Atherosclerosis is a pattern of the disease arteriosclerosis , characterized by development of abnormalities called lesions in walls of arteries . This is a chronic inflammatory disease involving many different cell types and driven by elevated levels of cholesterol in the blood. These lesions may lead to narrowing of the arterial walls due to buildup of atheromatous plaques . At the onset there are usually no symptoms, but if they develop, symptoms generally begin around middle age. In severe cases, it can result in coronary artery disease , stroke , peripheral artery disease , or kidney disorders , depending on which body part(s) the affected arteries are located in the body.
172-517: Cardiovascular disease ( CVD ) is any disease involving the heart or blood vessels . CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina , heart attack ), heart failure , hypertensive heart disease , rheumatic heart disease , cardiomyopathy , arrhythmia , congenital heart disease , valvular heart disease , carditis , aortic aneurysms , peripheral artery disease , thromboembolic disease , and venous thrombosis . The underlying mechanisms vary depending on
344-578: A 10 percent to 30 percent higher risk of cardiovascular disease. Sleep disorders such as sleep-disordered breathing and insomnia , are also associated with a higher cardiometabolic risk. An estimated 50 to 70 million Americans have insomnia, sleep apnea or other chronic sleep disorders . In addition, sleep research displays differences in race and class. Short sleep and poor sleep tend to be more frequently reported in ethnic minorities than in whites. African-Americans report experiencing short durations of sleep five times more often than whites, possibly as
516-626: A 35-40 hours week. A diet high in fruits and vegetables decreases the risk of cardiovascular disease and death . A 2021 review found that plant-based diets can provide a risk reduction for CVD if a healthy plant-based diet is consumed. Unhealthy plant-based diets do not provide benefits over diets including meat. A similar meta-analysis and systematic review also looked into dietary patterns and found "that diets lower in animal foods and unhealthy plant foods, and higher in healthy plant foods are beneficial for CVD prevention". A 2018 meta-analysis of observational studies concluded that "In most countries,
688-490: A beneficial effect. A diet high in trans fatty acids is associated with higher rates of cardiovascular disease, and in 2015 the Food and Drug Administration (FDA) determined that there was 'no longer a consensus among qualified experts that partially hydrogenated oils (PHOs), which are the primary dietary source of industrially produced trans fatty acids (IP-TFA), are generally recognized as safe (GRAS) for any use in human food'. There
860-472: A circular opening. If the enlargement is beyond proportion to the atheroma thickness, then an aneurysm is created. Although arteries are not typically studied microscopically, two plaque types can be distinguished: In effect, the muscular portion of the artery wall forms small aneurysms just large enough to hold the atheroma that are present. The muscular portion of artery walls usually remains strong, even after they have been remodeled to compensate for
1032-440: A crucial role in cardiac conduction. It arises from the lower part of the interventricular septum and crosses the interior space of the right ventricle to connect with the inferior papillary muscle. The right ventricle tapers into the pulmonary trunk , into which it ejects blood when contracting. The pulmonary trunk branches into the left and right pulmonary arteries that carry the blood to each lung. The pulmonary valve lies between
1204-532: A fatty streak. Foam cells eventually die and further propagate the inflammatory process. In addition to these cellular activities, there is also smooth muscle proliferation and migration from the tunica media into the intima in response to cytokines secreted by damaged endothelial cells. This causes the formation of a fibrous capsule covering the fatty streak. Intact endothelium can prevent this smooth muscle proliferation by releasing nitric oxide . Calcification forms among vascular smooth muscle cells of
1376-456: A figure 8 around the two ventricles and proceeding toward the apex. This complex swirling pattern allows the heart to pump blood more effectively. There are two types of cells in cardiac muscle: muscle cells which have the ability to contract easily, and pacemaker cells of the conducting system. The muscle cells make up the bulk (99%) of cells in the atria and ventricles. These contractile cells are connected by intercalated discs which allow
1548-606: A given age , from CVD are more common and have been increasing in much of the developing world , while rates have declined in most of the developed world since the 1970s. Coronary artery disease and stroke account for 80% of CVD deaths in males and 75% of CVD deaths in females. Most cardiovascular disease affects older adults. In the United States 11% of people between 20 and 40 have CVD, while 37% between 40 and 60, 71% of people between 60 and 80, and 85% of people over 80 have CVD. The average age of death from coronary artery disease in
1720-887: A greater risk of cardiovascular disease. Policies that have resulted in increased socio-economic inequalities have been associated with greater subsequent socio-economic differences in cardiovascular disease implying a cause and effect relationship. Psychosocial factors, environmental exposures, health behaviours, and health-care access and quality contribute to socio-economic differentials in cardiovascular disease. The Commission on Social Determinants of Health recommended that more equal distributions of power, wealth, education, housing, environmental factors, nutrition, and health care were needed to address inequalities in cardiovascular disease and non-communicable diseases. Particulate matter has been studied for its short- and long-term exposure effects on cardiovascular disease . Currently, airborne particles under 2.5 micrometers in diameter (PM 2.5 ) are
1892-438: A main left and a main right trunk, which travel up the groove between the ventricles that exists on the heart's surface, receiving smaller vessels as they travel up. These vessels then travel into the atrioventricular groove, and receive a third vessel which drains the section of the left ventricle sitting on the diaphragm. The left vessel joins with this third vessel, and travels along the pulmonary artery and left atrium, ending in
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#17331150394522064-493: A male with diabetes. Women who have high blood pressure and had complications in their pregnancy have three times the risk of developing cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy. Coronary heart diseases are 2 to 5 times more common among middle-aged men than women. In a study done by the World Health Organization , sex contributes to approximately 40% of
2236-400: A mass of 250–350 grams (9–12 oz). The heart is often described as the size of a fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness, although this description is disputed, as the heart is likely to be slightly larger. Well-trained athletes can have much larger hearts due to the effects of exercise on the heart muscle, similar to
2408-467: A peak rate of 165–185 bpm early in the early 7th week (early 9th week after the LMP). After 9 weeks (start of the fetal stage) it starts to decelerate, slowing to around 145 (±25) bpm at birth. There is no difference in female and male heart rates before birth. The heart functions as a pump in the circulatory system to provide a continuous flow of blood throughout the body. This circulation consists of
2580-652: A physician may resort to interventional or surgical procedures to correct the obstruction. Treatment of established disease may include medications to lower cholesterol such as statins , blood pressure medication , or medications that decrease clotting, such as aspirin . Many procedures may also be carried out such as percutaneous coronary intervention , coronary artery bypass graft , or carotid endarterectomy . Medical treatments often focus on alleviating symptoms. However, measures that focus on decreasing underlying atherosclerosis—as opposed to simply treating symptoms—are more effective. Non-pharmaceutical means are usually
2752-425: A posterior cusp. These cusps are also attached via chordae tendinae to two papillary muscles projecting from the ventricular wall. The papillary muscles extend from the walls of the heart to valves by cartilaginous connections called chordae tendinae. These muscles prevent the valves from falling too far back when they close. During the relaxation phase of the cardiac cycle, the papillary muscles are also relaxed and
2924-402: A primitive heart tube known as the tubular heart . Between the third and fourth week, the heart tube lengthens, and begins to fold to form an S-shape within the pericardium. This places the chambers and major vessels into the correct alignment for the developed heart. Further development will include the formation of the septa and the valves and the remodeling of the heart chambers. By the end of
3096-460: A rapid response to impulses of action potential from the pacemaker cells. The intercalated discs allow the cells to act as a syncytium and enable the contractions that pump blood through the heart and into the major arteries . The pacemaker cells make up 1% of cells and form the conduction system of the heart. They are generally much smaller than the contractile cells and have few myofibrils which gives them limited contractibility. Their function
3268-447: A reduction in cardiovascular events. A 2015 meta-analysis of observational studies however did not find a convincing association between saturated fat intake and cardiovascular disease. Variation in what is used as a substitute for saturated fat may explain some differences in findings. The benefit from replacement with polyunsaturated fats appears greatest, while replacement of saturated fats with carbohydrates does not appear to have
3440-500: A result of social and environmental factors. Black children and children living in disadvantaged neighborhoods have much higher rates of sleep apnea. Cardiovascular disease has a greater impact on low- and middle-income countries compared to those with higher income. Although data on the social patterns of cardiovascular disease in low- and middle-income countries is limited, reports from high-income countries consistently demonstrate that low educational status or income are associated with
3612-429: A risk of death as never smokers. Insufficient physical activity (defined as less than 5 x 30 minutes of moderate activity per week, or less than 3 x 20 minutes of vigorous activity per week) is currently the fourth leading risk factor for mortality worldwide. In 2008, 31.3% of adults aged 15 or older (28.2% men and 34.4% women) were insufficiently physically active. The risk of ischemic heart disease and diabetes mellitus
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#17331150394523784-435: A small amount compared to usual care. However, there was some uncertainty as to whether providing these scores had any effect on cardiovascular disease events. It is unclear whether or not dental care in those with periodontitis affects their risk of cardiovascular disease. According to a 2021 WHO study, working 55+ hours a week raises the risk of stroke by 35% and the risk of dying from heart conditions by 17%, when compared to
3956-402: A small amount of fluid . The wall of the heart is made up of three layers: epicardium , myocardium , and endocardium . In all vertebrates , the heart has an asymmetric orientation, almost always on the left side. According to one theory, this is caused by a developmental axial twist in the early embryo. The heart pumps blood with a rhythm determined by a group of pacemaker cells in
4128-455: A small effect. Age is the most important risk factor in developing cardiovascular or heart diseases, with approximately a tripling of risk with each decade of life. Coronary fatty streaks can begin to form in adolescence. It is estimated that 82 percent of people who die of coronary heart disease are 65 and older. Simultaneously, the risk of stroke doubles every decade after age 55. Multiple explanations are proposed to explain why age increases
4300-456: A thrombus that will rapidly slow or stop blood flow, leading to the death of the tissues fed by the artery in approximately five minutes. This event is called an infarction . Areas of severe narrowing, stenosis , detectable by angiography , and to a lesser extent " stress testing " have long been the focus of human diagnostic techniques for cardiovascular disease , in general. However, these methods focus on detecting only severe narrowing, not
4472-480: A valve closes the foramen ovale and establishes the typical cardiac circulation pattern. A depression in the surface of the right atrium remains where the foramen ovale was, called the fossa ovalis. The embryonic heart begins beating at around 22 days after conception (5 weeks after the last normal menstrual period, LMP). It starts to beat at a rate near to the mother's which is about 75–80 beats per minute (bpm). The embryonic heart rate then accelerates and reaches
4644-696: A vegan diet is associated with a more favourable cardio-metabolic profile compared to an omnivorous diet." Evidence suggests that the Mediterranean diet may improve cardiovascular outcomes. There is also evidence that a Mediterranean diet may be more effective than a low-fat diet in bringing about long-term changes to cardiovascular risk factors (e.g., lower cholesterol level and blood pressure ). The DASH diet (high in nuts, fish, fruits and vegetables, and low in sweets, red meat and fat) has been shown to reduce blood pressure, lower total and low density lipoprotein cholesterol and improve metabolic syndrome ; but
4816-408: Is a slow process, developed over several years through a complex series of cellular events occurring within the arterial wall and in response to several local vascular circulating factors. One recent hypothesis suggests that, for unknown reasons, leukocytes , such as monocytes or basophils , begin to attack the endothelium of the artery lumen in cardiac muscle . The ensuing inflammation leads to
4988-584: Is a sudden event that occurs specifically in atheromas with thinner/weaker fibrous caps that have become "unstable". Repeated plaque ruptures, ones not resulting in total lumen closure, combined with the clot patch over the rupture and healing response to stabilize the clot is the process that produces most stenoses over time. The stenotic areas often become more stable despite increased flow velocities at these narrowings. Most major blood-flow-stopping events occur at large plaques, which, before their rupture, produced little if any stenosis. From clinical trials, 20%
5160-402: Is also beneficial. Treating people who have strep throat with antibiotics can decrease the risk of rheumatic heart disease. The use of aspirin in people who are otherwise healthy is of unclear benefit. Cardiovascular diseases are the leading cause of death worldwide except Africa. Together CVD resulted in 17.9 million deaths (32.1%) in 2015, up from 12.3 million (25.8%) in 1990. Deaths, at
5332-1206: Is also linked to carotid artery thickening and increased risk of acute myocardial infarction. Existing cardiovascular disease or a previous cardiovascular event, such as a heart attack or stroke, is the strongest predictor of a future cardiovascular event. Age, sex, smoking, blood pressure, blood lipids and diabetes are important predictors of future cardiovascular disease in people who are not known to have cardiovascular disease. These measures, and sometimes others, may be combined into composite risk scores to estimate an individual's future risk of cardiovascular disease. Numerous risk scores exist although their respective merits are debated. Other diagnostic tests and biomarkers remain under evaluation but currently these lack clear-cut evidence to support their routine use. They include family history, coronary artery calcification score, high sensitivity C-reactive protein (hs-CRP), ankle–brachial pressure index , lipoprotein subclasses and particle concentration, lipoprotein(a), apolipoproteins A-I and B, fibrinogen , white blood cell count, homocysteine , N-terminal pro B-type natriuretic peptide (NT-proBNP), and markers of kidney function. High blood phosphorus
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5504-492: Is also linked to an increased risk. There is evidence that mental health problems, in particular depression and traumatic stress, is linked to cardiovascular diseases. Whereas mental health problems are known to be associated with risk factors for cardiovascular diseases such as smoking, poor diet, and a sedentary lifestyle, these factors alone do not explain the increased risk of cardiovascular diseases seen in depression, stress, and anxiety. Moreover, posttraumatic stress disorder
5676-419: Is associated with heart disease. Associations also exist for exposure to arsenic , benzopyrenes , lead , dynamite , carbon disulphide , carbon monoxide , metalworking fluids and occupational exposure to tobacco smoke . Working with the electrolytic production of aluminium or the production of paper when the sulphate pulping process is used is associated with heart disease. An association
5848-512: Is being electrolytically produced, is associated with stroke . As of 2017, evidence suggests that certain leukemia -associated mutations in blood cells may also lead to increased risk of cardiovascular disease. Several large-scale research projects looking at human genetic data have found a robust link between the presence of these mutations, a condition known as clonal hematopoiesis , and cardiovascular disease-related incidents and mortality. Radiation treatments (RT) for cancer can increase
6020-423: Is caused by marked narrowing or closure of arteries going to the brain; lack of adequate blood supply leads to the death of the cells of the affected tissue. Peripheral arteries , which supply blood to the legs, arms, and pelvis, also experience marked narrowing due to plaque rupture and clots. Symptoms of the narrowing are pain and numbness within the arms or legs. Another significant location for plaque formation
6192-404: Is combined with medication therapy. For example, statins help to lower cholesterol. Antiplatelet medications like aspirin help to prevent clots, and a variety of antihypertensive medications are routinely used to control blood pressure. If the combined efforts of risk factor modification and medication therapy are not sufficient to control symptoms or fight imminent threats of ischemic events,
6364-407: Is complex, and may depend on the amount of alcohol consumed. There is a direct relationship between high levels of drinking alcohol and cardiovascular disease. Drinking at low levels without episodes of heavy drinking may be associated with a reduced risk of cardiovascular disease, but there is evidence that associations between moderate alcohol consumption and protection from stroke are non-causal. At
6536-447: Is conflicting evidence concerning whether dietary supplements of omega-3 fatty acids (a type of polyunsaturated essential fatty acid) added to diet improve cardiovascular risk. The benefits of recommending a low-salt diet in people with high or normal blood pressure are not clear. In those with heart failure, after one study was left out, the rest of the trials show a trend to benefit. Another review of dietary salt concluded that there
6708-400: Is connected to the left ventricle by the mitral valve. The left ventricle is much thicker as compared with the right, due to the greater force needed to pump blood to the entire body. Like the right ventricle, the left also has trabeculae carneae , but there is no moderator band . The left ventricle pumps blood to the body through the aortic valve and into the aorta. Two small openings above
6880-404: Is created that travels through the heart, causing the heart muscle to contract. The sinoatrial node is found in the upper part of the right atrium near to the junction with the superior vena cava. The electrical signal generated by the sinoatrial node travels through the right atrium in a radial way that is not completely understood. It travels to the left atrium via Bachmann's bundle , such that
7052-432: Is disputed. The World Health Organization attributes approximately 1.7 million deaths worldwide to low fruit and vegetable consumption. Frequent consumption of high-energy foods, such as processed foods that are high in fats and sugars, promotes obesity and may increase cardiovascular risk. The amount of dietary salt consumed may also be an important determinant of blood pressure levels and overall cardiovascular risk. There
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7224-543: Is documented as increasing cardiovascular risk in both adults and teens. Recommendations suggest that infants typically need 12 or more hours of sleep per day, adolescents at least eight or nine hours, and adults seven or eight. About one-third of adult Americans get less than the recommended seven hours of sleep per night, and in a study of teenagers, just 2.2 percent of those studied got enough sleep, many of whom did not get good quality sleep. Studies have shown that short sleepers getting less than seven hours sleep per night have
7396-483: Is estimated to account for approximately 13% of CVD deaths, while tobacco accounts for 9%, diabetes 6%, lack of exercise 6%, and obesity 5%. Rheumatic heart disease may follow untreated strep throat . It is estimated that up to 90% of CVD may be preventable. Prevention of CVD involves improving risk factors through: healthy eating , exercise, avoidance of tobacco smoke and limiting alcohol intake. Treating risk factors, such as high blood pressure, blood lipids and diabetes
7568-409: Is evidence that higher consumption of sugar is associated with higher blood pressure and unfavorable blood lipids, and sugar intake also increases the risk of diabetes mellitus. High consumption of processed meats is associated with an increased risk of cardiovascular disease, possibly in part due to increased dietary salt intake. The relationship between alcohol consumption and cardiovascular disease
7740-425: Is generally by eating a healthy diet, exercising, not smoking, and maintaining a normal weight. Changes in diet may help prevent the development of atherosclerosis. Tentative evidence suggests that a diet containing dairy products has no effect on or decreases the risk of cardiovascular disease . A diet high in fruits and vegetables decreases the risk of cardiovascular disease and death. Evidence suggests that
7912-592: Is inconclusive. Additionally echocardiography , myocardial perfusion imaging , and cardiac stress testing is not recommended in those at low risk who do not have symptoms. Some biomarkers may add to conventional cardiovascular risk factors in predicting the risk of future cardiovascular disease; however, the value of some biomarkers is questionable. Ankle-brachial index (ABI), high-sensitivity C-reactive protein (hsCRP), and coronary artery calcium , are also of unclear benefit in those without symptoms as of 2018. The NIH recommends lipid testing in children beginning at
8084-487: Is independently associated with increased risk for incident coronary heart disease, even after adjusting for depression and other covariates. Little is known about the relationship between work and cardiovascular disease, but links have been established between certain toxins, extreme heat and cold, exposure to tobacco smoke, and mental health concerns such as stress and depression. A 2015 SBU-report looking at non-chemical factors found an association for those: Specifically
8256-428: Is located at the level of the third costal cartilage. The lower tip of the heart, the apex , lies to the left of the sternum (8 to 9 cm from the midsternal line ) between the junction of the fourth and fifth ribs near their articulation with the costal cartilages. The largest part of the heart is usually slightly offset to the left side of the chest ( levocardia ). In a rare congenital disorder ( dextrocardia )
8428-415: Is made of excess fat, collagen , and elastin . At first, as the plaques grow, only wall thickening occurs without narrowing. Stenosis is a late event, which may never occur and is often the result of repeated plaque rupture and healing responses, not just the atherosclerotic process. Early atherogenesis is characterized by the adherence of blood circulating monocytes (a type of white blood cell ) to
8600-493: Is moderate quality evidence that reducing saturated fat intake for at least two years reduces the risk of cardiovascular disease. High trans-fat intake has adverse effects on blood lipids and circulating inflammatory markers, and elimination of trans-fat from diets has been widely advocated. In 2018 the World Health Organization estimated that trans fats were the cause of more than half a million deaths per year. There
8772-566: Is more prevalent in men than women, atherosclerosis of the cerebral arteries and strokes equally affect both sexes. Marked narrowing in the coronary arteries, which are responsible for bringing oxygenated blood to the heart, can produce symptoms such as chest pain of angina and shortness of breath, sweating, nausea , dizziness or lightheadedness, breathlessness or palpitations . Abnormal heart rhythms called arrhythmias —the heart beating either too slowly or too quickly—are another consequence of ischemia . Carotid arteries supply blood to
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#17331150394528944-480: Is normalized to body size through body surface area and is called the cardiac index . The average cardiac output, using an average stroke volume of about 70mL, is 5.25 L/min, with a normal range of 4.0–8.0 L/min. The stroke volume is normally measured using an echocardiogram and can be influenced by the size of the heart, physical and mental condition of the individual, sex , contractility , duration of contraction, preload and afterload . Preload refers to
9116-616: Is not clear. Rabbits fed rancid fats develop atherosclerosis faster. Rats fed DHA -containing oils experienced marked disruptions to their antioxidant systems, and accumulated significant amounts of phospholipid hydroperoxide in their blood, livers and kidneys. Rabbits fed atherogenic diets containing various oils were found to undergo the most oxidative susceptibility of LDL via polyunsaturated oils. In another study, rabbits fed heated soybean oil "grossly induced atherosclerosis and marked liver damage were histologically and clinically demonstrated." However, Fred Kummerow claims that it
9288-413: Is not dietary cholesterol, but oxysterols , or oxidized cholesterols, from fried foods and smoking, that are the culprit. Rancid fats and oils taste very unpleasant in even small amounts, so people avoid eating them. It is very difficult to measure or estimate the actual human consumption of these substances. Highly unsaturated omega-3 rich oils such as fish oil, when being sold in pill form, can hide
9460-451: Is often done by the taking of a medical history , listening to the heart-sounds with a stethoscope , as well as with ECG , and echocardiogram which uses ultrasound . Specialists who focus on diseases of the heart are called cardiologists , although many specialties of medicine may be involved in treatment. The human heart is situated in the mediastinum , at the level of thoracic vertebrae T5 - T8 . A double-membraned sac called
9632-541: Is reduced by almost a third in adults who participate in 150 minutes of moderate physical activity each week (or equivalent). In addition, physical activity assists weight loss and improves blood glucose control, blood pressure, lipid profile and insulin sensitivity. These effects may, at least in part, explain its cardiovascular benefits. High dietary intakes of saturated fat, trans-fats and salt, and low intake of fruits, vegetables and fish are linked to cardiovascular risk, although whether all these associations indicate causes
9804-406: Is selectively required for the differentiation of monocytes to macrophages. The monocytes differentiate into macrophages , which proliferate locally, ingest oxidized LDL, slowly turning into large " foam cells " – so-called because of their changed appearance resulting from the numerous internal cytoplasmic vesicles and resulting high lipid content. Under the microscope, the lesion now appears as
9976-612: Is similar in many respects to neurons . Cardiac muscle tissue has autorhythmicity , the unique ability to initiate a cardiac action potential at a fixed rate—spreading the impulse rapidly from cell to cell to trigger the contraction of the entire heart. There are specific proteins expressed in cardiac muscle cells. These are mostly associated with muscle contraction, and bind with actin , myosin , tropomyosin , and troponin . They include MYH6 , ACTC1 , TNNI3 , CDH2 and PKP2 . Other proteins expressed are MYH7 and LDB3 that are also expressed in skeletal muscle. The pericardium
10148-451: Is some evidence that interventions aiming to reduce more than one cardiovascular risk factor may have beneficial effects on blood pressure, body mass index and waist circumference; however, evidence was limited and the authors were unable to draw firm conclusions on the effects on cardiovascular events and mortality. There is additional evidence to suggest that providing people with a cardiovascular disease risk score may reduce risk factors by
10320-464: Is strong evidence that high dietary salt intake increases blood pressure and worsens hypertension, and that it increases the number of cardiovascular disease events; both as a result of the increased blood pressure and probably through other mechanisms. Moderate evidence was found that high salt intake increases cardiovascular mortality; and some evidence was found for an increase in overall mortality, strokes, and left ventricular hypertrophy . Overall,
10492-411: Is the myocardial infarction or "heart attack". If the heart attack is not fatal, fibrous organization of the clot within the lumen ensues, covering the rupture but also producing stenosis or closure of the lumen, or over time and after repeated ruptures, resulting in a persistent, usually localized stenosis or blockage of the artery lumen. Stenoses can be slowly progressive, whereas plaque ulceration
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#173311503945210664-475: Is the myocardium (heart muscle) angina (cardiac chest pain) or myocardial infarction (heart attack) develops. The distribution of atherosclerotic plaques in a part of arterial endothelium is inhomogeneous. The multiple and focal development of atherosclerotic changes is similar to that in the development of amyloid plaques in the brain and age spots on the skin. Misrepair-accumulation aging theory suggests that misrepair mechanisms play an important role in
10836-459: Is the renal arteries , which supply blood to the kidneys. Plaque occurrence and accumulation lead to decreased kidney blood flow and chronic kidney disease , which, like in all other areas, is typically asymptomatic until late stages. In 2004, US data indicated that in ~66% of men and ~47% of women, the first symptom of atherosclerotic cardiovascular disease was a heart attack or sudden cardiac death (defined as death within one hour of onset of
11008-411: Is the average stenosis at plaques that subsequently rupture with resulting complete artery closure. Most severe clinical events do not occur at plaques that produce high-grade stenosis. From clinical trials, only 14% of heart attacks occur from artery closure at plaques producing a 75% or greater stenosis before the vessel closing. If the fibrous cap separating a soft atheroma from the bloodstream within
11180-402: Is the most life-threatening of the diabetic complications and diabetics are two- to four-fold more likely to die of cardiovascular-related causes than nondiabetics. Screening ECGs (either at rest or with exercise) are not recommended in those without symptoms who are at low risk. This includes those who are young without risk factors. In those at higher risk the evidence for screening with ECGs
11352-404: Is the sac that surrounds the heart. The tough outer surface of the pericardium is called the fibrous membrane. This is lined by a double inner membrane called the serous membrane that produces pericardial fluid to lubricate the surface of the heart. The part of the serous membrane attached to the fibrous membrane is called the parietal pericardium, while the part of the serous membrane attached to
11524-438: Is typically asymptomatic for decades because the arteries enlarge at all plaque locations, thus there is no effect on blood flow. Even most plaque ruptures do not produce symptoms until enough narrowing or closure of an artery, due to clots , occurs. Signs and symptoms only occur after severe narrowing or closure impedes blood flow to different organs enough to induce symptoms. Most of the time, patients realize that they have
11696-414: Is unknown and is proposed to be multifactorial. Risk factors include abnormal cholesterol levels , elevated levels of inflammatory biomarkers , high blood pressure , diabetes , smoking (both active and passive smoking ), obesity , genetic factors, family history, lifestyle habits, and an unhealthy diet. Plaque is made up of fat, cholesterol , immune cells, calcium , and other substances found in
11868-632: The American Diabetes Association , and the National Cholesterol Education Program make similar recommendations. In contrast, Prof Walter Willett (Harvard School of Public Health, PI of the second Nurses' Health Study ) recommends much higher levels of fat, especially of monounsaturated and polyunsaturated fat . These dietary recommendations reach a consensus, though, against consumption of trans fats . The role of eating oxidized fats ( rancid fats ) in humans
12040-498: The Frank-Starling mechanism . This states that the force of contraction is directly proportional to the initial length of muscle fiber, meaning a ventricle will contract more forcefully, the more it is stretched. Afterload , or how much pressure the heart must generate to eject blood at systole, is influenced by vascular resistance . It can be influenced by narrowing of the heart valves ( stenosis ) or contraction or relaxation of
12212-532: The Mediterranean diet may improve cardiovascular results. There is also evidence that a Mediterranean diet may be better than a low-fat diet in bringing about long-term changes to cardiovascular risk factors (e.g., lower cholesterol level and blood pressure ). A controlled exercise program combats atherosclerosis by improving the circulation and functionality of the vessels. Exercise is also used to manage weight in patients who are obese, lower blood pressure, and decrease cholesterol. Often lifestyle modification
12384-402: The beta–1 receptor . The heart is the first functional organ to develop and starts to beat and pump blood at about three weeks into embryogenesis . This early start is crucial for subsequent embryonic and prenatal development . The heart derives from splanchnopleuric mesenchyme in the neural plate which forms the cardiogenic region . Two endocardial tubes form here that fuse to form
12556-508: The blood . The narrowing of arteries limits the flow of oxygen-rich blood to parts of the body. Diagnosis is based upon a physical exam, electrocardiogram , and exercise stress test , among others. Prevention guidelines include eating a healthy diet , exercising, not smoking, and maintaining normal body weight. Treatment of established atherosclerotic disease may include medications to lower cholesterol such as statins , blood pressure medication , and anticoagulant therapies to reduce
12728-497: The circulatory system . The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to the lungs . In humans , the heart is approximately the size of a closed fist and is located between the lungs, in the middle compartment of the chest , called the mediastinum . In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right atria and lower left and right ventricles . Commonly,
12900-636: The coronary arteries . Cardiovascular disease in a person's parents increases their risk by ~3 fold, and genetics is an important risk factor for cardiovascular diseases. Genetic cardiovascular disease can occur either as a consequence of single variant (Mendelian) or polygenic influences. There are more than 40 inherited cardiovascular disease that can be traced to a single disease-causing DNA variant, although these conditions are rare. Most common cardiovascular diseases are non-Mendelian and are thought to be due to hundreds or thousands of genetic variants (known as single nucleotide polymorphisms), each associated with
13072-484: The coronary sinus , which is immediately above and to the middle of the opening of the inferior vena cava. In the wall of the right atrium is an oval-shaped depression known as the fossa ovalis , which is a remnant of an opening in the fetal heart known as the foramen ovale . Most of the internal surface of the right atrium is smooth, the depression of the fossa ovalis is medial, and the anterior surface has prominent ridges of pectinate muscles , which are also present in
13244-402: The endothelial cells of the vessel wall associated with retained low-density lipoprotein (LDL) particles. This retention may be a cause, an effect, or both, of the underlying inflammatory process. The presence of the plaque induces the muscle cells of the blood vessel to stretch, compensating for the additional bulk. The endothelial lining then thickens, increasing the separation between
13416-547: The endothelium and become oxidized, creating risk of cardiovascular disease . A complex set of biochemical reactions regulates the oxidation of LDL , involving enzymes (such as Lp-LpA2 ) and free radicals in the endothelium. Initial damage to the endothelium results in an inflammatory response. Monocytes enter the artery wall from the bloodstream, with platelets adhering to the area of insult. This may be promoted by redox signaling induction of factors such as VCAM-1 , which recruits circulating monocytes, and M-CSF , which
13588-405: The inferior tracheobronchial node . The right vessel travels along the right atrium and the part of the right ventricle sitting on the diaphragm. It usually then travels in front of the ascending aorta and then ends in a brachiocephalic node. The heart receives nerve signals from the vagus nerve and from nerves arising from the sympathetic trunk . These nerves act to influence, but not control,
13760-402: The pericardium surrounds the heart and attaches to the mediastinum. The back surface of the heart lies near the vertebral column , and the front surface known as the sternocostal surface sits behind the sternum and rib cartilages . The upper part of the heart is the attachment point for several large blood vessels—the venae cavae , aorta and pulmonary trunk . The upper part of the heart
13932-418: The posterior cardiac vein (draining the back of the left ventricle), the middle cardiac vein (draining the bottom of the left and right ventricles), and small cardiac veins . The anterior cardiac veins drain the front of the right ventricle and drain directly into the right atrium. Small lymphatic networks called plexuses exist beneath each of the three layers of the heart. These networks collect into
14104-430: The pulmonary artery . This has three cusps which are not attached to any papillary muscles. When the ventricle relaxes blood flows back into the ventricle from the artery and this flow of blood fills the pocket-like valve, pressing against the cusps which close to seal the valve. The semilunar aortic valve is at the base of the aorta and also is not attached to papillary muscles. This too has three cusps which close with
14276-404: The right atrial appendage , or auricle, and another in the upper left atrium, the left atrial appendage . The right atrium and the right ventricle together are sometimes referred to as the right heart . Similarly, the left atrium and the left ventricle together are sometimes referred to as the left heart . The ventricles are separated from each other by the interventricular septum , visible on
14448-411: The right atrial appendage . The right atrium is connected to the right ventricle by the tricuspid valve. The walls of the right ventricle are lined with trabeculae carneae , ridges of cardiac muscle covered by endocardium. In addition to these muscular ridges, a band of cardiac muscle, also covered by endocardium, known as the moderator band reinforces the thin walls of the right ventricle and plays
14620-463: The sinoatrial node , a group of pacemaking cells found in the wall of the right atrium. Cells in the sinoatrial node do this by creating an action potential . The cardiac action potential is created by the movement of specific electrolytes into and out of the pacemaker cells. The action potential then spreads to nearby cells. When the sinoatrial cells are resting, they have a negative charge on their membranes. A rapid influx of sodium ions causes
14792-497: The sinoatrial node . These generate an electric current that causes the heart to contract, traveling through the atrioventricular node and along the conduction system of the heart . In humans, deoxygenated blood enters the heart through the right atrium from the superior and inferior venae cavae and passes to the right ventricle. From here, it is pumped into pulmonary circulation to the lungs , where it receives oxygen and gives off carbon dioxide. Oxygenated blood then returns to
14964-405: The superior and inferior venae cavae . Blood collects in the right and left atrium continuously. The superior vena cava drains blood from above the diaphragm and empties into the upper back part of the right atrium. The inferior vena cava drains the blood from below the diaphragm and empties into the back part of the atrium below the opening for the superior vena cava. Immediately above and to
15136-458: The systemic circulation to and from the body and the pulmonary circulation to and from the lungs. Blood in the pulmonary circulation exchanges carbon dioxide for oxygen in the lungs through the process of respiration . The systemic circulation then transports oxygen to the body and returns carbon dioxide and relatively deoxygenated blood to the heart for transfer to the lungs. The right heart collects deoxygenated blood from two large veins,
15308-450: The accumulation of misrepairs of endothelium is focalized and self-accelerating. In this way, the growth of a plaque is also self-accelerating. Within a part of the arterial wall, the oldest plaque is always the biggest and is the most dangerous one to cause blockage of a local artery. The plaque is divided into three distinct components: Apart from thromboembolism, chronically expanding atherosclerotic lesions can cause complete closure of
15480-417: The age of 2 if there is a family history of heart disease or lipid problems. It is hoped that early testing will improve lifestyle factors in those at risk such as diet and exercise. Screening and selection for primary prevention interventions has traditionally been done through absolute risk using a variety of scores (ex. Framingham or Reynolds risk scores). This stratification has separated people who receive
15652-440: The age of 65. It is the number one cause of death and disability in developed countries . Though it was first described in 1575, there is evidence suggesting that this disease state is genetically inherent in the broader human population, with its origins tracing back to genetic mutations that may have occurred more than two million years ago during the evolution of hominin ancestors of modern human beings. Atherosclerosis
15824-400: The anatomy of the arteries that supply the heart The arteries divide at their furthest reaches into smaller branches that join at the edges of each arterial distribution. The coronary sinus is a large vein that drains into the right atrium, and receives most of the venous drainage of the heart. It receives blood from the great cardiac vein (receiving the left atrium and both ventricles),
15996-400: The aorta into two vessels, the left anterior descending and the left circumflex artery . The left anterior descending artery supplies heart tissue and the front, outer side, and septum of the left ventricle. It does this by branching into smaller arteries—diagonal and septal branches. The left circumflex supplies the back and underneath of the left ventricle. The right coronary artery supplies
16168-402: The aortic and pulmonary valves close. The ventricles start to relax, the mitral and tricuspid valves open, and the cycle begins again. Cardiac output (CO) is a measurement of the amount of blood pumped by each ventricle (stroke volume) in one minute. This is calculated by multiplying the stroke volume (SV) by the beats per minute of the heart rate (HR). So that: CO = SV x HR. The cardiac output
16340-409: The aortic and pulmonary valves open. Blood is ejected from the heart, causing the pressure within the ventricles to fall. Simultaneously, the atria refill as blood flows into the right atrium through the superior and inferior vena cavae , and into the left atrium through the pulmonary veins. Finally, when the pressure within the ventricles falls below the pressure within the aorta and pulmonary arteries,
16512-403: The aortic valve carry blood to the heart muscle ; the left coronary artery is above the left cusp of the valve, and the right coronary artery is above the right cusp. The heart wall is made up of three layers: the inner endocardium , middle myocardium and outer epicardium . These are surrounded by a double-membraned sac called the pericardium. The innermost layer of the heart is called
16684-441: The artery ruptures, tissue fragments are exposed and released. These tissue fragments are very clot-promoting, containing collagen and tissue factor ; they activate platelets and activate the system of coagulation . The result is the formation of a thrombus (blood clot) overlying the atheroma, which obstructs blood flow acutely. With the obstruction of blood flow, downstream tissues are starved of oxygen and nutrients. If this
16856-628: The atheromatous plaques. However, atheromas within the vessel wall are soft and fragile with little elasticity. Arteries constantly expand and contract with each heartbeat, i.e., the pulse. In addition, the calcification deposits between the outer portion of the atheroma and the muscular wall, as they progress, lead to a loss of elasticity and stiffening of the artery as a whole. The calcification deposits, after they have become sufficiently advanced, are partially visible on coronary artery computed tomography or electron beam tomography (EBT) as rings of increased radiographic density, forming halos around
17028-434: The atria, and the interventricular septum separates the ventricles. The interventricular septum is much thicker than the interatrial septum since the ventricles need to generate greater pressure when they contract. The heart has four valves, which separate its chambers. One valve lies between each atrium and ventricle, and one valve rests at the exit of each ventricle. The valves between the atria and ventricles are called
17200-450: The atrioventricular node only. The signal then travels along the bundle of His to left and right bundle branches through to the ventricles of the heart. In the ventricles the signal is carried by specialized tissue called the Purkinje fibers which then transmit the electric charge to the heart muscle. The normal resting heart rate is called the sinus rhythm , created and sustained by
17372-443: The atrioventricular valves. Between the right atrium and the right ventricle is the tricuspid valve . The tricuspid valve has three cusps, which connect to chordae tendinae and three papillary muscles named the anterior, posterior, and septal muscles, after their relative positions. The mitral valve lies between the left atrium and left ventricle. It is also known as the bicuspid valve due to its having two cusps, an anterior and
17544-415: The blood is pumped into the pulmonary trunk through the pulmonary valve. The pulmonary trunk divides into pulmonary arteries and progressively smaller arteries throughout the lungs, until it reaches capillaries . As these pass by alveoli carbon dioxide is exchanged for oxygen. This happens through the passive process of diffusion . In the left heart , oxygenated blood is returned to the left atrium via
17716-399: The brain and neck. Marked narrowing of the carotid arteries can present with symptoms such as a feeling of weakness; being unable to think straight; difficulty speaking; dizziness; difficulty in walking or standing up straight; blurred vision; numbness of the face, arms and legs; severe headache; and loss of consciousness. These symptoms are also related to stroke (death of brain cells). Stroke
17888-474: The cell only once it has a sufficiently high charge, and so are called voltage-gated . Shortly after this, the calcium channels close and potassium channels open, allowing potassium to leave the cell. This causes the cell to have a negative resting charge and is called repolarisation . When the membrane potential reaches approximately −60 mV, the potassium channels close and the process may begin again. Atherosclerosis The exact cause of atherosclerosis
18060-436: The coronary circulation, which includes arteries , veins , and lymphatic vessels . Blood flow through the coronary vessels occurs in peaks and troughs relating to the heart muscle's relaxation or contraction. Heart tissue receives blood from two arteries which arise just above the aortic valve. These are the left main coronary artery and the right coronary artery . The left main coronary artery splits shortly after leaving
18232-431: The current body of scientific evidence is uncertain on whether intermittent fasting could prevent cardiovascular disease. Intermittent fasting may help people lose more weight than regular eating patterns, but was not different from energy restriction diets. Heart The heart is a muscular organ found in most animals . This organ pumps blood through the blood vessels . Heart and blood vessels together make
18404-849: The developed world is around 80, while it is around 68 in the developing world. CVD is typically diagnosed seven to ten years earlier in men than in women. There are many cardiovascular diseases involving the blood vessels. They are known as vascular diseases . There are also many cardiovascular diseases that involve the heart. There are many risk factors for heart diseases: age, sex, tobacco use, physical inactivity, non-alcoholic fatty liver disease , excessive alcohol consumption, unhealthy diet, obesity, genetic predisposition and family history of cardiovascular disease, raised blood pressure ( hypertension ), raised blood sugar ( diabetes mellitus ), raised blood cholesterol ( hyperlipidemia ), undiagnosed celiac disease , psychosocial factors, poverty and low educational status, air pollution , and poor sleep . While
18576-449: The disease only when they experience other cardiovascular disorders such as stroke or heart attack . These symptoms, however, still vary depending on which artery or organ is affected. Early atherosclerotic processes likely begin in childhood. Fibrous and gelatinous lesions have been observed in the coronary arteries of children. Fatty streaks have been observed in the coronary arteries of juveniles. While coronary artery disease
18748-405: The disease process tends to be slowly progressive over decades, it usually remains asymptomatic until an atheroma ulcerates , which leads to immediate blood clotting at the site of the atheroma ulcer. This triggers a cascade of events that leads to clot enlargement, which may quickly obstruct blood flow. A complete blockage leads to ischemia of the myocardial (heart) muscle and damage. This process
18920-420: The disease. It is estimated that dietary risk factors are associated with 53% of CVD deaths. Coronary artery disease, stroke, and peripheral artery disease involve atherosclerosis . This may be caused by high blood pressure , smoking , diabetes mellitus , lack of exercise , obesity , high blood cholesterol , poor diet, excessive alcohol consumption, and poor sleep , among other things. High blood pressure
19092-403: The endocardium. It is made up of a lining of simple squamous epithelium and covers heart chambers and valves. It is continuous with the endothelium of the veins and arteries of the heart, and is joined to the myocardium with a thin layer of connective tissue. The endocardium, by secreting endothelins , may also play a role in regulating the contraction of the myocardium. The middle layer of
19264-401: The fatty deposits and the artery lining (the intima ). These capped fatty deposits (now called 'atheromas') produce enzymes that cause the artery to enlarge over time. As long as the artery enlarges sufficiently to compensate for the extra thickness of the atheroma, then no narrowing (" stenosis ") of the opening ("lumen") occurs. The artery expands with an egg-shaped cross-section, still with
19436-476: The female lipid metabolism toward a more atherogenic form by decreasing the HDL cholesterol level while increasing LDL and total cholesterol levels. Among men and women, there are differences in body weight, height, body fat distribution, heart rate, stroke volume, and arterial compliance. In the very elderly, age-related large artery pulsatility and stiffness are more pronounced among women than men. This may be caused by
19608-438: The fifth week, the septa are complete, and by the ninth week, the heart valves are complete. Before the fifth week, there is an opening in the fetal heart known as the foramen ovale . The foramen ovale allowed blood in the fetal heart to pass directly from the right atrium to the left atrium, allowing some blood to bypass the lungs. Within seconds after birth, a flap of tissue known as the septum primum that previously acted as
19780-417: The filling pressure of the atria at the end of diastole, when the ventricles are at their fullest. A main factor is how long it takes the ventricles to fill: if the ventricles contract more frequently, then there is less time to fill and the preload will be less. Preload can also be affected by a person's blood volume. The force of each contraction of the heart muscle is proportional to the preload, described as
19952-487: The first method of treatment, such as stopping smoking and practicing regular exercise. If these methods do not work, medicines are usually the next step in treating cardiovascular diseases and, with improvements, have increasingly become the most effective method over the long term. The key to the more effective approaches is to combine different treatment strategies. In addition, for those approaches, such as lipoprotein transport behaviors, which have been shown to produce
20124-533: The focal development of atherosclerosis. The development of a plaque is a result of the repair of the injured endothelium. Because of the infusion of lipids into the sub-endothelium, the repair has to end up with altered remodeling of the local endothelium. This is the manifestation of a misrepair. This altered remodeling increases the susceptibility of the local endothelium to damage and reduces its repair efficiency. Consequently, this part of endothelium has an increased risk of being injured and improperly repaired. Thus,
20296-478: The force of contraction are "positive" inotropes, and include sympathetic agents such as adrenaline , noradrenaline and dopamine . "Negative" inotropes decrease the force of contraction and include calcium channel blockers . The normal rhythmical heart beat, called sinus rhythm , is established by the heart's own pacemaker, the sinoatrial node (also known as the sinus node or the SA node). Here an electrical signal
20468-439: The formation of atheromatous plaques in the arterial tunica intima , a region of the vessel wall located between the endothelium and the tunica media . Chronic inflammation within the arterial wall, driven by immune cells like macrophages, accelerates atherosclerotic plaque instability by promoting collagen breakdown and thinning the fibrous cap, which increases the likelihood of rupture and thrombosis. The bulk of these lesions
20640-593: The heart called the cardiac plexus . The vagus nerve is a long, wandering nerve that emerges from the brainstem and provides parasympathetic stimulation to a large number of organs in the thorax and abdomen, including the heart. The nerves from the sympathetic trunk emerge through the T1–T4 thoracic ganglia and travel to both the sinoatrial and atrioventricular nodes, as well as to the atria and ventricles. The ventricles are more richly innervated by sympathetic fibers than parasympathetic fibers. Sympathetic stimulation causes
20812-406: The heart is known as the visceral pericardium. The pericardium is present in order to lubricate its movement against other structures within the chest, to keep the heart's position stabilised within the chest, and to protect the heart from infection. Heart tissue, like all cells in the body, needs to be supplied with oxygen , nutrients and a way of removing metabolic wastes . This is achieved by
20984-414: The heart is offset to the right side and is felt to be on the left because the left heart is stronger and larger, since it pumps to all body parts. Because the heart is between the lungs , the left lung is smaller than the right lung and has a cardiac notch in its border to accommodate the heart. The heart is cone-shaped, with its base positioned upwards and tapering down to the apex. An adult heart has
21156-413: The heart rate. Sympathetic nerves also influence the force of heart contraction. Signals that travel along these nerves arise from two paired cardiovascular centres in the medulla oblongata . The vagus nerve of the parasympathetic nervous system acts to decrease the heart rate, and nerves from the sympathetic trunk act to increase the heart rate. These nerves form a network of nerves that lies over
21328-414: The heart wall is the myocardium, which is the cardiac muscle —a layer of involuntary striated muscle tissue surrounded by a framework of collagen . The cardiac muscle pattern is elegant and complex, as the muscle cells swirl and spiral around the chambers of the heart, with the outer muscles forming a figure 8 pattern around the atria and around the bases of the great vessels and the inner muscles, forming
21500-526: The individual contribution of each risk factor varies between different communities or ethnic groups the overall contribution of these risk factors is very consistent. Some of these risk factors, such as age, sex or family history/genetic predisposition, are immutable; however, many important cardiovascular risk factors are modifiable by lifestyle change, social change, drug treatment (for example prevention of hypertension, hyperlipidemia, and diabetes). People with obesity are at increased risk of atherosclerosis of
21672-461: The intermediate and low risk groups. As a result, future preventative screening appears to shift toward applying prevention according to randomized trial results of each intervention rather than large-scale risk assessment. Up to 90% of cardiovascular disease may be preventable if established risk factors are avoided. Currently practised measures to prevent cardiovascular disease include: Most guidelines recommend combining preventive strategies. There
21844-432: The lack of oxygen supply to nearby cells, resulting in necrosis . The narrowing or obstruction of blood flow can occur in any artery within the body. Obstruction of arteries supplying the heart muscle results in a heart attack , while the obstruction of arteries supplying the brain results in an ischaemic stroke . Lumen stenosis that is greater than 75% was considered the hallmark of clinically significant disease in
22016-868: The late 1990s onwards. Besides the traditional diagnostic methods such as angiography and stress-testing, other detection techniques have been developed in the past decades for earlier detection of atherosclerotic disease. Some of the detection approaches include anatomical detection and physiologic measurement. Examples of anatomical detection methods include coronary calcium scoring by CT , carotid IMT ( intimal media thickness ) measurement by ultrasound, and intravascular ultrasound (IVUS). Examples of physiologic measurement methods include lipoprotein subclass analysis, HbA1c , hs-CRP , and homocysteine . Both anatomic and physiologic methods allow early detection before symptoms show up, disease staging, and tracking of disease progression. Anatomic methods are more expensive and some of them are invasive in nature, such as IVUS. On
22188-473: The left atrium, passes through the left ventricle and is pumped out through the aorta into systemic circulation , traveling through arteries , arterioles , and capillaries —where nutrients and other substances are exchanged between blood vessels and cells, losing oxygen and gaining carbon dioxide—before being returned to the heart through venules and veins . The heart beats at a resting rate close to 72 beats per minute. Exercise temporarily increases
22360-417: The lesion breaks, usually at the shoulder of the fibrous cap that separates the lesion from the arterial lumen, where the exposed thrombogenic components of the plaque, mainly collagen , will trigger thrombus formation. The thrombus then travels downstream to other blood vessels, where the blood clot may partially or completely block blood flow. If the blood flow is completely blocked, cell deaths occur due to
22532-424: The lifestyle interventions (generally lower and intermediate risk) from the medication (higher risk). The number and variety of risk scores available for use has multiplied, but their efficacy according to a 2016 review was unclear due to lack of external validation or impact analysis. Risk stratification models often lack sensitivity for population groups and do not account for the large number of negative events among
22704-610: The long-term benefits have been questioned. A high- fiber diet is associated with lower risks of cardiovascular disease. Worldwide, dietary guidelines recommend a reduction in saturated fat , and although the role of dietary fat in cardiovascular disease is complex and controversial there is a long-standing consensus that replacing saturated fat with unsaturated fat in the diet is sound medical advice. Total fat intake has not been found to be associated with cardiovascular risk. A 2020 systematic review found moderate quality evidence that reducing saturated fat intake for at least 2 years caused
22876-453: The loss of arterial elasticity and reduced arterial compliance and may subsequently lead to coronary artery disease. Men are at greater risk of heart disease than pre-menopausal women. Once past menopause , it has been argued that a woman's risk is similar to a man's although more recent data from the WHO and UN disputes this. If a female has diabetes, she is more likely to develop heart disease than
23048-400: The lumen. Chronically expanding lesions are often asymptomatic until the lumen stenosis is so severe (usually over 80%) that blood supply to downstream tissue(s) is insufficient, resulting in ischemia . These complications of advanced atherosclerosis are chronic, slowly progressive, and cumulative. Most commonly, soft plaque suddenly ruptures (see vulnerable plaque ), causing the formation of
23220-594: The major focus, in which gradients are used to determine CVD risk. Overall, long-term PM exposure increased rate of atherosclerosis and inflammation. In regards to short-term exposure (2 hours), every 25 μg/m of PM 2.5 resulted in a 48% increase of CVD mortality risk. In addition, after only 5 days of exposure, a rise in systolic (2.8 mmHg) and diastolic (2.7 mmHg) blood pressure occurred for every 10.5 μg/m of PM 2.5 . Other research has implicated PM 2.5 in irregular heart rhythm, reduced heart rate variability (decreased vagal tone), and most notably heart failure. PM 2.5
23392-503: The major precursor of cardiovascular disease, begins in childhood. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study demonstrated that intimal lesions appear in all the aortas and more than half of the right coronary arteries of youths aged 7–9 years. Obesity and diabetes mellitus are linked to cardiovascular disease, as are a history of chronic kidney disease and hypercholesterolaemia . In fact, cardiovascular disease
23564-413: The membrane's charge to become positive; this is called depolarisation and occurs spontaneously. Once the cell has a sufficiently high charge, the sodium channels close and calcium ions then begin to enter the cell, shortly after which potassium begins to leave it. All the ions travel through ion channels in the membrane of the sinoatrial cells. The potassium and calcium start to move out of and into
23736-419: The middle of the opening of the inferior vena cava is the opening of the thin-walled coronary sinus. Additionally, the coronary sinus returns deoxygenated blood from the myocardium to the right atrium. The blood collects in the right atrium. When the right atrium contracts, the blood is pumped through the tricuspid valve into the right ventricle. As the right ventricle contracts, the tricuspid valve closes and
23908-419: The muscles of the left and right atria contract together. The signal then travels to the atrioventricular node . This is found at the bottom of the right atrium in the atrioventricular septum , the boundary between the right atrium and the left ventricle. The septum is part of the cardiac skeleton , tissue within the heart that the electrical signal cannot pass through, which forces the signal to pass through
24080-464: The ongoing inflammatory process. The process is worsened if it is insufficient high-density lipoprotein (HDL), the lipoprotein particle that removes cholesterol from tissues and carries it back to the liver. The foam cells and platelets encourage the migration and proliferation of smooth muscle cells, which in turn ingest lipids, become replaced by collagen , and transform into foam cells themselves. A protective fibrous cap normally forms between
24252-572: The other hand, physiologic methods are often less expensive and safer. But they do not quantify the current state of the disease or directly track progression. In recent years, developments in nuclear imaging techniques such as PET and SPECT have provided ways of estimating the severity of atherosclerotic plaques. Up to 90% of cardiovascular disease may be preventable if established risk factors are avoided. Medical management of atherosclerosis first involves modification to risk factors–for example, via smoking cessation and diet restrictions. Prevention
24424-477: The outer edges of the atheromatous plaques, within the artery wall. On CT, >130 units on the Hounsfield scale (some argue for 90 units) has been the radiographic density usually accepted as clearly representing tissue calcification within arteries. These deposits demonstrate unequivocal evidence of the disease, relatively advanced, even though the lumen of the artery is often still normal by angiography. Although
24596-471: The past because recurring episodes of angina and abnormalities in stress tests are only detectable at that particular severity of stenosis. However, clinical trials have shown that only about 14% of clinically debilitating events occur at sites with more than 75% stenosis. Most cardiovascular events that involve sudden rupture of the atheroma plaque do not display any evident luminal narrowing. Thus, greater attention has been focused on "vulnerable plaque" from
24768-400: The peripheral blood vessels. The strength of heart muscle contractions controls the stroke volume. This can be influenced positively or negatively by agents termed inotropes . These agents can be a result of changes within the body, or be given as drugs as part of treatment for a medical disorder, or as a form of life support , particularly in intensive care units . Inotropes that increase
24940-448: The picture of an early phase of arteriosclerosis, appears to be induced by many drugs that have an antiproliferative mechanism of action ( Rainer Liedtke 2008). Cholesterol is delivered into the vessel wall by cholesterol-containing low-density lipoprotein (LDL) particles. To attract and stimulate macrophages, the cholesterol must be released from the LDL particles and oxidized, a key step in
25112-417: The plaque and lumen. The thickening somewhat offsets the narrowing caused by the growth of the plaque, but moreover, it causes the wall to stiffen and become less compliant to stretching with each heartbeat. The relation between dietary fat and atherosclerosis is controversial. The USDA , in its food pyramid , promotes a diet of about 64% carbohydrates from total calories. The American Heart Association ,
25284-415: The population level, the health risks of drinking alcohol exceed any potential benefits. Untreated celiac disease can cause the development of many types of cardiovascular diseases, most of which improve or resolve with a gluten-free diet and intestinal healing. However, delays in recognition and diagnosis of celiac disease can cause irreversible heart damage. A lack of good sleep, in amount or quality,
25456-414: The pressure of the blood flowing back from the aorta. The right heart consists of two chambers, the right atrium and the right ventricle, separated by a valve, the tricuspid valve . The right atrium receives blood almost continuously from the body's two major veins , the superior and inferior venae cavae . A small amount of blood from the coronary circulation also drains into the right atrium via
25628-515: The pulmonary veins. It is then pumped into the left ventricle through the mitral valve and into the aorta through the aortic valve for systemic circulation. The aorta is a large artery that branches into many smaller arteries, arterioles , and ultimately capillaries. In the capillaries, oxygen and nutrients from blood are supplied to body cells for metabolism, and exchanged for carbon dioxide and waste products. Capillary blood, now deoxygenated, travels into venules and veins that ultimately collect in
25800-587: The rate, but lowers it in the long term, and is good for heart health. Cardiovascular diseases are the most common cause of death globally as of 2008, accounting for 30% of all human deaths. Of these more than three-quarters are a result of coronary artery disease and stroke . Risk factors include: smoking , being overweight , little exercise, high cholesterol , high blood pressure , and poorly controlled diabetes , among others. Cardiovascular diseases do not frequently have symptoms but may cause chest pain or shortness of breath . Diagnosis of heart disease
25972-422: The release of the neurotransmitter norepinephrine (also known as noradrenaline ) at the neuromuscular junction of the cardiac nerves . This shortens the repolarisation period, thus speeding the rate of depolarisation and contraction, which results in an increased heart rate. It opens chemical or ligand-gated sodium and calcium ion channels, allowing an influx of positively charged ions . Norepinephrine binds to
26144-427: The response of skeletal muscle. The heart has four chambers, two upper atria , the receiving chambers, and two lower ventricles , the discharging chambers. The atria open into the ventricles via the atrioventricular valves , present in the atrioventricular septum . This distinction is visible also on the surface of the heart as the coronary sulcus . There is an ear-shaped structure in the upper right atrium called
26316-420: The right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart . Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. In a healthy heart, blood flows one way through the heart due to heart valves , which prevent backflow . The heart is enclosed in a protective sac, the pericardium , which also contains
26488-424: The right atrium, right ventricle, and lower posterior sections of the left ventricle. The right coronary artery also supplies blood to the atrioventricular node (in about 90% of people) and the sinoatrial node (in about 60% of people). The right coronary artery runs in a groove at the back of the heart and the left anterior descending artery runs in a groove at the front. There is significant variation between people in
26660-414: The right heart and the pulmonary trunk. The left heart has two chambers: the left atrium and the left ventricle, separated by the mitral valve . The left atrium receives oxygenated blood back from the lungs via one of the four pulmonary veins . The left atrium has an outpouching called the left atrial appendage . Like the right atrium, the left atrium is lined by pectinate muscles . The left atrium
26832-440: The risk of stroke was also increased by exposure to ionizing radiation. Hypertension develops more often in those who experience job strain and who have shift-work. Differences between women and men in risk are small, however men risk having and dying of heart attacks or stroke twice as often as women during working life. A 2017 SBU report found evidence that workplace exposure to silica dust , engine exhaust or welding fumes
27004-469: The risk of blood clot formation. As the disease state progresses more invasive strategies are applied such as percutaneous coronary intervention , coronary artery bypass graft , or carotid endarterectomy . Genetic factors are also strongly implicated in the disease process; it is unlikely to be entirely based on lifestyle choices. Atherosclerosis generally starts when a person is young and worsens with age. Almost all people are affected to some degree by
27176-421: The risk of cardiovascular/heart diseases. One of them relates to serum cholesterol level. In most populations, the serum total cholesterol level increases as age increases. In men, this increase levels off around age 45 to 50 years. In women, the increase continues sharply until age 60 to 65 years. Aging is also associated with changes in the mechanical and structural properties of the vascular wall, which leads to
27348-948: The risk of heart disease and death, as observed in breast cancer therapy. Therapeutic radiation increases the risk of a subsequent heart attack or stroke by 1.5 to 4 times; the increase depends on the dose strength, volume, and location. Use of concomitant chemotherapy, e.g. anthracyclines, is an aggravating risk factor. The occurrence rate of RT induced cardiovascular disease is estimated between 10% and 30%. Side-effects from radiation therapy for cardiovascular diseases have been termed radiation-induced heart disease or radiation-induced cardiovascular disease . Symptoms are dose-dependent and include cardiomyopathy , myocardial fibrosis , valvular heart disease , coronary artery disease , heart arrhythmia and peripheral artery disease . Radiation-induced fibrosis, vascular cell damage and oxidative stress can lead to these and other late side-effect symptoms. Population-based studies show that atherosclerosis,
27520-471: The superior and inferior vena cavae, and into the right heart. The cardiac cycle is the sequence of events in which the heart contracts and relaxes with every heartbeat. The period of time during which the ventricles contract, forcing blood out into the aorta and main pulmonary artery, is known as systole , while the period during which the ventricles relax and refill with blood is known as diastole . The atria and ventricles work in concert, so in systole when
27692-511: The surface of the heart as the anterior longitudinal sulcus and the posterior interventricular sulcus . The fibrous cardiac skeleton gives structure to the heart. It forms the atrioventricular septum, which separates the atria from the ventricles, and the fibrous rings, which serve as bases for the four heart valves . The cardiac skeleton also provides an important boundary in the heart's electrical conduction system since collagen cannot conduct electricity . The interatrial septum separates
27864-452: The surrounding muscular layer, specifically in the muscle cells adjacent to atheromas and on the surface of atheroma plaques and tissue. In time, as cells die, this leads to extracellular calcium deposits between the muscular wall and outer portion of the atheromatous plaques. With the atheromatous plaque interfering with the regulation of calcium deposition, it accumulates and crystallizes. A similar form of intramural calcification, presenting
28036-587: The symptom). Case studies have included autopsies of U.S. soldiers killed in World War II and the Korean War . A much-cited report involved the autopsies of 300 U.S. soldiers killed in Korea. Although the average age of the men was 22.1 years, 77.3 percent had "gross evidence of coronary arteriosclerosis". The atherosclerotic process is not well understood. Atherosclerosis is associated with inflammatory processes in
28208-553: The taste of oxidized or rancid fat that might be present. In the US, the health food industry's dietary supplements are self-regulated and outside of FDA regulations. To protect unsaturated fats from oxidation, it is best to keep them cool and in oxygen-free environments. Atherogenesis is the developmental process of atheromatous plaques . It is characterized by a remodeling of arteries leading to subendothelial accumulation of fatty substances called plaques. The buildup of an atheromatous plaque
28380-408: The tension on the chordae tendineae is slight. As the heart chambers contract, so do the papillary muscles. This creates tension on the chordae tendineae, helping to hold the cusps of the atrioventricular valves in place and preventing them from being blown back into the atria. Two additional semilunar valves sit at the exit of each of the ventricles. The pulmonary valve is located at the base of
28552-451: The underlying atherosclerosis disease. As demonstrated by human clinical studies, most severe events occur in locations with heavy plaque, yet little or no lumen narrowing present before debilitating events suddenly occur. Plaque rupture can lead to artery lumen occlusion within seconds to minutes, potential permanent debility, and sometimes sudden death. Plaques that have ruptured are called complicated lesions. The extracellular matrix of
28724-588: The variation in sex ratios of coronary heart disease mortality. Another study reports similar results finding that sex differences explains nearly half the risk associated with cardiovascular diseases One of the proposed explanations for sex differences in cardiovascular diseases is hormonal difference. Among women, estrogen is the predominant sex hormone. Estrogen may have protective effects on glucose metabolism and hemostatic system, and may have direct effect in improving endothelial cell function. The production of estrogen decreases after menopause, and this may change
28896-531: The vascular bed lining, the endothelium , then by their migration to the sub-endothelial space, and further activation into monocyte-derived macrophages . The primary documented driver of this process is oxidized lipoprotein particles within the wall, beneath the endothelial cells, though upper normal or elevated concentrations of blood glucose also plays a major role and not all factors are fully understood. Fatty streaks may appear and disappear. Low-density lipoprotein (LDL) particles in blood plasma invade
29068-414: The ventricles are contracting, the atria are relaxed and collecting blood. When the ventricles are relaxed in diastole, the atria contract to pump blood to the ventricles. This coordination ensures blood is pumped efficiently to the body. At the beginning of the cardiac cycle, the ventricles are relaxing. As they do so, they are filled by blood passing through the open mitral and tricuspid valves. After
29240-401: The ventricles have completed most of their filling, the atria contract, forcing further blood into the ventricles and priming the pump. Next, the ventricles start to contract. As the pressure rises within the cavities of the ventricles, the mitral and tricuspid valves are forced shut. As the pressure within the ventricles rises further, exceeding the pressure with the aorta and pulmonary arteries,
29412-402: The women's smaller body size and arterial dimensions which are independent of menopause. Cigarettes are the major form of smoked tobacco. Risks to health from tobacco use result not only from direct consumption of tobacco, but also from exposure to second-hand smoke. Approximately 10% of cardiovascular disease is attributed to smoking; however, people who quit smoking by age 30 have almost as low
29584-458: Was also found between heart disease and exposure to compounds which are no longer permitted in certain work environments, such as phenoxy acids containing TCDD (dioxin) or asbestos . Workplace exposure to silica dust or asbestos is also associated with pulmonary heart disease . There is evidence that workplace exposure to lead, carbon disulphide, phenoxyacids containing TCDD, as well as working in an environment where aluminum
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