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71-460: In adults, the QRS complex normally lasts 80 to 100 ms ; in children it may be shorter. The Q, R, and S waves occur in rapid succession, do not all appear in all leads, and reflect a single event and thus are usually considered together. A Q wave is any downward deflection immediately following the P wave . An R wave follows as an upward deflection, and the S wave is any downward deflection after

142-411: A blood test for biomarkers (the cardiac protein troponin ). When there is evidence of an MI, it may be classified as an ST elevation myocardial infarction (STEMI) or Non-ST elevation myocardial infarction (NSTEMI) based on the results of an ECG . The phrase "heart attack" is often used non-specifically to refer to myocardial infarction. An MI is different from—but can cause— cardiac arrest , where

213-658: A cold sweat , feeling tired , and decreased level of consciousness . About 30% of people have atypical symptoms. Women more often present without chest pain and instead have neck pain, arm pain or feel tired. Among those over 75 years old, about 5% have had an MI with little or no history of symptoms. An MI may cause heart failure , an irregular heartbeat , cardiogenic shock or cardiac arrest . Most MIs occur due to coronary artery disease . Risk factors include high blood pressure , smoking , diabetes , lack of exercise , obesity , high blood cholesterol , poor diet, and excessive alcohol intake . The complete blockage of

284-475: A coronary artery caused by a rupture of an atherosclerotic plaque is usually the underlying mechanism of an MI. MIs are less commonly caused by coronary artery spasms , which may be due to cocaine , significant emotional stress (often known as Takotsubo syndrome or broken heart syndrome ) and extreme cold, among others. Many tests are helpful to help with diagnosis, including electrocardiograms (ECGs), blood tests and coronary angiography . An ECG, which

355-486: A heart attack , occurs when blood flow decreases or stops in one of the coronary arteries of the heart , causing infarction (tissue death) to the heart muscle . The most common symptom is retrosternal chest pain or discomfort that classically radiates to the left shoulder, arm, or jaw. The pain may occasionally feel like heartburn . This is the dangerous type of Acute coronary syndrome . Other symptoms may include shortness of breath , nausea , feeling faint ,

426-417: A QRS complex. However, correct interpretation of difficult ECGs requires exact labeling of the various waves. Some authors use lowercase and capital letters, depending on the relative size of each wave. For example, an Rs complex would be positively deflected, while an rS complex would be negatively deflected. If both complexes were labeled RS, it would be impossible to appreciate this distinction without viewing

497-474: A benefit of 15 to 45%. Physical activity can reduce the risk of cardiovascular disease, and people at risk are advised to engage in 150 minutes of moderate or 75 minutes of vigorous intensity aerobic exercise a week. Keeping a healthy weight, drinking alcohol within the recommended limits, and quitting smoking reduce the risk of cardiovascular disease. Substituting unsaturated fats such as olive oil and rapeseed oil instead of saturated fats may reduce

568-428: A common, and sometimes the only symptom, occurring when damage to the heart limits the output of the left ventricle , with breathlessness arising either from low oxygen in the blood or pulmonary edema . Other less common symptoms include weakness, light-headedness , palpitations , and abnormalities in heart rate or blood pressure . These symptoms are likely induced by a massive surge of catecholamines from

639-480: A late consequence of Kawasaki disease . Calcium deposits in the coronary arteries can be detected with CT scans . Calcium seen in coronary arteries can provide predictive information beyond that of classical risk factors. High blood levels of the amino acid homocysteine is associated with premature atherosclerosis; whether elevated homocysteine in the normal range is causal is controversial. In people without evident coronary artery disease , possible causes for

710-431: A myocardial infarction before age 55 years, or a female first-degree relative (mother, sister) less than age 65 increases a person's risk of MI. Genome-wide association studies have found 27 genetic variants that are associated with an increased risk of myocardial infarction. The strongest association of MI has been found with chromosome 9 on the short arm p at locus 21, which contains genes CDKN2A and 2B, although

781-463: A myocardial infarction increases with older age, low physical activity, and low socioeconomic status . Heart attacks appear to occur more commonly in the morning hours, especially between 6AM and noon. Evidence suggests that heart attacks are at least three times more likely to occur in the morning than in the late evening. Shift work is also associated with a higher risk of MI. One analysis has found an increase in heart attacks immediately following

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852-406: A myocardial infarction. Spasm of coronary arteries, such as Prinzmetal's angina may cause blockage. If impaired blood flow to the heart lasts long enough, it triggers a process called the ischemic cascade ; the heart cells in the territory of the blocked coronary artery die ( infarction ), chiefly through necrosis , and do not grow back. A collagen scar forms in their place. When an artery

923-543: A myocardial infarction. The flow of blood can be imaged, and contrast dyes may be given to improve image. Other scans using radioactive contrast include SPECT CT-scans using thallium , sestamibi ( MIBI scans ) or tetrofosmin ; or a PET scan using Fludeoxyglucose or rubidium-82 . These nuclear medicine scans can visualize the perfusion of heart muscle. SPECT may also be used to determine viability of tissue, and whether areas of ischemia are inducible. Medical societies and professional guidelines recommend that

994-637: A person localizes the chest pain by clenching one or both fists over their sternum , has classically been thought to be predictive of cardiac chest pain, although a prospective observational study showed it had a poor positive predictive value . Typically, chest pain because of ischemia, be it unstable angina or myocardial infarction, lessens with the use of nitroglycerin , but nitroglycerin may also relieve chest pain arising from non-cardiac causes. Chest pain may be accompanied by sweating , nausea or vomiting, and fainting , and these symptoms may also occur without any pain at all. Dizziness or lightheadedness

1065-407: A previous heart attack is also suggestive. The pain associated with MI is usually diffuse, does not change with position, and lasts for more than 20 minutes. It might be described as pressure, tightness, knifelike, tearing, burning sensation (all these are also manifested during other diseases). It could be felt as an unexplained anxiety, and pain might be absent altogether. Levine's sign , in which

1136-560: A rise in biomarkers, a rise in the ST segment , changes in the shape or flipping of T waves , new Q waves , or a new left bundle branch block can be used to diagnose an AMI. In addition, ST elevation can be used to diagnose an ST segment myocardial infarction (STEMI). A rise must be new in V2 and V3 ≥2 mm (0,2 mV) for males or ≥1.5 mm (0.15 mV) for females or ≥1 mm (0.1 mV) in two other adjacent chest or limb leads . ST elevation

1207-409: A series of leads placed on a person's chest that measure electrical activity associated with contraction of the heart muscle. The taking of an ECG is an important part of the workup of an AMI, and ECGs are often not just taken once but may be repeated over minutes to hours, or in response to changes in signs or symptoms. ECG readouts produce a waveform with different labeled features. In addition to

1278-564: A sharp angle with the last part of the QRS complex. However, when the ST segment is sloped or the QRS complex is wide, the two features do not form a sharp angle and the location of the J-point is less clear. There is no consensus on the precise location of the J-point in these circumstances. Two possible definitions are: Not every QRS complex contains a Q wave, an R wave, and an S wave. By convention, any combination of these waves can be referred to as

1349-406: A significant effect on blood cholesterol and thus recommendations about its consumption may not be needed. Trans fats do appear to increase risk. Acute and prolonged intake of high quantities of alcoholic drinks (3–4 or more daily) increases the risk of a heart attack. Family history of ischemic heart disease or MI, particularly if one has a male first-degree relative (father, brother) who had

1420-601: Is a known risk factor, particularly high low-density lipoprotein , low high-density lipoprotein , and high triglycerides . Many risk factors for myocardial infarction are potentially modifiable, with the most important being tobacco smoking (including secondhand smoke ). Smoking appears to be the cause of about 36% and obesity the cause of 20% of coronary artery disease . Lack of physical activity has been linked to 7–12% of cases. Less common causes include stress-related causes such as job stress , which accounts for about 3% of cases, and chronic high stress levels. There

1491-454: Is a recording of the heart's electrical activity, may confirm an ST elevation MI ( STEMI ), if ST elevation is present. Commonly used blood tests include troponin and less often creatine kinase MB . Treatment of an MI is time-critical. Aspirin is an appropriate immediate treatment for a suspected MI. Nitroglycerin or opioids may be used to help with chest pain; however, they do not improve overall outcomes. Supplemental oxygen

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1562-858: Is a unit of time in the International System of Units equal to one thousandth (0.001 or 10 or / 1000 ) of a second or 1000 microseconds . A millisecond is to one second, as one second is to approximately 16.67 minutes. A unit of 10 milliseconds may be called a centisecond , and one of 100 milliseconds a decisecond , but these names are rarely used. To help compare orders of magnitude of different times , this page lists times between 10 seconds and 10 seconds (1 milli second and one second). See also times of other orders of magnitude . The Apollo Guidance Computer used metric units internally, with centiseconds used for time calculation and measurement. Myocardial infarction A myocardial infarction ( MI ), commonly known as

1633-806: Is also an important modifiable risk. Short-term exposure to air pollution such as carbon monoxide , nitrogen dioxide , and sulfur dioxide (but not ozone ) has been associated with MI and other acute cardiovascular events. For sudden cardiac deaths, every increment of 30 units in Pollutant Standards Index correlated with an 8% increased risk of out-of-hospital cardiac arrest on the day of exposure. Extremes of temperature are also associated. A number of acute and chronic infections including Chlamydophila pneumoniae , influenza , Helicobacter pylori , and Porphyromonas gingivalis among others have been linked to atherosclerosis and myocardial infarction. Myocardial infarction can also occur as

1704-499: Is associated with infarction, and may be preceded by changes indicating ischemia, such as ST depression or inversion of the T waves. Abnormalities can help differentiate the location of an infarct, based on the leads that are affected by changes. Early STEMIs may be preceded by peaked T waves. Other ECG abnormalities relating to complications of acute myocardial infarctions may also be evident, such as atrial or ventricular fibrillation . Noninvasive imaging plays an important role in

1775-517: Is blocked, cells lack oxygen , needed to produce ATP in mitochondria . ATP is required for the maintenance of electrolyte balance, particularly through the Na/K ATPase . This leads to an ischemic cascade of intracellular changes, necrosis and apoptosis of affected cells. Cells in the area with the worst blood supply, just below the inner surface of the heart ( endocardium ), are most susceptible to damage. Ischemia first affects this region,

1846-433: Is common and occurs due to reduction in oxygen and blood to the brain. In females, the most common symptoms of myocardial infarction include shortness of breath, weakness, and fatigue . Females are more likely to have unusual or unexplained tiredness and nausea or vomiting as symptoms. Females having heart attacks are more likely to have palpitations, back pain, labored breath, vomiting, and left arm pain than males, although

1917-415: Is commonly attributed to anterior myocardial infarction , but it may also be caused by left bundle branch block , Wolff–Parkinson–White syndrome , right and left ventricular hypertrophy , or a faulty ECG recording technique. R wave peak time (RWPT) represents the time from the onset of QRS complex to the peak of R wave, which is usually measured in aVL and V5 or V6 leads. R-peak time for right ventricle

1988-522: Is essential in signal processing equipment for heart rate measurement and it is the main feature used for arrhythmia detection. The definition of poor R wave progression (PRWP) varies in the literature. It may be defined, for example, as R wave of less than 2–4 mm in leads V 3 or V 4 and/or presence of a reversed R wave progression, which is defined as R in V 4 < R in V 3 or R in V 3 < R in V 2 or R in V 2 < R in V 1 , or any combination of these. Poor R wave progression

2059-399: Is measured from leads V1 or V2, where upper range of normal is 35 ms. R wave peak time for left ventricle is measured from lead V5 or V6 and 45 ms is the upper range of normal. R wave peak time is considered to be prolonged if it's more than 45 ms. The point where the QRS complex meets the ST segment is the J-point. The J-point is easy to identify when the ST segment is horizontal and forms

2130-477: Is not the only cause of myocardial infarction, but it may exacerbate or contribute to other causes. A myocardial infarction may result from a heart with a limited blood supply subject to increased oxygen demands, such as in fever, a fast heart rate , hyperthyroidism , too few red blood cells in the bloodstream , or low blood pressure . Damage or failure of procedures such as percutaneous coronary intervention (PCI) or coronary artery bypass grafts (CABG) may cause

2201-430: Is one of the most common symptoms of acute myocardial infarction and is often described as a sensation of tightness, pressure, or squeezing. Pain radiates most often to the left arm, but may also radiate to the lower jaw, neck, right arm, back, and upper abdomen . The pain most suggestive of an acute MI, with the highest likelihood ratio , is pain radiating to the right arm and shoulder. Similarly, chest pain similar to

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2272-414: Is recommended in those with low oxygen levels or shortness of breath. In a STEMI, treatments attempt to restore blood flow to the heart and include percutaneous coronary intervention (PCI), where the arteries are pushed open and may be stented , or thrombolysis , where the blockage is removed using medications. People who have a non-ST elevation myocardial infarction ( NSTEMI ) are often managed with

2343-412: Is still unable to be distributed to the affected myocardium despite clearing the occlusion—also contributes to myocardial injury. Topical endothelial swelling is one of many factors contributing to this phenomenon. A myocardial infarction, according to current consensus, is defined by elevated cardiac biomarkers with a rising or falling trend and at least one of the following: A myocardial infarction

2414-457: Is usually clinically classified as an ST-elevation MI (STEMI) or a non-ST elevation MI (NSTEMI). These are based on ST elevation , a portion of a heartbeat graphically recorded on an ECG . STEMIs make up about 25–40% of myocardial infarctions. A more explicit classification system, based on international consensus in 2012, also exists. This classifies myocardial infarctions into five types: There are many different biomarkers used to determine

2485-445: Is varying evidence about the importance of saturated fat in the development of myocardial infarctions. Eating polyunsaturated fat instead of saturated fats has been shown in studies to be associated with a decreased risk of myocardial infarction, while other studies find little evidence that reducing dietary saturated fat or increasing polyunsaturated fat intake affects heart attack risk. Dietary cholesterol does not appear to have

2556-428: Is where the QRS complex changes from predominantly negative to predominantly positive (R/S ratio becoming >1), and this usually occurs at V 3 or V 4 . It is normal to have the transition zone at V 2 (called "early transition") and at V 5 (called "delayed transition"). In biomedical engineering, the maximum amplitude in the R wave is usually called "R peak amplitude", or just "R peak". Accurate R peak detection

2627-492: The bundle of His and Purkinje fibers . If they are working efficiently, the QRS complex duration in adults is 80 to 110 ms . Any abnormality of conduction takes longer and causes "widened" QRS complexes. In bundle branch block , there can be an abnormal second upward deflection within the QRS complex. In this case, such a second upward deflection is referred to as R′ (pronounced "R prime "). This would be described as an RSR′ pattern. Ventricles contain more muscle mass than

2698-661: The elderly , in those with diabetes mellitus and after heart transplantation . In people with diabetes, differences in pain threshold , autonomic neuropathy , and psychological factors have been cited as possible explanations for the lack of symptoms. In heart transplantation, the donor heart is not fully innervated by the nervous system of the recipient. The most prominent risk factors for myocardial infarction are older age, actively smoking , high blood pressure , diabetes mellitus , and total cholesterol and high-density lipoprotein levels. Many risk factors of myocardial infarction are shared with coronary artery disease ,

2769-480: The health impact assessment of regional and local plans and policies. Most guidelines recommend combining different preventive strategies. A 2015 Cochrane Review found some evidence that such an approach might help with  blood pressure ,  body mass index  and  waist circumference . However, there was insufficient evidence to show an effect on mortality or actual cardio-vascular events. Statins , drugs that act to lower blood cholesterol, decrease

2840-522: The single nucleotide polymorphisms that are implicated are within a non-coding region. The majority of these variants are in regions that have not been previously implicated in coronary artery disease. The following genes have an association with MI: PCSK9 , SORT1 , MIA3 , WDR12 , MRAS , PHACTR1 , LPA , TCF21 , MTHFDSL , ZC3HC1 , CDKN2A , 2B , ABO , PDGF0 , APOA5 , MNF1ASM283 , COL4A1 , HHIPC1 , SMAD3 , ADAMTS7 , RAS1 , SMG6 , SNF8 , LDLR , SLC5A3 , MRPS6 , KCNE2 . The risk of having

2911-481: The subendocardial region, and tissue begins to die within 15–30 minutes of loss of blood supply. The dead tissue is surrounded by a zone of potentially reversible ischemia that progresses to become a full-thickness transmural infarct. The initial "wave" of infarction can take place over 3–4 hours. These changes are seen on gross pathology and cannot be predicted by the presence or absence of Q waves on an ECG. The position, size and extent of an infarct depends on

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2982-551: The sympathetic nervous system , which occurs in response to pain and, where present, low blood pressure . Loss of consciousness can occur in myocardial infarctions due to inadequate blood flow to the brain and cardiogenic shock , and sudden death , frequently due to the development of ventricular fibrillation . When the brain was without oxygen for too long due to a myocardial infarction, coma and persistent vegetative state can occur. Cardiac arrest, and atypical symptoms such as palpitations , occur more frequently in females,

3053-440: The QRS complex may be useful for detection of coronary artery disease during an exercise stress test . Duration longer than 45 ms might indicate left posterior fascicular block , LVH or LBBB . Normal Q waves, when present, represent depolarization of the interventricular septum . For this reason, they are referred to as septal Q waves and can be appreciated in the lateral leads I, aVL, V5 and V6. Pathologic Q waves occur when

3124-523: The R wave. The T wave follows the S wave, and in some cases, an additional U wave follows the T wave. To measure the QRS interval start at the end of the PR interval (or beginning of the Q wave) to the end of the S wave. Normally this interval is 0.08 to 0.10 seconds. When the duration is longer it is considered a wide QRS complex. Depolarization of the heart ventricles occurs almost simultaneously, via

3195-537: The United States. In the developed world, the risk of death in those who have had a STEMI is about 10%. Rates of MI for a given age have decreased globally between 1990 and 2010. In 2011, an MI was one of the top five most expensive conditions during inpatient hospitalizations in the US, with a cost of about $ 11.5 billion for 612,000 hospital stays. Myocardial infarction (MI) refers to tissue death ( infarction ) of

3266-801: The actual ECG. Monomorphic refers to all QRS waves in a single lead being similar in shape. Polymorphic means that the QRS change from complex to complex. These terms are used in the description of ventricular tachycardia . A common algorithm used for QRS complex detection is the Pan-Tompkins algorithm (or method); another is based on the Hilbert transform . Numerous other algorithms have been proposed and investigated. In recent research, heart beat detection methods based on visibility graphs have been introduced, enabling fast and sample-precise R-peak annotation even in noisy ECG. Millisecond A millisecond (from milli- and second ; symbol: ms )

3337-432: The acute diagnostic algorithm; however, it can confirm a clinical suspicion of Chronic Coronary Syndrome when the patient's history, physical examination (including cardiac examination ) ECG, and cardiac biomarkers suggest coronary artery disease. Echocardiography , an ultrasound scan of the heart, is able to visualize the heart, its size, shape, and any abnormal motion of the heart walls as they beat that may indicate

3408-409: The affected artery, totality of the blockage, duration of the blockage, the presence of collateral blood vessels , oxygen demand, and success of interventional procedures. Tissue death and myocardial scarring alter the normal conduction pathways of the heart and weaken affected areas. The size and location put a person at risk of abnormal heart rhythms (arrhythmias) or heart block , aneurysm of

3479-497: The atria. Therefore, the QRS complex is considerably larger than the P wave. The QRS complex is often used to determine the axis of the electrocardiogram, although it is also possible to determine a separate P wave axis. The duration, amplitude, and morphology of the QRS complex are useful in diagnosing cardiac arrhythmias , conduction abnormalities , ventricular hypertrophy , myocardial infarction , electrolyte derangements , and other disease states. High frequency analysis of

3550-647: The blood thinner heparin , with the additional use of PCI in those at high risk. In people with blockages of multiple coronary arteries and diabetes, coronary artery bypass surgery (CABG) may be recommended rather than angioplasty . After an MI, lifestyle modifications, along with long-term treatment with aspirin, beta blockers and statins , are typically recommended. Worldwide, about 15.9 million myocardial infarctions occurred in 2015. More than 3 million people had an ST elevation MI, and more than 4 million had an NSTEMI. STEMIs occur about twice as often in men as women. About one million people have an MI each year in

3621-405: The diagnosis and characterisation of myocardial infarction. Tests such as chest X-rays can be used to explore and exclude alternate causes of a person's symptoms. Echocardiography may assist in modifying clinical suspicion of ongoing myocardial infarction in patients that can't be ruled out or ruled in following initial ECG and Troponin testing. Myocardial perfusion imaging has no role in

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3692-616: The diagnostic accuracy of troponin testing is improving over time. One high-sensitivity cardiac troponin can rule out a heart attack as long as the ECG is normal. Other tests, such as CK-MB or myoglobin , are discouraged. CK-MB is not as specific as troponins for acute myocardial injury, and may be elevated with past cardiac surgery, inflammation or electrical cardioversion; it rises within 4–8 hours and returns to normal within 2–3 days. Copeptin may be useful to rule out MI rapidly when used along with troponin. Electrocardiograms (ECGs) are

3763-414: The elderly, those with diabetes, in people who have just had surgery, and in critically ill patients. "Silent" myocardial infarctions can happen without any symptoms at all. These cases can be discovered later on electrocardiograms , using blood enzyme tests, or at autopsy after a person has died. Such silent myocardial infarctions represent between 22 and 64% of all infarctions, and are more common in

3834-456: The electrical signal passes through stunned or scarred heart muscle ; as such, they are usually markers of previous myocardial infarctions , with subsequent fibrosis. A pathologic Q wave is defined as having a deflection amplitude of 25% or more of the subsequent R wave, or being > 0.04 s (40 ms) in width and > 2 mm in amplitude. However, diagnosis requires the presence of this pattern in more than one corresponding lead. Looking at

3905-637: The greatest support is the Mediterranean diet . Vitamins and mineral supplements are of no proven benefit, and neither are plant stanols or sterols . Public health measures may also act at a population level to reduce the risk of myocardial infarction, for example by reducing unhealthy diets (excessive salt, saturated fat, and trans-fat) including food labeling and marketing requirements as well as requirements for catering and restaurants and stimulating physical activity. This may be part of regional cardiovascular disease prevention programs or through

3976-465: The heart is not contracting at all or so poorly that all vital organs cease to function, thus leading to death. It is also distinct from heart failure , in which the pumping action of the heart is impaired. However, an MI may lead to heart failure. Chest pain that may or may not radiate to other parts of the body is the most typical and significant symptom of myocardial infarction. It might be accompanied by other symptoms such as sweating. Chest pain

4047-410: The heart muscle ( myocardium ) caused by ischemia , the lack of oxygen delivery to myocardial tissue. It is a type of acute coronary syndrome , which describes a sudden or short-term change in symptoms related to blood flow to the heart. Unlike the other type of acute coronary syndrome, unstable angina , a myocardial infarction occurs when there is cell death , which can be estimated by measuring by

4118-441: The heart ventricles , inflammation of the heart wall following infarction, and rupture of the heart wall that can have catastrophic consequences. Injury to the myocardium also occurs during re-perfusion. This might manifest as ventricular arrhythmia. The re-perfusion injury is a consequence of the calcium and sodium uptake from the cardiac cells and the release of oxygen radicals during reperfusion. No-reflow phenomenon—when blood

4189-729: The heart, lungs , gastrointestinal tract , aorta , and other muscles, bones and nerves surrounding the chest. In addition to myocardial infarction, other causes include angina , insufficient blood supply ( ischemia ) to the heart muscles without evidence of cell death, gastroesophageal reflux disease ; pulmonary embolism , tumors of the lungs, pneumonia , rib fracture , costochondritis , heart failure and other musculoskeletal injuries. Rarer severe differential diagnoses include aortic dissection , esophageal rupture , tension pneumothorax , and pericardial effusion causing cardiac tamponade . The chest pain in an MI may mimic heartburn . Causes of sudden-onset breathlessness generally involve

4260-402: The incidence and mortality rates of myocardial infarctions. They are often recommended in those at an elevated risk of cardiovascular diseases. Aspirin has been studied extensively in people considered at increased risk of myocardial infarction. Based on numerous studies in different groups (e.g. people with or without diabetes), there does not appear to be a benefit strong enough to outweigh

4331-666: The lungs or heart – including pulmonary edema , pneumonia, allergic reactions and asthma , and pulmonary embolus, acute respiratory distress syndrome and metabolic acidosis . There are many different causes of fatigue, and myocardial infarction is not a common cause. There is a large crossover between the lifestyle and activity recommendations to prevent a myocardial infarction, and those that may be adopted as secondary prevention after an initial myocardial infarction, because of shared risk factors and an aim to reduce atherosclerosis affecting heart vessels. The influenza vaccine also appear to protect against myocardial infarction with

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4402-610: The myocardial infarction are coronary spasm or coronary artery dissection . The most common cause of a myocardial infarction is the rupture of an atherosclerotic plaque on an artery supplying heart muscle. Plaques can become unstable, rupture, and additionally promote the formation of a blood clot that blocks the artery; this can occur in minutes. Blockage of an artery can lead to tissue death in tissue being supplied by that artery. Atherosclerotic plaques are often present for decades before they result in symptoms. The gradual buildup of cholesterol and fibrous tissue in plaques in

4473-419: The physician confirm a person is at high risk for Chronic Coronary Syndrome before conducting diagnostic non-invasive imaging tests to make a diagnosis, as such tests are unlikely to change management and result in increased costs. Patients who have a normal ECG and who are able to exercise, for example, most likely do not merit routine imaging. There are many causes of chest pain , which can originate from

4544-471: The plaque and act to stabilize it. A stable plaque may have a thick fibrous cap with calcification . If there is ongoing inflammation, the cap may be thin or ulcerate. Exposed to the pressure associated with blood flow, plaques, especially those with a thin lining, may rupture and trigger the formation of a blood clot (thrombus). The cholesterol crystals have been associated with plaque rupture through mechanical injury and inflammation. Atherosclerotic disease

4615-506: The precordial leads, the R wave usually progresses from showing an rS-type complex in V 1 with an increasing R and a decreasing S wave when moving toward the left side. There is usually a qR-type of complex in V 5 and V 6, with the R-wave amplitude usually taller in V 5 than in V 6 . It is normal to have a narrow QS and rSr' patterns in V 1 , and this is also the case for qRs and R patterns in V 5 and V 6 . The transition zone

4686-487: The presence of cardiac muscle damage. Troponins , measured through a blood test, are considered to be the best, and are preferred because they have greater sensitivity and specificity for measuring injury to the heart muscle than other tests. A rise in troponin occurs within 2–3 hours of injury to the heart muscle, and peaks within 1–2 days. The level of the troponin, as well as a change over time, are useful in measuring and diagnosing or excluding myocardial infarctions, and

4757-512: The primary cause of myocardial infarction, with other risk factors including male sex, low levels of physical activity, a past family history , obesity , and alcohol use . Risk factors for myocardial disease are often included in risk factor stratification scores, such as the Framingham Risk Score . At any given age, men are more at risk than women for the development of cardiovascular disease. High levels of blood cholesterol

4828-486: The risk of myocardial infarction, although there is not universal agreement. Dietary modifications are recommended by some national authorities, with recommendations including increasing the intake of wholegrain starch, reducing sugar intake (particularly of refined sugar), consuming five portions of fruit and vegetables daily, consuming two or more portions of fish per week, and consuming 4–5 portions of unsalted nuts , seeds , or legumes per week. The dietary pattern with

4899-399: The start of daylight saving time . Women who use combined oral contraceptive pills have a modestly increased risk of myocardial infarction, especially in the presence of other risk factors. The use of non-steroidal anti inflammatory drugs (NSAIDs), even for as short as a week, increases risk. Endometriosis in women under the age of 40 is an identified risk factor. Air pollution

4970-400: The studies showing these differences had high variability. Females are less likely to report chest pain during a heart attack and more likely to report nausea, jaw pain, neck pain, cough, and fatigue, although these findings are inconsistent across studies. Females with heart attacks also had more indigestion, dizziness , loss of appetite , and loss of consciousness. Shortness of breath is

5041-529: The wall of the coronary arteries or other arteries, typically over decades, is termed atherosclerosis . Atherosclerosis is characterized by progressive inflammation of the walls of the arteries. Inflammatory cells, particularly macrophages , move into affected arterial walls. Over time, they become laden with cholesterol products, particularly LDL , and become foam cells . A cholesterol core forms as foam cells die. In response to growth factors secreted by macrophages, smooth muscle and other cells move into

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