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89-420: A heart is a muscular organ that pumps blood in various species. Heart may also refer to: 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 the circulatory system . The pumped blood carries oxygen and nutrients to the tissue, while carrying metabolic waste such as carbon dioxide to

178-402: A heart attack (31%), pulmonary embolism (2%), pneumothorax , pericarditis (4%), aortic dissection (1%) and esophageal rupture . Other common causes include gastroesophageal reflux disease (30%), muscle or skeletal pain (28%), pneumonia (2%), shingles (0.5%), pleuritis , traumatic and anxiety disorders . Determining the cause of chest pain is based on a person's medical history,

267-476: A physical exam and other medical tests. About 3% of heart attacks , however, are initially missed. Management of chest pain is based on the underlying cause. Initial treatment often includes the medications aspirin and nitroglycerin . The response to treatment does not usually indicate whether the pain is heart-related. When the cause is unclear, the person may be referred for further evaluation. Chest pain represents about 5% of presenting problems to

356-440: 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

445-456: 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

534-558: A higher likelihood of being related to acute coronary syndrome , or inadequate supply of blood to the heart muscle, but even without these symptoms chest pain may be a sign of acute coronary syndrome . Other clues in the history can help lower the suspicion for myocardial infarction. These include chest pain described as "sharp" or "stabbing", chest pain that is positional or pleuritic in nature, and chest pain that can be reproduced with palpation. However, both atypical and typical symptoms of acute coronary syndrome can occur, and in general

623-533: A history cannot be enough to rule out the diagnosis of acute coronary syndrome. In some cases, chest pain may not even be a symptom of an acute cardiac event. An estimated 33% of persons with myocardial infarction in the United States do not present with chest pain, and carry a significantly higher mortality as a result of delayed treatment. Careful medical history and physical examination is essential in separating dangerous from trivial causes of disease, and

712-438: 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

801-400: 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

890-470: 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

979-408: A person's vital signs , airway and breathing , and level of consciousness . This may also include attachment of ECG leads , cardiac monitors , intravenous lines and other medical devices depending on initial evaluation. After evaluation of a person's history, risk factors, physical examination, laboratory testing and imaging, management begins depending on suspected diagnoses. Depending upon

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1068-789: A person's risk factors can be extremely useful in ruling in or ruling out serious causes of chest pain. For example, heart attack and thoracic aortic dissection are very rare in healthy individuals under 30 years of age, but significantly more common in individuals with significant risk factors, such as older age, smoking, hypertension , diabetes , history of coronary artery disease or stroke , positive family history (premature atherosclerosis , cholesterol disorders, heart attack at early age), and other risk factors. Chest pain that radiates to one or both shoulders or arms, chest pain that occurs with physical activity, chest pain associated with nausea or vomiting, chest pain accompanied by diaphoresis or sweating, or chest pain described as "pressure," has

1157-425: 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

1246-402: 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

1335-460: 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

1424-406: A recommendation for increased exercise are often used as treatment. Studies have shown conflicting results on the efficacy of these treatments. A combination therapy of nonsteroidal anti-inflammatory drugs and manipulation therapy with at-home exercises has been shown to be most effective in treatment of musculoskeletal chest pain. Chest pain is a common presenting problem . Overall chest pain

1513-480: 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

1602-400: 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

1691-404: 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

1780-428: 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 )

1869-480: 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

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1958-451: 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

2047-488: Is reasonable for EMS dispatchers to recommend it in people with no recent serious bleeding. Supplemental oxygen was used in the past for most people with chest pain but is not needed unless the oxygen saturations are less than 94% or there are signs of respiratory distress . Entonox is frequently used by EMS personnel in the prehospital environment. However, there is little evidence about its effectiveness. Hospital care of chest pain begins with initial survey of

2136-553: Is reproducible during the physical exam with contact of the chest wall is more indicative of non-cardiac chest pain, but still cannot completely rule out acute coronary syndrome. For this reason, in general, additional tests are required to establish the diagnosis. In the emergency department the typical approach to chest pain involves ruling out the most dangerous causes: heart attack , pulmonary embolism , thoracic aortic dissection , esophageal rupture , tension pneumothorax , and cardiac tamponade . By elimination or confirmation of

2225-573: Is responsible for an estimated 6% of all emergency department visits in the United States and is the most common reason for hospital admission. Chest pain is also very common in primary care clinics , representing 1-3% of all visits. The rate of emergency department visits in the US for chest pain decreased 10% from 1999 to 2008. but a subsequent increase of 13% was seen from 2006 to 2011. Less than 20% of all cases of chest pain admissions are found to be due to coronary artery disease. The rate of chest pain as

2314-612: 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

2403-404: 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

2492-505: 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

2581-402: 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

2670-484: 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

2759-451: The emergency room . In the United States, about 8 million people go to the emergency department with chest pain a year. Of these, about 60% are admitted to either the hospital or an observation unit. The cost of emergency visits for chest pain in the United States is more than US$ 8 billion per year. Chest pain accounts for about 0.5% of visits by children to the emergency department. Chest pain may present in different ways depending upon

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2848-405: 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,

2937-400: 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, the right atrium and ventricle are referred together as

3026-402: 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

3115-418: 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

3204-430: 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

3293-404: 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

3382-411: 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

3471-403: 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 a small amount of fluid . The wall of

3560-463: 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

3649-405: 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

Heart (disambiguation) - Misplaced Pages Continue

3738-458: 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,

3827-400: 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),

3916-400: 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

4005-402: 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

4094-409: 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,

4183-403: 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

4272-434: 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

4361-455: 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

4450-443: 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

4539-415: 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

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4628-566: 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. Chest pain Serious and relatively common causes include acute coronary syndrome such as

4717-436: 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

4806-562: The diagnosis, a person may be placed in the intensive care unit , admitted to the hospital, or be treated outpatient . For persons with suspected cardiac chest pain or acute coronary syndrome , or other emergent diagnoses such as pneumothorax , pulmonary embolism , or aortic dissection , admission to the hospital is most often recommended for further treatment. For people with non-cardiac chest pain, cognitive behavioral therapy might be helpful on an outpatient basis. A 2015 Cochrane review found that cognitive behavioral therapy might reduce

4895-403: 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

4984-438: 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

5073-417: 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

5162-481: 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

5251-517: The frequency of chest pain episodes the first three months after treatment. For persons with chest pain due to gastroesophageal reflux disease , a proton-pump inhibitor has been shown to be the most effective treatment. However, treatment with proton pump inhibitors has been shown to be no better than placebo in persons with noncardiac chest pain not caused by gastroesophageal reflux disease. For musculoskeletal causes of chest pain, manipulation therapy or chiropractic therapy , acupuncture , or

5340-593: 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

5429-406: 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

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5518-433: 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 the sinoatrial node . These generate an electric current that causes

5607-414: 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

5696-413: 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

5785-427: 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

5874-414: 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

5963-473: 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

6052-673: The management of chest pain may be done on specialized units (termed medical assessment units ) to concentrate the investigations. Occasionally, invisible medical signs will direct the diagnosis towards particular causes, such as Levine's sign in cardiac ischemia . However, in the case of acute coronary syndrome , a third heart sound , diaphoresis , and hypotension are the most strongly associated physical exam findings. However these signs are limited in their prognostic and diagnostic value. Other physical exam findings suggestive of cardiac chest pain may include hypertension , tachycardia , bradycardia , and new heart murmurs . Chest pain that

6141-413: 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

6230-419: 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

6319-621: The most common causes of chest pain include: gastrointestinal (42%), coronary artery disease (31%), musculoskeletal (28%), pericarditis (4%) and pulmonary embolism (2%). Other less common causes include: pneumonia, lung cancer, and aortic aneurysms. Psychogenic causes of chest pain can include panic attacks ; however, this is a diagnosis of exclusion. In children, the most common causes for chest pain are musculoskeletal (76–89%), exercise-induced asthma (4–12%), gastrointestinal illness (8%), and psychogenic causes (4%). Chest pain in children can also have congenital causes. Knowing

6408-727: The most serious causes, a diagnosis of the origin of the pain may be made. Often, no definite cause will be found and reassurance is then provided. The Global Registry of Acute Coronary Events score and the Thrombosis in Myocardial Infarction performed at time of admission may help stratify persons into low, intermediate and high risk groups for acute coronary syndrome. However these scores do not provide management guidelines for risk-stratified persons. The HEART score, stratifies persons into low-risk and high-risk groups, and recommends either discharge or admission based upon

6497-419: 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

6586-400: 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

6675-414: 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

6764-515: 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

6853-587: 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

6942-422: 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

7031-427: 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

7120-424: 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

7209-414: 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

7298-486: The score. Cumulative score: If acute coronary syndrome ("heart attack") is suspected, many people are admitted briefly for observation, sequential ECGs, and measurement of cardiac enzymes in the blood over time. On occasion, further tests on follow up may determine the cause. Depending on the differential diagnoses made based on history and physical examination, a number of tests may be ordered: Blood tests: Other tests: Management of chest pain varies with

7387-471: 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

7476-511: 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

7565-408: 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

7654-451: The underlying cause of the pain and the stage of care. If a chest pain patient suspects that he is suffering a myocardial infarction, he can calm down, remain in a position that is comfortable, calling emergency medical services and trying any other action of the applicable first aid process. Chest pain is a common symptom encountered by emergency medical services . Aspirin increases survival in people with acute coronary syndrome and it

7743-745: The underlying diagnosis. Chest pain may also vary from person to person based upon age, sex, weight, and other differences. Chest pain may present as a stabbing, burning, aching, sharp, or pressure-like sensation in the chest. Chest pain may also radiate, or move, to several other areas of the body. This may include the neck, left or right arms, cervical spine , back, and upper abdomen . Other associated symptoms with chest pain can include nausea , vomiting , dizziness , shortness of breath , anxiety , and sweating . The type, severity, duration, and associated symptoms of chest pain can help guide diagnosis and further treatment. Causes of chest pain range from non-serious to serious to life-threatening. In adults

7832-414: 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

7921-401: 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,

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