of cholesterol (see Figure 6.16 for basic types of cholesterol.<sup>[footnote]\"<a href=\"https:\/\/www.flickr.com\/photos\/thaotyphucom\/7123261417\" target=\"_blank\" rel=\"noopener noreferrer\">m\u00e1u nhi\u1ec5m m\u1ee1 - cholesterol<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/thaotyphucom\/\" target=\"_blank\" rel=\"noopener noreferrer\">L\u00ca V\u0102N TH\u1ea2O<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 2.0<\/a>[\/footnote]<\/sup>)\n<ul>\n \t<li><strong>Total cholesterol<\/strong>: All the cholesterols combined<\/li>\n \t<li><strong>High density lipoprotein (HDL) cholesterol:<\/strong> Often called \"good\" cholesterol because it promotes the excretion of cholesterol. Exercise helps to increase HDL and remove cholesterol from the bloodstream<\/li>\n \t<li><strong>Low density lipoprotein (LDL) cholesterol:<\/strong> Often called \"bad\" cholesterol because it stores cholesterol in the bloodstream, which contributes to atherosclerosis<\/li>\n<\/ul>\n[caption id=\"\" align=\"aligncenter\" width=\"500\"]<img class=\"\" title=\"&quot;m\u00e1u nhi\u1ec5m m\u1ee1 - cholesterol&quot; by L\u00ca V\u0102N TH\u1ea2O is licensed under CC BY-SA 2.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2019\/12\/image16.png\" alt=\"Illustration, with labels, showing bad versus good cholesterol\" width=\"500\" height=\"279\"> Figure 6.16 A comparison of LDL (bad cholesterol) and HDL (good cholesterol)[\/caption]\n\nFor many people, abnormal cholesterol levels are partly due to lifestyle choices, including a diet that is high in fat, being overweight, or lack of exercise. However, disorders can also be passed down through families that lead to abnormal cholesterol and triglyceride levels.<sup>[footnote]A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M., Inc.; c2019. High blood cholesterol levels; [reviewed 2018 February 22; updated 2018 March 28; cited 2019 November 29]. <a href=\"https:\/\/medlineplus.gov\/ency\/article\/000403.htm\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/medlineplus.gov\/ency\/article\/000403.htm<\/a>.[\/footnote]<\/sup> In addition to lifestyle modifications such as a low-fat diet and exercise, hyperlipidemia is treated with antilipidemic medication such as atorvastatin (Lipitor) to help prevent long-term complications.\n<h3>Hypertension<\/h3>\nChronically elevated blood pressure is known clinically as hypertension. High blood pressure is treated with lifestyle changes and medication. New American Heart Association guidelines state that hypertension should be treated at 130\/80 mm Hg rather than the previous standard of 140\/90.<sup>[footnote]Whelton, P.K., Carey R.M., Aronow W.S., et. al. (2018). 2017 Guideline for high blood pressure in adults. <em>Journal of the American College of Cardiology, 71<\/em>. <a href=\"https:\/\/www.acc.org\/latest-in-cardiology\/ten-points-to-remember\/2017\/11\/09\/11\/41\/2017-guideline-for-high-blood-pressure-in-adults\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.acc.org\/latest-in-cardiology\/ten-points-to-remember\/2017\/11\/09\/11\/41\/2017-guideline-for-high-blood-pressure-in-adults<\/a>.[\/footnote]<\/sup> See Figure 6.17<sup>[footnote]\"<a href=\"https:\/\/www.flickr.com\/photos\/b-may\/361018310\" target=\"_blank\" rel=\"noopener noreferrer\">Monthly check up.<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/b-may\/\" target=\"_blank\" rel=\"noopener noreferrer\">Bryan Mason<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 2.0<\/a>[\/footnote]<\/sup> for an image of a health care professional obtaining an accurate blood pressure reading that will be used to determine a treatment plan for the patient.\n\n[caption id=\"\" align=\"aligncenter\" width=\"825\"]<img title=\"&quot;Blood Pressure&quot; by Bryan Mason is licensed under CC BY 4.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image17.png\" alt=\"Photo showing blood pressure being taken\" width=\"825\" height=\"550\"> Figure 6.17 It is critical to obtain an accurate blood pressure that will be used for the development of a treatment plan for hypertension[\/caption]\n\nAbout 68 million Americans currently suffer from hypertension. Unfortunately, hypertension is often a silent disorder, meaning no symptoms occur until complications happen, so patients may fail to recognize the seriousness of their condition and fail to follow their treatment plan. The result is often a heart attack or stroke. Hypertension may also lead to an aneurysm (ballooning of a blood vessel caused by a weakening of the wall), peripheral arterial disease (obstruction of vessels in peripheral regions of the body), myocardial infarction, chronic kidney disease, or heart failure.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n\nMany cardiovascular medications are commonly used to treat hypertension such as diuretics, ACE inhibitors, beta blockers, and calcium channel blockers.\n<h3><a id=\"_p9nvjj9c7pie\" href=\"\"><\/a>Thrombi and Emboli<\/h3>\nThrombi are most commonly caused by vessel damage to the endothelial lining, which activates the clotting mechanism. A thrombus can seriously impede blood flow to tissue or organs. Deep vein thrombosis (DVT) can occur when blood in the veins, particularly in the legs, remains stationary for long periods, such as during and after surgery. See Figure 6.18<sup>[footnote]This work is a derivative of \"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Deep_vein_thrombosis_of_the_right_leg.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">Deep vein thrombosis of the right leg.jpg<\/a>\" by <a href=\"https:\/\/commons.wikimedia.org\/wiki\/User:Jmh649\" target=\"_blank\" rel=\"noopener noreferrer\">James Heilman, MD<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 3.0<\/a>[\/footnote]<\/sup> for an image of a patient experiencing typical symptoms of a DVT, including unilateral edema and redness.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]<img title=\"&quot;Deep vein thrombosis of the right leg.jpg&quot; by James Heilman, MD is licensed under CC BY-SA 3.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image18.png\" alt=\"Photo showing signs of DVT on the right leg\" width=\"800\" height=\"1279\"> Figure 6.18 Typical signs of a DVT include unilateral edema and redness[\/caption]\n\nWhen a portion of a thrombus breaks free from the vessel wall and enters the circulation, it is referred to as an embolus. An <strong>embolus<\/strong> that is carried through the bloodstream can be large enough to block a vessel critical to a major organ. When it becomes trapped, an embolus is called an embolism. In the heart, brain, or lungs, an embolism may cause a heart attack, a cerebrovascular accident (CVA) or otherwise known as a stroke, or a pulmonary embolism. These are medical emergencies.\n\nMedications such as aspirin and warfarin are used to prevent the formation of clots in people who are at risk. Heparin is a medication that can be used to prevent or treat clots, and tPA is used to dissolve severe clots causing ischemia in the brain, heart, or lungs.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n<h3><a id=\"_7ar1gjky0rb\" href=\"\"><\/a>Atherosclerosis<\/h3>\n<strong>[pb_glossary id=\"2807\"]Arteriosclerosis [\/pb_glossary]<\/strong> begins with injury to the endothelium of an artery, which may be caused by irritation from high blood glucose, infection, tobacco use, excessive blood lipids, and other factors. Injured artery walls causes inflammation. As inflammation spreads into the artery wall, it weakens and scars it, leaving it stiff. Circulating triglycerides and cholesterol can seep between the damaged lining cells and become trapped within the artery wall, where they are joined by leukocytes, calcium, and cellular debris. Eventually, this buildup, called plaque, can narrow arteries enough to impair blood flow. The term for this condition, atherosclerosis, describes the plaque deposits. See Figure 6.19<sup>[footnote]\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2113ab_Atherosclerosis.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">2113ab Atherosclerosis.jpg<\/a>\" by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax College<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY 4.0.<\/a> Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance<\/a>[\/footnote]<\/sup> for an illustration of atherosclerosis.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n\n[caption id=\"\" align=\"aligncenter\" width=\"1965\"]<img title=\"&quot;2113ab Atherosclerosis.jpg&quot; by OpenStax College is licensed under CC BY 4.0 Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image19.png\" alt=\"Illustration and micrograph, showing atherosclerosis\" width=\"1965\" height=\"1065\"> Figure 6.19 Atherosclerosis[\/caption]\n\nSometimes a plaque can rupture, causing microscopic tears in the artery wall that allow blood to leak into the tissue on the other side. When this happens, platelets rush to the site to clot the blood. This clot can further obstruct the artery and\u2014if it occurs in a coronary or cerebral artery\u2014cause a sudden heart attack or stroke. Alternatively, plaque can also break off and travel through the bloodstream as an <strong>[pb_glossary id=\"2722\"]embolus [\/pb_glossary]<\/strong> until it blocks a more distant, smaller artery.\n\nEven without total blockage, narrowed vessels lead to <strong>[pb_glossary id=\"2724\"]ischemia[\/pb_glossary]<\/strong> (reduced blood flow to the tissue region \"downstream\" of the narrowed vessel). Ischemia can lead to hypoxia (decreased supply of oxygen to the tissues), causing a myocardial infarction or cerebrovascular accident.\n\nTreatment of atherosclerosis includes lifestyle changes, such as weight loss, smoking cessation, regular exercise, and adoption of a diet low in sodium and saturated fats. Antilipemic medications such as atorvastatin are prescribed to reduce cholesterol and help prevent atherosclerosis.\n<h3><a id=\"_dagzfe4jbrp3\" href=\"\"><\/a>Coronary Artery Disease<\/h3>\nCoronary artery disease is the leading cause of death worldwide. It occurs when atherosclerosis within the walls of the coronary arteries obstructs blood flow. As the coronary blood vessels become blocked with plaque, the flow of blood to the tissues is restricted, causing the cardiac cells to receive insufficient amounts of oxygen, which can cause pain called angina. Figure 6.20<sup>[footnote]\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2016_Occluded_Coronay_Arteries.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">2016 Occluded Coronay Arteries.jpg<\/a>\" by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax College<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 3.0<\/a>[\/footnote]<\/sup> shows the blockage of coronary arteries highlighted by the injection of dye. Some individuals with coronary artery disease report pain radiating from the chest called angina, but others, especially women, may remain asymptomatic or have alternative symptoms of neck, jaw, shoulder, upper back, or abdominal pain. If untreated, coronary artery disease can lead to a <strong>[pb_glossary id=\"2727\"]myocardial infarction[\/pb_glossary]<\/strong> (heart attack). Risk factors include smoking, family history, hypertension, obesity, diabetes, lack of exercise, stress, and hyperlipidemia. Treatments may include medication, changes to diet and exercise, a coronary angioplasty with a balloon catheter, insertion of a stent, or coronary bypass procedure.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n\n[caption id=\"\" align=\"aligncenter\" width=\"561\"]<img title=\"&quot;2016 Occluded Coronay Arteries.jpg&quot; by OpenStax College is licensed under CC BY 3.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image20.png\" alt=\"Photo of Chordae Tendineae and Papillary Muscles\" width=\"561\" height=\"561\"> Figure 6.20 Image of blocked coronary arteries highlighted by the injection of dye during a coronary angiogram[\/caption]\n<h3><a id=\"_lewd06kk7i9i\" href=\"\"><\/a>Myocardial Infarction<\/h3>\nMyocardial infarction (MI) is the medical term for what is commonly referred to as a \"heart attack.\" It results from a lack of blood flow and oxygen to a region of the heart, resulting in death of the cardiac muscle cells. An MI often occurs when a coronary artery is blocked by the buildup of atherosclerotic plaque and becomes a thrombus or when a portion of an unstable atherosclerotic plaque travels through the coronary arterial system and lodges in one of the smaller vessels.\n\nIn the case of acute MI, there is often sudden pain beneath the sternum (retrosternal pain) called angina, often radiating down the left arm in male patients, but not as commonly in female patients (see Figure 6.21).<sup>[footnote]\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:A_man_having_a_Heart_Attack.png\" target=\"_blank\" rel=\"noopener noreferrer\">A man having a Heart Attack.png<\/a>\" by <a href=\"https:\/\/www.myupchar.com\/en\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.myupchar.com\/en<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/deed.en\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 4.0<\/a>[\/footnote]<\/sup>\u00a0In addition, patients typically present with difficulty breathing and shortness of breath (dyspnea), irregular heartbeat (palpitations), nausea and vomiting, sweating (diaphoresis), anxiety, and fainting (syncope), although not all of these symptoms may be present. Many of the symptoms are shared with other medical conditions, including anxiety attacks and simple indigestion, so accurate diagnosis is critical for survival.\n\nAn MI can be confirmed by examining the patient's ECG, which frequently reveals alterations in the ST and Q components. Immediate treatments for MI are required and include administering supplemental oxygen, aspirin, and nitroglycerin. Longer-term treatments may include injections of thrombolytic agents such as tPA that dissolve the clot, along with the anticoagulant heparin, a balloon angioplasty with stents to open blocked vessels, or bypass surgery to allow blood to pass around the site of blockage.<sup>[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote]<\/sup>\n<div class=\"mceTemp\"><\/div>\n\n[caption id=\"attachment_277\" align=\"aligncenter\" width=\"1024\"]<img class=\"wp-image-275 size-large\" title=\"&quot;A man having a Heart Attack.png&quot; by https:\/\/www.myupchar.com\/en is licensed under CC BY-SA 4.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-1024x655.png\" alt=\"illustration of Man having a heart attack\" width=\"1024\" height=\"655\"> Figure 6.21 Male patients often describe chest pain associated with MI \"like something is sitting on my chest,\" but female patients may simply have feelings of GI upset[\/caption]\n\n&nbsp;\n<h3><a id=\"_24tj1myauxz\" href=\"\"><\/a>Cerebrovascular Accident (CVA)<\/h3>\nThe internal carotid arteries, along with the vertebral arteries, are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. However, blood flow may become obstructed due to atherosclerosis or an emboli that has traveled from elsewhere in the blood. For example, an arrhythmia called atrial fibrillation can cause clots to form in the heart that then move to the brain. When blood flow is interrupted, even for just a few seconds, a <strong>[pb_glossary id=\"2730\"]transient ischemic attack (TIA)[\/pb_glossary]<\/strong><span style=\"text-align: initial;font-size: 1em\">, or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. Loss of blood flow for longer periods produce irreversible brain damage or a stroke, also called a <strong>[pb_glossary id=\"2732\"]<\/strong><\/span><strong>cerebrovascular accident (CVA)[\/pb_glossary]<\/strong><span style=\"text-align: initial;font-size: 1em\">.<\/span><sup style=\"text-align: initial\">[footnote]This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a>[\/footnote] <\/sup><span style=\"text-align: initial;font-size: 1em\">There are two types of cerebrovascular accidents: ischemia and hemorrhagic. Ischemic strokes are caused by atherosclerosis or a blood clot that blocks the flow of blood to the brain (see Figure 6.22).<sup>[footnote]\"<a href=\"https:\/\/www.flickr.com\/photos\/constructiondeal_marketing\/4254385133\" target=\"_blank\" rel=\"noopener noreferrer\">Stroke Diagram<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/constructiondeal_marketing\/4254385133\" target=\"_blank\" rel=\"noopener noreferrer\">ConstructionDealMkting<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 2.0<\/a>[\/footnote]<\/sup>\u00a0Eighty percent of strokes are ischemic. Hemorrhagic strokes are caused by a blood vessel that ruptures and bleeds into the brain. Risk factors for a stroke include smoking, high blood pressure, and cardiac arrhythmias. Treatment of a stroke depends on the cause.<\/span><sup style=\"text-align: initial\">[footnote]Anderson, P. &amp; Townsend, T. (2015) Preventing high-alert medication errors in hospital patients. <em>Nurse Today, 10<\/em>(5). <a href=\"https:\/\/www.americannursetoday.com\/wp-content\/uploads\/2015\/05\/ant5-CE-421.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.americannursetoday.com\/wp-content\/uploads\/2015\/05\/ant5-CE-421.pdf<\/a>[\/footnote]<\/sup><span style=\"text-align: initial;font-size: 1em\">\u00a0Ischemic strokes are treated with thrombolytic medication such as tPA to dissolve the clot, whereas hemorrhagic strokes often require surgery to stop the bleeding.<\/span>\n\n[caption id=\"\" align=\"aligncenter\" width=\"402\"]<img class=\"\" title=\"&quot;Stroke Diagram&quot; by ConstructionDealMkting is licensed under CC BY 2.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image22.png\" alt=\"Illustration, with labels, showing stroke\" width=\"402\" height=\"270\"> Figure 6.22 Ischemic Stroke[\/caption]\n<h3><a id=\"_owqtgo3g17v9\" href=\"\"><\/a>Arrhythmias<\/h3>\nOccasionally, an area of the heart other than the SA node will initiate an impulse that will be followed by a premature contraction. Such an area is known as an ectopic focus. An ectopic focus may be stimulated by localized ischemia, exposure to certain drugs, elevated stimulation by both sympathetic or parasympathetic divisions of the autonomic nervous system, or several diseases or pathological conditions. Occasional occurrences are generally transitory and nonlife threatening, but if the condition becomes chronic, it may lead to either an <strong>[pb_glossary id=\"2734\"]arrhythmia,[\/pb_glossary]<\/strong>\u00a0a deviation from the normal pattern of impulse conduction and contraction, or to <strong>[pb_glossary id=\"2735\"]fibrillation,[\/pb_glossary]<\/strong> an uncoordinated beating of the heart. Severe arrhythmias can lead to cardiac arrest, which is fatal if not treated within a few minutes. Abnormalities that may be detected by the ECGs are shown in Figure 6.23.<sup>[footnote]\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2024_Cardiac_Arrhythmias.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">Common ECG Abnormalities<\/a>\" by <a href=\"https:\/\/cnx.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">CNX OpenStax<\/a> is licensed under<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\"> CC BY 4.0.<\/a> Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity<\/a>[\/footnote]<\/sup> Antiarrhythmic medications such as sotalol, diltiazem, and amiodarone are used to treat arrhythmias.\n\n[caption id=\"\" align=\"aligncenter\" width=\"2000\"]<img title=\"&quot;Common ECG Abnormalities&quot; by CNX OpenStax is licensed under CC BY 4.0 Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image23.png\" alt=\"Illustrations showing comparisons of common ECG abnormalities\" width=\"2000\" height=\"2050\"> Figure 6.23 Sample arrhythmias: a) In a second-degree or partial block, one-half of the P waves are not followed by the QRS complex and T waves while the other half are. (b) In atrial fibrillation, the electrical pattern is abnormal prior to the QRS complex, and the frequency between the QRS complexes has increased. (c) In ventricular tachycardia, the shape of the QRS complex is abnormal. (d) In ventricular fibrillation, there is no normal electrical activity. (e) In a third-degree block, there is no correlation between atrial activity (the P wave) and ventricular activity (the QRS complex)[\/caption]\n<h3><a id=\"_km7h5ru4sml3\" href=\"\"><\/a>Heart Failure<\/h3>\nHeart failure is a condition in which the heart can't pump enough blood to meet the body's needs. Right-side heart failure occurs if the heart can't pump enough blood to the lungs to pick up oxygen, whereas left-side heart failure occurs if the heart can't pump enough oxygen-rich blood to the rest of the body. Heart failure is a very common condition with over 5.7 million people in the United States having this chronic condition. There is no cure, but the symptoms can be managed for several years with lifestyle modifications and several different types of medications. Causes of heart failure include hypertension, myocardial infarction, and other cardiac and respiratory diseases. Common symptoms of heart failure include peripheral edema and shortness of breath that occur as a result of fluid overload. Many patients are treated with diuretics to manage the symptoms of fluid overload and with antihypertensives to manage the blood pressure. Other medications such as digoxin and dobutamine may also be used to increase the contractility of the heart.<sup>[footnote]National Heart, Lung, and Blood, National Institute of Health (2019). <em>Heart failure.<\/em> <a href=\"https:\/\/www.nhlbi.nih.gov\/health-topics\/heart-failure\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.nhlbi.nih.gov\/health-topics\/heart-failure<\/a>[\/footnote]<\/sup>","rendered":"<p>Now that we have reviewed the basic anatomy and physiology concepts of the cardiovascular and renal system, let&#8217;s discuss some common cardiac disorders.<\/p>\n<h3><a id=\"_3ib1xmfxfak3\" href=\"\"><\/a>Hyperlipidemia<\/h3>\n<p>Cholesterol is a fat (also called a lipid) that your body needs to work properly. However, too much bad cholesterol can increase the risk for heart disease, stroke, and peripheral vascular disease. The medical term for high blood cholesterol is <strong>hyperlipidemia<\/strong>. There are many types of cholesterol (see Figure 6.16 for basic types of cholesterol.<sup><a class=\"footnote\" title=\"&quot;m\u00e1u nhi\u1ec5m m\u1ee1 - cholesterol&quot; by L\u00ca V\u0102N TH\u1ea2O is licensed under CC BY-SA 2.0\" id=\"return-footnote-278-1\" href=\"#footnote-278-1\" aria-label=\"Footnote 1\"><sup class=\"footnote\">[1]<\/sup><\/a><\/sup>)<\/p>\n<ul>\n<li><strong>Total cholesterol<\/strong>: All the cholesterols combined<\/li>\n<li><strong>High density lipoprotein (HDL) cholesterol:<\/strong> Often called &#8220;good&#8221; cholesterol because it promotes the excretion of cholesterol. Exercise helps to increase HDL and remove cholesterol from the bloodstream<\/li>\n<li><strong>Low density lipoprotein (LDL) cholesterol:<\/strong> Often called &#8220;bad&#8221; cholesterol because it stores cholesterol in the bloodstream, which contributes to atherosclerosis<\/li>\n<\/ul>\n<figure style=\"width: 500px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"\" title=\"&quot;m\u00e1u nhi\u1ec5m m\u1ee1 - cholesterol&quot; by L\u00ca V\u0102N TH\u1ea2O is licensed under CC BY-SA 2.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2019\/12\/image16.png\" alt=\"Illustration, with labels, showing bad versus good cholesterol\" width=\"500\" height=\"279\" \/><figcaption class=\"wp-caption-text\">Figure 6.16 A comparison of LDL (bad cholesterol) and HDL (good cholesterol)<\/figcaption><\/figure>\n<p>For many people, abnormal cholesterol levels are partly due to lifestyle choices, including a diet that is high in fat, being overweight, or lack of exercise. However, disorders can also be passed down through families that lead to abnormal cholesterol and triglyceride levels.<sup><a class=\"footnote\" title=\"A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M., Inc.; c2019. High blood cholesterol levels; [reviewed 2018 February 22; updated 2018 March 28; cited 2019 November 29]. https:\/\/medlineplus.gov\/ency\/article\/000403.htm.\" id=\"return-footnote-278-2\" href=\"#footnote-278-2\" aria-label=\"Footnote 2\"><sup class=\"footnote\">[2]<\/sup><\/a><\/sup> In addition to lifestyle modifications such as a low-fat diet and exercise, hyperlipidemia is treated with antilipidemic medication such as atorvastatin (Lipitor) to help prevent long-term complications.<\/p>\n<h3>Hypertension<\/h3>\n<p>Chronically elevated blood pressure is known clinically as hypertension. High blood pressure is treated with lifestyle changes and medication. New American Heart Association guidelines state that hypertension should be treated at 130\/80 mm Hg rather than the previous standard of 140\/90.<sup><a class=\"footnote\" title=\"Whelton, P.K., Carey R.M., Aronow W.S., et. al. (2018). 2017 Guideline for high blood pressure in adults. Journal of the American College of Cardiology, 71. https:\/\/www.acc.org\/latest-in-cardiology\/ten-points-to-remember\/2017\/11\/09\/11\/41\/2017-guideline-for-high-blood-pressure-in-adults.\" id=\"return-footnote-278-3\" href=\"#footnote-278-3\" aria-label=\"Footnote 3\"><sup class=\"footnote\">[3]<\/sup><\/a><\/sup> See Figure 6.17<sup><a class=\"footnote\" title=\"&quot;Monthly check up.&quot; by Bryan Mason is licensed under CC BY 2.0\" id=\"return-footnote-278-4\" href=\"#footnote-278-4\" aria-label=\"Footnote 4\"><sup class=\"footnote\">[4]<\/sup><\/a><\/sup> for an image of a health care professional obtaining an accurate blood pressure reading that will be used to determine a treatment plan for the patient.<\/p>\n<figure style=\"width: 825px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" title=\"&quot;Blood Pressure&quot; by Bryan Mason is licensed under CC BY 4.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image17.png\" alt=\"Photo showing blood pressure being taken\" width=\"825\" height=\"550\" \/><figcaption class=\"wp-caption-text\">Figure 6.17 It is critical to obtain an accurate blood pressure that will be used for the development of a treatment plan for hypertension<\/figcaption><\/figure>\n<p>About 68 million Americans currently suffer from hypertension. Unfortunately, hypertension is often a silent disorder, meaning no symptoms occur until complications happen, so patients may fail to recognize the seriousness of their condition and fail to follow their treatment plan. The result is often a heart attack or stroke. Hypertension may also lead to an aneurysm (ballooning of a blood vessel caused by a weakening of the wall), peripheral arterial disease (obstruction of vessels in peripheral regions of the body), myocardial infarction, chronic kidney disease, or heart failure.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-5\" href=\"#footnote-278-5\" aria-label=\"Footnote 5\"><sup class=\"footnote\">[5]<\/sup><\/a><\/sup><\/p>\n<p>Many cardiovascular medications are commonly used to treat hypertension such as diuretics, ACE inhibitors, beta blockers, and calcium channel blockers.<\/p>\n<h3><a id=\"_p9nvjj9c7pie\" href=\"\"><\/a>Thrombi and Emboli<\/h3>\n<p>Thrombi are most commonly caused by vessel damage to the endothelial lining, which activates the clotting mechanism. A thrombus can seriously impede blood flow to tissue or organs. Deep vein thrombosis (DVT) can occur when blood in the veins, particularly in the legs, remains stationary for long periods, such as during and after surgery. See Figure 6.18<sup><a class=\"footnote\" title=\"This work is a derivative of &quot;Deep vein thrombosis of the right leg.jpg&quot; by James Heilman, MD is licensed under CC BY-SA 3.0\" id=\"return-footnote-278-6\" href=\"#footnote-278-6\" aria-label=\"Footnote 6\"><sup class=\"footnote\">[6]<\/sup><\/a><\/sup> for an image of a patient experiencing typical symptoms of a DVT, including unilateral edema and redness.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-7\" href=\"#footnote-278-7\" aria-label=\"Footnote 7\"><sup class=\"footnote\">[7]<\/sup><\/a><\/sup><\/p>\n<figure style=\"width: 800px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" title=\"&quot;Deep vein thrombosis of the right leg.jpg&quot; by James Heilman, MD is licensed under CC BY-SA 3.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image18.png\" alt=\"Photo showing signs of DVT on the right leg\" width=\"800\" height=\"1279\" \/><figcaption class=\"wp-caption-text\">Figure 6.18 Typical signs of a DVT include unilateral edema and redness<\/figcaption><\/figure>\n<p>When a portion of a thrombus breaks free from the vessel wall and enters the circulation, it is referred to as an embolus. An <strong>embolus<\/strong> that is carried through the bloodstream can be large enough to block a vessel critical to a major organ. When it becomes trapped, an embolus is called an embolism. In the heart, brain, or lungs, an embolism may cause a heart attack, a cerebrovascular accident (CVA) or otherwise known as a stroke, or a pulmonary embolism. These are medical emergencies.<\/p>\n<p>Medications such as aspirin and warfarin are used to prevent the formation of clots in people who are at risk. Heparin is a medication that can be used to prevent or treat clots, and tPA is used to dissolve severe clots causing ischemia in the brain, heart, or lungs.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-8\" href=\"#footnote-278-8\" aria-label=\"Footnote 8\"><sup class=\"footnote\">[8]<\/sup><\/a><\/sup><\/p>\n<h3><a id=\"_7ar1gjky0rb\" href=\"\"><\/a>Atherosclerosis<\/h3>\n<p><strong>Arteriosclerosis <\/strong> begins with injury to the endothelium of an artery, which may be caused by irritation from high blood glucose, infection, tobacco use, excessive blood lipids, and other factors. Injured artery walls causes inflammation. As inflammation spreads into the artery wall, it weakens and scars it, leaving it stiff. Circulating triglycerides and cholesterol can seep between the damaged lining cells and become trapped within the artery wall, where they are joined by leukocytes, calcium, and cellular debris. Eventually, this buildup, called plaque, can narrow arteries enough to impair blood flow. The term for this condition, atherosclerosis, describes the plaque deposits. See Figure 6.19<sup><a class=\"footnote\" title=\"&quot;2113ab Atherosclerosis.jpg&quot; by OpenStax College is licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance\" id=\"return-footnote-278-9\" href=\"#footnote-278-9\" aria-label=\"Footnote 9\"><sup class=\"footnote\">[9]<\/sup><\/a><\/sup> for an illustration of atherosclerosis.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-10\" href=\"#footnote-278-10\" aria-label=\"Footnote 10\"><sup class=\"footnote\">[10]<\/sup><\/a><\/sup><\/p>\n<figure style=\"width: 1965px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" title=\"&quot;2113ab Atherosclerosis.jpg&quot; by OpenStax College is licensed under CC BY 4.0 Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image19.png\" alt=\"Illustration and micrograph, showing atherosclerosis\" width=\"1965\" height=\"1065\" \/><figcaption class=\"wp-caption-text\">Figure 6.19 Atherosclerosis<\/figcaption><\/figure>\n<p>Sometimes a plaque can rupture, causing microscopic tears in the artery wall that allow blood to leak into the tissue on the other side. When this happens, platelets rush to the site to clot the blood. This clot can further obstruct the artery and\u2014if it occurs in a coronary or cerebral artery\u2014cause a sudden heart attack or stroke. Alternatively, plaque can also break off and travel through the bloodstream as an <strong>embolus <\/strong> until it blocks a more distant, smaller artery.<\/p>\n<p>Even without total blockage, narrowed vessels lead to <strong>ischemia<\/strong> (reduced blood flow to the tissue region &#8220;downstream&#8221; of the narrowed vessel). Ischemia can lead to hypoxia (decreased supply of oxygen to the tissues), causing a myocardial infarction or cerebrovascular accident.<\/p>\n<p>Treatment of atherosclerosis includes lifestyle changes, such as weight loss, smoking cessation, regular exercise, and adoption of a diet low in sodium and saturated fats. Antilipemic medications such as atorvastatin are prescribed to reduce cholesterol and help prevent atherosclerosis.<\/p>\n<h3><a id=\"_dagzfe4jbrp3\" href=\"\"><\/a>Coronary Artery Disease<\/h3>\n<p>Coronary artery disease is the leading cause of death worldwide. It occurs when atherosclerosis within the walls of the coronary arteries obstructs blood flow. As the coronary blood vessels become blocked with plaque, the flow of blood to the tissues is restricted, causing the cardiac cells to receive insufficient amounts of oxygen, which can cause pain called angina. Figure 6.20<sup><a class=\"footnote\" title=\"&quot;2016 Occluded Coronay Arteries.jpg&quot; by OpenStax College is licensed under CC BY 3.0\" id=\"return-footnote-278-11\" href=\"#footnote-278-11\" aria-label=\"Footnote 11\"><sup class=\"footnote\">[11]<\/sup><\/a><\/sup> shows the blockage of coronary arteries highlighted by the injection of dye. Some individuals with coronary artery disease report pain radiating from the chest called angina, but others, especially women, may remain asymptomatic or have alternative symptoms of neck, jaw, shoulder, upper back, or abdominal pain. If untreated, coronary artery disease can lead to a <strong>myocardial infarction<\/strong> (heart attack). Risk factors include smoking, family history, hypertension, obesity, diabetes, lack of exercise, stress, and hyperlipidemia. Treatments may include medication, changes to diet and exercise, a coronary angioplasty with a balloon catheter, insertion of a stent, or coronary bypass procedure.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-12\" href=\"#footnote-278-12\" aria-label=\"Footnote 12\"><sup class=\"footnote\">[12]<\/sup><\/a><\/sup><\/p>\n<figure style=\"width: 561px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" title=\"&quot;2016 Occluded Coronay Arteries.jpg&quot; by OpenStax College is licensed under CC BY 3.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image20.png\" alt=\"Photo of Chordae Tendineae and Papillary Muscles\" width=\"561\" height=\"561\" \/><figcaption class=\"wp-caption-text\">Figure 6.20 Image of blocked coronary arteries highlighted by the injection of dye during a coronary angiogram<\/figcaption><\/figure>\n<h3><a id=\"_lewd06kk7i9i\" href=\"\"><\/a>Myocardial Infarction<\/h3>\n<p>Myocardial infarction (MI) is the medical term for what is commonly referred to as a &#8220;heart attack.&#8221; It results from a lack of blood flow and oxygen to a region of the heart, resulting in death of the cardiac muscle cells. An MI often occurs when a coronary artery is blocked by the buildup of atherosclerotic plaque and becomes a thrombus or when a portion of an unstable atherosclerotic plaque travels through the coronary arterial system and lodges in one of the smaller vessels.<\/p>\n<p>In the case of acute MI, there is often sudden pain beneath the sternum (retrosternal pain) called angina, often radiating down the left arm in male patients, but not as commonly in female patients (see Figure 6.21).<sup><a class=\"footnote\" title=\"&quot;A man having a Heart Attack.png&quot; by https:\/\/www.myupchar.com\/en is licensed under CC BY-SA 4.0\" id=\"return-footnote-278-13\" href=\"#footnote-278-13\" aria-label=\"Footnote 13\"><sup class=\"footnote\">[13]<\/sup><\/a><\/sup>\u00a0In addition, patients typically present with difficulty breathing and shortness of breath (dyspnea), irregular heartbeat (palpitations), nausea and vomiting, sweating (diaphoresis), anxiety, and fainting (syncope), although not all of these symptoms may be present. Many of the symptoms are shared with other medical conditions, including anxiety attacks and simple indigestion, so accurate diagnosis is critical for survival.<\/p>\n<p>An MI can be confirmed by examining the patient&#8217;s ECG, which frequently reveals alterations in the ST and Q components. Immediate treatments for MI are required and include administering supplemental oxygen, aspirin, and nitroglycerin. Longer-term treatments may include injections of thrombolytic agents such as tPA that dissolve the clot, along with the anticoagulant heparin, a balloon angioplasty with stents to open blocked vessels, or bypass surgery to allow blood to pass around the site of blockage.<sup><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-14\" href=\"#footnote-278-14\" aria-label=\"Footnote 14\"><sup class=\"footnote\">[14]<\/sup><\/a><\/sup><\/p>\n<div class=\"mceTemp\"><\/div>\n<figure id=\"attachment_277\" aria-describedby=\"caption-attachment-277\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-275 size-large\" title=\"&quot;A man having a Heart Attack.png&quot; by https:\/\/www.myupchar.com\/en is licensed under CC BY-SA 4.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-1024x655.png\" alt=\"illustration of Man having a heart attack\" width=\"1024\" height=\"655\" srcset=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-1024x655.png 1024w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-300x192.png 300w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-768x491.png 768w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-1536x983.png 1536w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-2048x1311.png 2048w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-65x42.png 65w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-225x144.png 225w, https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/A_man_having_a_Heart_Attack-350x224.png 350w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption id=\"caption-attachment-277\" class=\"wp-caption-text\">Figure 6.21 Male patients often describe chest pain associated with MI &#8220;like something is sitting on my chest,&#8221; but female patients may simply have feelings of GI upset<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3><a id=\"_24tj1myauxz\" href=\"\"><\/a>Cerebrovascular Accident (CVA)<\/h3>\n<p>The internal carotid arteries, along with the vertebral arteries, are the two primary suppliers of blood to the human brain. Given the central role and vital importance of the brain to life, it is critical that blood supply to this organ remains uninterrupted. However, blood flow may become obstructed due to atherosclerosis or an emboli that has traveled from elsewhere in the blood. For example, an arrhythmia called atrial fibrillation can cause clots to form in the heart that then move to the brain. When blood flow is interrupted, even for just a few seconds, a <strong>transient ischemic attack (TIA)<\/strong><span style=\"text-align: initial;font-size: 1em\">, or mini-stroke, may occur, resulting in loss of consciousness or temporary loss of neurological function. Loss of blood flow for longer periods produce irreversible brain damage or a stroke, also called a <strong><\/strong><\/span><strong>cerebrovascular accident (CVA)<\/strong><span style=\"text-align: initial;font-size: 1em\">.<\/span><sup style=\"text-align: initial\"><a class=\"footnote\" title=\"This work is a derivative of Anatomy and Physiology by OpenStax licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" id=\"return-footnote-278-15\" href=\"#footnote-278-15\" aria-label=\"Footnote 15\"><sup class=\"footnote\">[15]<\/sup><\/a> <\/sup><span style=\"text-align: initial;font-size: 1em\">There are two types of cerebrovascular accidents: ischemia and hemorrhagic. Ischemic strokes are caused by atherosclerosis or a blood clot that blocks the flow of blood to the brain (see Figure 6.22).<sup><a class=\"footnote\" title=\"&quot;Stroke Diagram&quot; by ConstructionDealMkting is licensed under CC BY 2.0\" id=\"return-footnote-278-16\" href=\"#footnote-278-16\" aria-label=\"Footnote 16\"><sup class=\"footnote\">[16]<\/sup><\/a><\/sup>\u00a0Eighty percent of strokes are ischemic. Hemorrhagic strokes are caused by a blood vessel that ruptures and bleeds into the brain. Risk factors for a stroke include smoking, high blood pressure, and cardiac arrhythmias. Treatment of a stroke depends on the cause.<\/span><sup style=\"text-align: initial\"><a class=\"footnote\" title=\"Anderson, P. &amp; Townsend, T. (2015) Preventing high-alert medication errors in hospital patients. Nurse Today, 10(5). https:\/\/www.americannursetoday.com\/wp-content\/uploads\/2015\/05\/ant5-CE-421.pdf\" id=\"return-footnote-278-17\" href=\"#footnote-278-17\" aria-label=\"Footnote 17\"><sup class=\"footnote\">[17]<\/sup><\/a><\/sup><span style=\"text-align: initial;font-size: 1em\">\u00a0Ischemic strokes are treated with thrombolytic medication such as tPA to dissolve the clot, whereas hemorrhagic strokes often require surgery to stop the bleeding.<\/span><\/p>\n<figure style=\"width: 402px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"\" title=\"&quot;Stroke Diagram&quot; by ConstructionDealMkting is licensed under CC BY 2.0\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image22.png\" alt=\"Illustration, with labels, showing stroke\" width=\"402\" height=\"270\" \/><figcaption class=\"wp-caption-text\">Figure 6.22 Ischemic Stroke<\/figcaption><\/figure>\n<h3><a id=\"_owqtgo3g17v9\" href=\"\"><\/a>Arrhythmias<\/h3>\n<p>Occasionally, an area of the heart other than the SA node will initiate an impulse that will be followed by a premature contraction. Such an area is known as an ectopic focus. An ectopic focus may be stimulated by localized ischemia, exposure to certain drugs, elevated stimulation by both sympathetic or parasympathetic divisions of the autonomic nervous system, or several diseases or pathological conditions. Occasional occurrences are generally transitory and nonlife threatening, but if the condition becomes chronic, it may lead to either an <strong>arrhythmia,<\/strong>\u00a0a deviation from the normal pattern of impulse conduction and contraction, or to <strong>fibrillation,<\/strong> an uncoordinated beating of the heart. Severe arrhythmias can lead to cardiac arrest, which is fatal if not treated within a few minutes. Abnormalities that may be detected by the ECGs are shown in Figure 6.23.<sup><a class=\"footnote\" title=\"&quot;Common ECG Abnormalities&quot; by CNX OpenStax is licensed under CC BY 4.0. Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" id=\"return-footnote-278-18\" href=\"#footnote-278-18\" aria-label=\"Footnote 18\"><sup class=\"footnote\">[18]<\/sup><\/a><\/sup> Antiarrhythmic medications such as sotalol, diltiazem, and amiodarone are used to treat arrhythmias.<\/p>\n<figure style=\"width: 2000px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" title=\"&quot;Common ECG Abnormalities&quot; by CNX OpenStax is licensed under CC BY 4.0 Access for free at https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" src=\"https:\/\/pressbooks.publishdot.com\/nursingpharmacology\/wp-content\/uploads\/sites\/5\/2021\/12\/image23.png\" alt=\"Illustrations showing comparisons of common ECG abnormalities\" width=\"2000\" height=\"2050\" \/><figcaption class=\"wp-caption-text\">Figure 6.23 Sample arrhythmias: a) In a second-degree or partial block, one-half of the P waves are not followed by the QRS complex and T waves while the other half are. (b) In atrial fibrillation, the electrical pattern is abnormal prior to the QRS complex, and the frequency between the QRS complexes has increased. (c) In ventricular tachycardia, the shape of the QRS complex is abnormal. (d) In ventricular fibrillation, there is no normal electrical activity. (e) In a third-degree block, there is no correlation between atrial activity (the P wave) and ventricular activity (the QRS complex)<\/figcaption><\/figure>\n<h3><a id=\"_km7h5ru4sml3\" href=\"\"><\/a>Heart Failure<\/h3>\n<p>Heart failure is a condition in which the heart can&#8217;t pump enough blood to meet the body&#8217;s needs. Right-side heart failure occurs if the heart can&#8217;t pump enough blood to the lungs to pick up oxygen, whereas left-side heart failure occurs if the heart can&#8217;t pump enough oxygen-rich blood to the rest of the body. Heart failure is a very common condition with over 5.7 million people in the United States having this chronic condition. There is no cure, but the symptoms can be managed for several years with lifestyle modifications and several different types of medications. Causes of heart failure include hypertension, myocardial infarction, and other cardiac and respiratory diseases. Common symptoms of heart failure include peripheral edema and shortness of breath that occur as a result of fluid overload. Many patients are treated with diuretics to manage the symptoms of fluid overload and with antihypertensives to manage the blood pressure. Other medications such as digoxin and dobutamine may also be used to increase the contractility of the heart.<sup><a class=\"footnote\" title=\"National Heart, Lung, and Blood, National Institute of Health (2019). Heart failure. https:\/\/www.nhlbi.nih.gov\/health-topics\/heart-failure\" id=\"return-footnote-278-19\" href=\"#footnote-278-19\" aria-label=\"Footnote 19\"><sup class=\"footnote\">[19]<\/sup><\/a><\/sup><\/p>\n<hr class=\"before-footnotes clear\" \/><div class=\"footnotes\"><ol><li id=\"footnote-278-1\">\"<a href=\"https:\/\/www.flickr.com\/photos\/thaotyphucom\/7123261417\" target=\"_blank\" rel=\"noopener noreferrer\">m\u00e1u nhi\u1ec5m m\u1ee1 - cholesterol<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/thaotyphucom\/\" target=\"_blank\" rel=\"noopener noreferrer\">L\u00ca V\u0102N TH\u1ea2O<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 2.0<\/a> <a href=\"#return-footnote-278-1\" class=\"return-footnote\" aria-label=\"Return to footnote 1\">&crarr;<\/a><\/li><li id=\"footnote-278-2\">A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M., Inc.; c2019. High blood cholesterol levels; [reviewed 2018 February 22; updated 2018 March 28; cited 2019 November 29]. <a href=\"https:\/\/medlineplus.gov\/ency\/article\/000403.htm\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/medlineplus.gov\/ency\/article\/000403.htm<\/a>. <a href=\"#return-footnote-278-2\" class=\"return-footnote\" aria-label=\"Return to footnote 2\">&crarr;<\/a><\/li><li id=\"footnote-278-3\">Whelton, P.K., Carey R.M., Aronow W.S., et. al. (2018). 2017 Guideline for high blood pressure in adults. <em>Journal of the American College of Cardiology, 71<\/em>. <a href=\"https:\/\/www.acc.org\/latest-in-cardiology\/ten-points-to-remember\/2017\/11\/09\/11\/41\/2017-guideline-for-high-blood-pressure-in-adults\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.acc.org\/latest-in-cardiology\/ten-points-to-remember\/2017\/11\/09\/11\/41\/2017-guideline-for-high-blood-pressure-in-adults<\/a>. <a href=\"#return-footnote-278-3\" class=\"return-footnote\" aria-label=\"Return to footnote 3\">&crarr;<\/a><\/li><li id=\"footnote-278-4\">\"<a href=\"https:\/\/www.flickr.com\/photos\/b-may\/361018310\" target=\"_blank\" rel=\"noopener noreferrer\">Monthly check up.<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/b-may\/\" target=\"_blank\" rel=\"noopener noreferrer\">Bryan Mason<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 2.0<\/a> <a href=\"#return-footnote-278-4\" class=\"return-footnote\" aria-label=\"Return to footnote 4\">&crarr;<\/a><\/li><li id=\"footnote-278-5\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-5\" class=\"return-footnote\" aria-label=\"Return to footnote 5\">&crarr;<\/a><\/li><li id=\"footnote-278-6\">This work is a derivative of \"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Deep_vein_thrombosis_of_the_right_leg.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">Deep vein thrombosis of the right leg.jpg<\/a>\" by <a href=\"https:\/\/commons.wikimedia.org\/wiki\/User:Jmh649\" target=\"_blank\" rel=\"noopener noreferrer\">James Heilman, MD<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 3.0<\/a> <a href=\"#return-footnote-278-6\" class=\"return-footnote\" aria-label=\"Return to footnote 6\">&crarr;<\/a><\/li><li id=\"footnote-278-7\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-7\" class=\"return-footnote\" aria-label=\"Return to footnote 7\">&crarr;<\/a><\/li><li id=\"footnote-278-8\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-8\" class=\"return-footnote\" aria-label=\"Return to footnote 8\">&crarr;<\/a><\/li><li id=\"footnote-278-9\">\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2113ab_Atherosclerosis.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">2113ab Atherosclerosis.jpg<\/a>\" by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax College<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY 4.0.<\/a> Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/20-2-blood-flow-blood-pressure-and-resistance<\/a> <a href=\"#return-footnote-278-9\" class=\"return-footnote\" aria-label=\"Return to footnote 9\">&crarr;<\/a><\/li><li id=\"footnote-278-10\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-10\" class=\"return-footnote\" aria-label=\"Return to footnote 10\">&crarr;<\/a><\/li><li id=\"footnote-278-11\">\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2016_Occluded_Coronay_Arteries.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">2016 Occluded Coronay Arteries.jpg<\/a>\" by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax College<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 3.0<\/a> <a href=\"#return-footnote-278-11\" class=\"return-footnote\" aria-label=\"Return to footnote 11\">&crarr;<\/a><\/li><li id=\"footnote-278-12\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-12\" class=\"return-footnote\" aria-label=\"Return to footnote 12\">&crarr;<\/a><\/li><li id=\"footnote-278-13\">\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:A_man_having_a_Heart_Attack.png\" target=\"_blank\" rel=\"noopener noreferrer\">A man having a Heart Attack.png<\/a>\" by <a href=\"https:\/\/www.myupchar.com\/en\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.myupchar.com\/en<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by-sa\/4.0\/deed.en\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY-SA 4.0<\/a> <a href=\"#return-footnote-278-13\" class=\"return-footnote\" aria-label=\"Return to footnote 13\">&crarr;<\/a><\/li><li id=\"footnote-278-14\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-14\" class=\"return-footnote\" aria-label=\"Return to footnote 14\">&crarr;<\/a><\/li><li id=\"footnote-278-15\">This work is a derivative of <a href=\"https:\/\/openstax.org\/details\/books\/anatomy-and-physiology\" target=\"_blank\" rel=\"noopener noreferrer\">Anatomy and Physiology<\/a> by <a href=\"https:\/\/openstax.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">OpenStax<\/a> licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 4.0<\/a>. Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/1-introduction<\/a> <a href=\"#return-footnote-278-15\" class=\"return-footnote\" aria-label=\"Return to footnote 15\">&crarr;<\/a><\/li><li id=\"footnote-278-16\">\"<a href=\"https:\/\/www.flickr.com\/photos\/constructiondeal_marketing\/4254385133\" target=\"_blank\" rel=\"noopener noreferrer\">Stroke Diagram<\/a>\" by <a href=\"https:\/\/www.flickr.com\/photos\/constructiondeal_marketing\/4254385133\" target=\"_blank\" rel=\"noopener noreferrer\">ConstructionDealMkting<\/a> is licensed under <a href=\"https:\/\/creativecommons.org\/licenses\/by\/2.0\/\" target=\"_blank\" rel=\"noopener noreferrer\">CC BY 2.0<\/a> <a href=\"#return-footnote-278-16\" class=\"return-footnote\" aria-label=\"Return to footnote 16\">&crarr;<\/a><\/li><li id=\"footnote-278-17\">Anderson, P. &amp; Townsend, T. (2015) Preventing high-alert medication errors in hospital patients. <em>Nurse Today, 10<\/em>(5). <a href=\"https:\/\/www.americannursetoday.com\/wp-content\/uploads\/2015\/05\/ant5-CE-421.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.americannursetoday.com\/wp-content\/uploads\/2015\/05\/ant5-CE-421.pdf<\/a> <a href=\"#return-footnote-278-17\" class=\"return-footnote\" aria-label=\"Return to footnote 17\">&crarr;<\/a><\/li><li id=\"footnote-278-18\">\"<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:2024_Cardiac_Arrhythmias.jpg\" target=\"_blank\" rel=\"noopener noreferrer\">Common ECG Abnormalities<\/a>\" by <a href=\"https:\/\/cnx.org\/\" target=\"_blank\" rel=\"noopener noreferrer\">CNX OpenStax<\/a> is licensed under<a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\" target=\"_blank\" rel=\"noopener noreferrer\"> CC BY 4.0.<\/a> Access for free at <a href=\"https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/openstax.org\/books\/anatomy-and-physiology\/pages\/19-2-cardiac-muscle-and-electrical-activity<\/a> <a href=\"#return-footnote-278-18\" class=\"return-footnote\" aria-label=\"Return to footnote 18\">&crarr;<\/a><\/li><li id=\"footnote-278-19\">National Heart, Lung, and Blood, National Institute of Health (2019). <em>Heart failure.<\/em> <a href=\"https:\/\/www.nhlbi.nih.gov\/health-topics\/heart-failure\" target=\"_blank\" rel=\"noopener noreferrer\">https:\/\/www.nhlbi.nih.gov\/health-topics\/heart-failure<\/a> <a href=\"#return-footnote-278-19\" class=\"return-footnote\" aria-label=\"Return to footnote 19\">&crarr;<\/a><\/li><\/ol><\/div><div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_278_2715\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_278_2715\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_278_2807\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_278_2807\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_278_2722\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_278_2722\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_278_2724\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_278_2724\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close 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