heart (hahrt) cor; the viscus of cardiac muscle that maintains the circulation of the blood.
heart
heart [hahrt]
artificial heart a pumping mechanism that duplicates the rate, output, and blood pressure of the natural heart; it may replace the function of a part or all of the heart.
athletic heart hypertrophy of the heart without valvular disease, sometimes seen in athletes.
extracorporeal heart an artificial heart located outside the body and usually performing pumping and oxygenating functions.
fatty heart
1. one that has undergone fatty degeneration.
2. a condition in which fat has accumulated around and in the heart muscle.
fibroid heart one in which fibrous tissue replaces portions of the myocardium, such as may occur in chronic myocarditis.
horizontal heart a counterclockwise rotation of the electrical axis (deviation to the left) of the heart.
left heart the left atrium and ventricle, which propel the blood through the systemic circulation.
right heart the right atrium and ventricle, which propel the venous blood into the pulmonary circulation.
stone heart massive contraction band necrosis in an irreversibly noncompliant hypertrophied heart, occurring as a complication of cardiac surgery; believed due to low levels of ATP and to calcium overload.
three-chambered heart a developmental anomaly in which the heart is missing the interventricular or interatrial septum and so has only three compartments. 
)
Three-chambered heart in which the interventricular septum is absent (common ventricle).
water-bottle heart a radiographic sign of pericardial effusion, in which the cardiopericardial silhouette is enlarged and assumes the shape of a flask or water bottle.
| heart (härt) n. 1. The chambered, muscular organ in vertebrates that pumps blood received from the veins into the arteries, thereby maintaining the flow of blood through the entire circulatory system. 2. A similarly functioning structure in invertebrates. |   anterior view |
heart
Etymology: AS, heorte
the muscular cone-shaped hollow organ, about the size of a clenched fist, that pumps blood throughout the body and beats normally about 70 times per minute by coordinated nerve impulses and muscular contractions. Enclosed in pericardium, it rests on the diaphragm between the lower borders of the lungs, occupying the middle of the mediastinum. It is covered ventrally by the sternum and the adjoining parts of the third to the sixth costal cartilages. The organ is about 12 cm long, 8 cm wide at its broadest part, and 6 cm thick. The weight of the heart in men averages between 280 and 340 g and in women, between 230 and 280 g. The layers of the heart, starting from the outside, are the epicardium, the myocardium, and the endocardium. The chambers include two ventricles with thick muscular walls, making up the bulk of the organ, and two atria with thin muscular walls. A septum separates the ventricles and extends between the atria (interatrial septum), dividing the heart into the right and the left sides. The left side of the heart pumps oxygenated blood into the aorta and on to all parts of the body. The right side receives deoxygenated blood from the vena cava and pumps it into the pulmonary arteries. The valves of the heart include the tricuspid valve, the bicuspid (mitral) valve, the semilunar aortic valve, and the semilunar pulmonary valve. The sinoatrial node in the right atrium of the heart (under the control of the medulla oblongata in the brainstem) initiates the cardiac impulse, causing the atria to contract. The atrioventricular (AV) node near the septal wall of the right atrium spreads the impulse over the AV bundle (bundle of His) and its branches, causing the ventricles to contract. Both atria contract simultaneously, followed quickly by the simultaneous contraction of the ventricles. The sinoatrial node of the heartbeat sets the rate. Other factors affecting the heartbeat are emotion, exercise, hormones, temperature, pain, and stress. See also endocardium, epicardium, heart valve, myocardium.
heart [hahrt]
the hollow muscular organ lying slightly to the left of the midline of the chest. The heart serves as a pump controlling the blood flow in two circuits, the pulmonary and the systemic. See also circulatory system, and see Plates.
Divisions of the Heart. The septum, a thick muscular wall, divides the heart into right and left halves. Each half is again divided into upper and lower quarters or chambers. The lower chambers are called ventricles and the upper chambers are called atria. The right side of the heart, consisting of the right atrium and right ventricle, receives deoxygenated blood and sends it into the pulmonary circuit. The left side, consisting of the left atrium and left ventricle, receives oxygenated blood and sends it into the systemic circuit.
Valves of the Heart. The atrioventricular valves connect an atrium and a ventricle: between the right atrium and right ventricle is the tricuspid valve and between the left atrium and left ventricle is the mitral valve. The semilunar valves are valves at the blood's exit points from the heart: the pulmonary valve opens from the right ventricle into the pulmonary artery, and the aortic valve opens from the left ventricle into the aorta. These valves, both within the heart and leading out of it, open and shut in such a way as to keep the blood flowing in one direction through the heart's two separate pairs of chambers: fro atrium to ventricle and out through its appropriate artery.
Layers of the Heart. The heart wall is composed of three layers of tissues. Its chambers are lined by a delicate membrane, the endocardium. The thick muscular wall essential to normal pumping action of the heart is called the myocardium. The thin but sturdy membranous sac surrounding the exterior of the heart is called the pericardium.
The Heart's Pacemaker. The heart is made up of special muscle tissue, capable of continuous rhythmic contraction without tiring. The impulse that starts the contraction of the heart has its origin in an area of the right atrium called the sinoatrial node; it is this special tissue that acts as the normal pacemaker for the heart. The impulse is transmitted in a fraction of a second through the atria to another group of similarly sensitive fibers called the atrioventricular node, through the bundle of his, down the bundle branches, and to the Purkinje fibers, resulting in contraction of the ventricles.
Pumping Action. Although the right and left sides of the heart serve two separate branches of the circulation, each with its distinct function, they are coordinated so that the heart efficiently serves both sides with a single pumping action. The valve action on both sides is also coordinated with the two phases of the pumping action. Thus during diastole, the relaxation phase, oxygen-poor blood returning from the systemic circulation and accumulated in the right atrium pours into the right ventricle. At the same time, the oxygen-rich blood that has accumulated in the left atrium returning from the pulmonary circulation pours into the left ventricle. The walls of both atria contract to press blood into the relaxed ventricles. In the next contraction phase (systole), the valves between the atria and ventricles close and the ventricles contract, forcing the blood through the pulmonary artery and the aorta. At the end of the contraction the pulmonary and aortic valves snap shut, preventing any backward flow of the blood into the ventricles. Diastole follows, the ventricles again filling with the blood from their respective atria, and the cycle is repeated.
Disorders of the Heart. The heart is subject to a variety of disorders. Among them are congenital heart defects, which begin or exist at the time of birth. Disorders of this nature may interfere with the flow of the blood both within the heart and from the heart to the lungs. tetralogy of fallot and patent ductus arteriosus are examples of congenital heart defects. Rheumatic heart disease may be associated with rheumatic fever. Other disorders of the heart include angina pectoris, which is caused by coronary insufficiency; myocardial infarction, which results from formation of a blood clot in a coronary artery and death of myocardial tissue; and heart failure. Cardiac arrhythmias are disturbances in the normal rate and rhythm of the heartbeat.
Diagnostic Tests. Many different diagnostic procedures are available for the examination of the heart. Along with a history and physical examination, an electrocardiogram (ECG) is routinely obtained. It shows a tracing of the electrical excitation that spreads through the heart during each beat. It is the definitive source of information about cardiac arrhythmias, and also gives diagnostic information about myocardial infarctions.
Exercise stress testing is a valuable tool for detecting persons who have some degree of coronary heart disease. The test subject performs maximal exercise while being monitored by ECG. A positive stress test occurs when the subject cannot sustain the exercise for the duration of the test, cannot attain a normal maximal heart rate, or shows ECG changes indicative of ischemia. When stress testing is used for screening purposes, it is not diagnostic. However, persons with a positive stress test are 13 times more likely to develop significant coronary artery or heart disease and should work to reduce their risk factors. Stress testing is also used to evaluate the severity of known coronary disease and to guide the rehabilitation of a patient with coronary disease.
Phonocardiography is the recording of heart sounds and murmurs. It is more precise than auscultation with a stethoscope because it provides a permanent visual record that can be used to obtain precise timing information and can be used as baseline data for comparison with later findings.
Echocardiography is a type of diagnostic ultrasonography that provides information about the structure and function of the heart. It is a comfortable technique for the patient and is capable of establishing a diagnosis for several types of heart disease, especially those involving the valves. Types include M-mode, Doppler, and transesophageal echocardiography.
Several types of radioisotope examination are used to detect heart disease. A radioisotope imaging agent is injected into the patient, and a scintillation camera is then used to make an image of the distribution of radioactivity.
Thallium 201 has an affinity for heart tissue; when injected intravenously, it is carried to areas with adequate perfusion. Myocardial infarcts and areas of acute ischemia or scarring appear as “cold spots” (areas of no uptake of thallium) on the scintigram. When the isotope is injected during maximal exercise in an exercise stress test, the scan shows areas of inadequate perfusion and is a better indicator of coronary disease than a stress test alone.
Radiopharmaceuticals that label the blood pool can be used with a computerized scintillation camera to evaluate ventricular performance. Images of the first pass of the radioisotope through the heart can be used to determine the cardiac output and ejection fraction, the size of the ventricles, and regional wall motion.
The imaging agents used for bone scans, such as technetium 99m pyrophosphate or diphosphonate, also have an affinity for areas of acute ischemic tissue damage. “Hot spots” on the scintigram (areas of isotope uptake) show areas of acute infarction. The scan is usually negative by approximately 6 days after an infarction.
Cardiac catheterization is an invasive technique used when definitive data are required to decide whether heart disease should be treated medically, surgically, or through interventional cardiology techniques such as percutaneous transluminal angioplasty, stents, or valvuloplasty. A catheter is inserted into a vein or artery, usually the brachial artery or the femoral vein or artery, and guided into the heart. Tracings of the pressure pulses within the chambers during the heart cycle are obtained. Cardiac output, pulmonary artery pressures, the orifice area of valves, and the degree of left-to-right shunting can be determined.
Angiocardiography is the x-ray examination of the heart after injection of a radiopaque contrast medium through a catheter at various locations in the heart. The films show the size and motion of the heart chambers and can demonstrate aortic or mitral regurgitation. In coronary arteriography the contrast medium is injected through a catheter into the orifice of each coronary artery. The films show atherosclerotic obstructions of the arteries and are useful in planning coronary bypass surgery, percutaneous transluminal angioplasty, or stents.
Exercise stress testing is a valuable tool for detecting persons who have some degree of coronary heart disease. The test subject performs maximal exercise while being monitored by ECG. A positive stress test occurs when the subject cannot sustain the exercise for the duration of the test, cannot attain a normal maximal heart rate, or shows ECG changes indicative of ischemia. When stress testing is used for screening purposes, it is not diagnostic. However, persons with a positive stress test are 13 times more likely to develop significant coronary artery or heart disease and should work to reduce their risk factors. Stress testing is also used to evaluate the severity of known coronary disease and to guide the rehabilitation of a patient with coronary disease.
Phonocardiography is the recording of heart sounds and murmurs. It is more precise than auscultation with a stethoscope because it provides a permanent visual record that can be used to obtain precise timing information and can be used as baseline data for comparison with later findings.
Echocardiography is a type of diagnostic ultrasonography that provides information about the structure and function of the heart. It is a comfortable technique for the patient and is capable of establishing a diagnosis for several types of heart disease, especially those involving the valves. Types include M-mode, Doppler, and transesophageal echocardiography.
Several types of radioisotope examination are used to detect heart disease. A radioisotope imaging agent is injected into the patient, and a scintillation camera is then used to make an image of the distribution of radioactivity.
Thallium 201 has an affinity for heart tissue; when injected intravenously, it is carried to areas with adequate perfusion. Myocardial infarcts and areas of acute ischemia or scarring appear as “cold spots” (areas of no uptake of thallium) on the scintigram. When the isotope is injected during maximal exercise in an exercise stress test, the scan shows areas of inadequate perfusion and is a better indicator of coronary disease than a stress test alone.
Radiopharmaceuticals that label the blood pool can be used with a computerized scintillation camera to evaluate ventricular performance. Images of the first pass of the radioisotope through the heart can be used to determine the cardiac output and ejection fraction, the size of the ventricles, and regional wall motion.
The imaging agents used for bone scans, such as technetium 99m pyrophosphate or diphosphonate, also have an affinity for areas of acute ischemic tissue damage. “Hot spots” on the scintigram (areas of isotope uptake) show areas of acute infarction. The scan is usually negative by approximately 6 days after an infarction.
Cardiac catheterization is an invasive technique used when definitive data are required to decide whether heart disease should be treated medically, surgically, or through interventional cardiology techniques such as percutaneous transluminal angioplasty, stents, or valvuloplasty. A catheter is inserted into a vein or artery, usually the brachial artery or the femoral vein or artery, and guided into the heart. Tracings of the pressure pulses within the chambers during the heart cycle are obtained. Cardiac output, pulmonary artery pressures, the orifice area of valves, and the degree of left-to-right shunting can be determined.
Angiocardiography is the x-ray examination of the heart after injection of a radiopaque contrast medium through a catheter at various locations in the heart. The films show the size and motion of the heart chambers and can demonstrate aortic or mitral regurgitation. In coronary arteriography the contrast medium is injected through a catheter into the orifice of each coronary artery. The films show atherosclerotic obstructions of the arteries and are useful in planning coronary bypass surgery, percutaneous transluminal angioplasty, or stents.
Prevention of Heart Disease. Although heart disease remains the leading cause of death in industrialized countries, its mortality rate has steadily declined since the early 1970s. A major factor in this decline is the development of more effective preventive measures and modes of treatment for ischemic heart disease. These advances include open heart surgery to repair congenital defects and replace malfunctioning valves; vascular surgery to repair or bypass obstructions in the coronary arteries and aorta; newer and more accurate diagnostic tests and procedures for detecting problems involving the heart and blood vessels; antimicrobial therapy for the treatment of rheumatic fever, syphilis, and other infectious diseases that are damaging to the heart; more sophisticated monitoring equipment and intensive care units; and aggressive medical treatment and management of heart disease and hypertension.
All these contributions to the control and correction of cardiovascular diseases are important in the reduction of mortality rates and improvement in patients' quality of life. Nevertheless, it is also important for prevention that there be an improvement of the general public's awareness of the causes and risk factors of cardiac disorders. Major risk factors that can be avoided, modified, or corrected include cigarette smoking, elevated blood lipids, obesity, habitual dietary excesses, lack of exercise, hypertension, and excessive stress. Health professionals can promote reduction in the incidence of heart disease by educating the public about these risk factors and by encouraging active participation in preventive measures, particularly in those that involve changes in lifestyle.
All these contributions to the control and correction of cardiovascular diseases are important in the reduction of mortality rates and improvement in patients' quality of life. Nevertheless, it is also important for prevention that there be an improvement of the general public's awareness of the causes and risk factors of cardiac disorders. Major risk factors that can be avoided, modified, or corrected include cigarette smoking, elevated blood lipids, obesity, habitual dietary excesses, lack of exercise, hypertension, and excessive stress. Health professionals can promote reduction in the incidence of heart disease by educating the public about these risk factors and by encouraging active participation in preventive measures, particularly in those that involve changes in lifestyle.
Blood enters the right atrium from the body and then passes into the right ventricle, where it is pumped into the lungs. It returns from the lungs into the right atrium. It enters the left ventricle and then is pumped to the body via the aorta.
heart,
n the muscular pump that maintains and regulates the flow of blood through the body.
heart, artificial,
n a mechanical device that acts to pump blood to and from the body tissues during repair of the heart.
heart attack,
heart block,
n the condition in which the muscular interconnection between the auricle and ventricle is interrupted so that the auricle and ventricle beat independently of each other.
heart, compression of,
n See massage, cardiac.
heart defect,
n a fault in the structural integrity of the heart.
heart defect, congenital,
n the structural errors in the heart formed during embryonic and fetal life.
heart disease,
n a disorder in the normal functioning of the heart.
heart disease, dental concerns,
n.pl the special considerations taken to eliminate oral disease by maintaining an elevated level of oral health and prevent infective endocarditis, an infection of the heart valves that may be caused by bacteremia created during dental treatments. Heart disease has also been linked with increased levels of periodontal disease.
heart disease, ischemic,
heart disease risk factors,
n.pl the hereditary, lifestyle, and environmental influences that increase one's chances of developing heart disease.
heart massage,
n See massage, cardiac.
heart murmur,
n the sound of blood flowing back through a defective heart valve. Two types are possible: organic or functional.
heart, normal,
n a heart without anatomic defects that could cause an impairment in the function of the organ.
heart rate,
n the rate or tempo of heart contractions recorded in beats per minute.
heart sounds,
n.pl the normal noises produced within the heart during the cardiac cycle that can be heard over the precordium and may reveal abnormalities in cardiac structure or function. The use of the stethoscope over the left side of the chest is a common clinical technique to assess heart function. The typical sounds are a rythmic lub dup; abnormal sounds include clicks, murmurs, rubs, snaps, and gallops.
heart surgery,
n a surgical procedure involving the heart, performed to correct acquired or congenital defects, to replace diseased valves, to open or bypass blocked vessels, or to graft a prosthesis or a transplant in place.
heart valves,
n.pl one of the four structures within the heart that prevent backflow of blood by opening and closing with each heartbeat. They include two semilunar valves, the aortic and pulmonary; the mitral, or bicuspid, valve; and the tricuspid valve. They permit the flow of blood in only one direction, and any one of the valves may become defective, permitting the backflow associated with heart murmurs.
heart
the hollow muscular organ lying on the sternum that serves as a pump controlling the blood flow in two circuits, the pulmonary and the systemic. See also circulatory system.
artificial heart
a mechanical device that replaces the heart by using pulsating air to pump blood to the body. Successfully placed in calves, sheep and dogs as experimental models for the subsequent use of such methods in humans.
heart attack
see myocardial infarction.
heart bones
ossicles in the fibrous skeletal ring which surrounds the aortic orifice of the heart in cattle and occasionally in other species; called also ossa cordis.
heart conducting system
consists of the sinoatrial node, the atrioventricular node, the atrioventricular bundle and its two crura.
cyanotic heart malformations
insufficient oxygenated hemoglobin is received in the peripheral capillary beds resulting in blue discoloration of tissues, and an incapacity of the body to maintain a life-sustaining level of activity.
heart disease
an all-embracing term including those diseases in which there is intrinsic disease of the heart such as uremia, valvular disease, African horse sickness, vitamin E-selenium nutritional deficiency, inherited cardiomyopathies of dogs and cattle, altitude sickness, canine parvovirus infection, and in a number of plant and other poisonings. See also mulberry heart disease.
heart failure cells
hemosiderin-laden macrophages present in the pulmonary alveoli in cases of congestive heart failure.
heart malformations
includes ectopia cordis, patent foramen ovale, ventricular septal defects such as Fallot's tetralogy, Eisenmenger complex, patent ductus arteriosus, aortic coarctation, right aortic arch persistence, truncus arteriosus persistence, fibroelastosis, subvalvular aortic stenosis, anomalous origin of carotid arteries, transposition of great vessels, pulmonic stenosis, aortic stenosis.
heart massage
see cardiac massage.
heart meridian points
acupuncture points along the heart meridian.
heart rate
the number of contractions of the cardiac ventricles per unit of time. For normal rates see pulse rate.
heart score
a concept which sets out that performance in racing horses is related to heart size, now a well-established relationship, and that heart size can be estimated in the living horse by the measurement of the QRS interval.
heart sounds
see heart sounds, heart murmur.
heart strain
is an unpopular concept in any medical science but overtrained horses which perform poorly do have a high incidence of abnormal T waves.
heart valve anomalies
failure of complete development of atrioventricular or semilunar valves results in stenosis or incompetence of the valves and often congestive heart failure.
heart valve hematoma
congenital, usually multiple lesions on the edges of atrioventricular valves, mostly in calves; disappear spontaneously in most cases.
heart valve thrombosis
common lesion on the free edges of valves, often the source of widespread emboli; on healing leave scarred, insufficient valves.
heart valves
flaps of endothelial connective tissue that guard the entrance into and exit from the ventricles and bring about unidirectional blood flow. Include the atrioventricular and semilunar valves, the proper closure of which is essential to maintain circulatory equilibrium, can be diseased and cause heart failure. See also heart murmur, endocarditis, endocardiosis.
heart
See Abiomed implantable heart, Athlete's heart, Baby Fae heart, Bleeding heart, Crisscross heart, Dextroposition heart, Depraved heart, Egg-shaped heart, Flabby heart, Flask-shaped heart, Holiday heart, Left heart, Mongolian
heart, Old soldier's heart, Penn State heart, Right heart, Sabot heart, Second heart, Stone heart, Swinging heart, Water bottle heart.
HEART
Cardiology A clinical trial–Healing & Early Afterload Reducing Therapy
Patient discussion about heart.
Q. How to get rid of a heart burn? Help! I have constant heart burn, how to make it go away?
A. try a glass of water with a teaspoon of baking soda.instant relief.
Q. What Is the Treatment for Congestive Heart Failure? My mother is 76 years ols and has been suffering from a heart disease for many years. Lately she has developed congestive heart failure. How is this situation treated?
A. The treatment of CHF focuses on treating the symptoms and signs of CHF and preventing the progression of disease. If there is a reversible cause of the heart failure (an infection, alcohol consumption, anemia, arrhythmia, or hypertension), that should be addressed as well. Treatments include exercise, eating healthy foods, reduction in salty foods, and abstinence from smoking and drinking alcohol.
Q. Heart serious, Lungs swollen. My brother Bennet, seventeen, and it is birthday tomorrow. But I guess he already got his seventeenth birthday present: lupus. He is recently diagnosed with lupus, yet some complications are still under-diagnosed. He have always had huge aspirations. Now, as my health deterioates at a weird rate, he can't walk around. His heart is in serious condition, his lungs are swollen, so are his joints. His voice is almost not there and he is, thinking about his eighteenth birthday. His face is swollen, as some gland in his neck has bloated and somehow he don't enjoy what he see in the mirror he says. He is very sensitive to sunlight and so he stay in for all day and when he decide to go out, it is after 8 or 9 p.m. He is despondent, yes. Because he see his dreams shattering, his family life is breaking apart and he feels as if he is getting more useless EVERY single day. How long will he continue? Maybe another thirty years...maybe not another day. Could anyone help him to SURV
A. Sorry to hear about your brother being so miserable with his symptoms, and the apparent distress it understandably is causing you.
With sunlight bothering him, that is called photophobia and is a symptom of certain types of lupus, or can be an effect from a medication he may be taking. The swelling on his neck may be due to hyperthyroidism, asthma, or an allergic reaction perhaps to prednisone, which is given to lupus patients.
You should get your bother to see a doctor soon, if you have not already. You don't want him to stop breathing or anything.
Dan
Read more or ask a question about heartWith sunlight bothering him, that is called photophobia and is a symptom of certain types of lupus, or can be an effect from a medication he may be taking. The swelling on his neck may be due to hyperthyroidism, asthma, or an allergic reaction perhaps to prednisone, which is given to lupus patients.
You should get your bother to see a doctor soon, if you have not already. You don't want him to stop breathing or anything.
Dan
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