|
Mitral Valve Replacement
Mitral valve replacement is a procedure whereby the diseased mitral valve of a patient's heart is replaced by either a mechanical or tissue (bioprosthetic) valve. The mitral valve may need to be replaced because: * The valve is leaky (mitral valve regurgitation) * The valve is narrowed and doesn't open properly (mitral valve stenosis) Causes of mitral valve disease include infection, calcification and inherited collagen disease. Current mitral valve replacement approaches include open heart surgery and minimally invasive cardiac surgery (MICS). Normal mitral valve anatomy and physiology The mitral valve is a bileaflet valve sited between the left atrium and left ventricle, responsible for preventing blood flowing from the ventricle to the atrium when the heart contracts. It is elliptical, and its area varies from 5.0 to 11.4 cm2. The valve leaflets are separated by two commissures, and each leaflet of the valve (anterior leaflet, the large one, and posterior leaflet, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitral Valve
The mitral valve (), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-way valves allowing blood flow in just one direction. The mitral valve and the tricuspid valve are known as the atrioventricular valves because they lie between the atria and the ventricles. In normal conditions, blood flows through an open mitral valve during diastole with contraction of the left atrium, and the mitral valve closes during systole with contraction of the left ventricle. The valve opens and closes because of pressure differences, opening when there is greater pressure in the left atrium than ventricle and closing when there is greater pressure in the left ventricle than atrium. In abnormal conditions, blood may flow backward through the valve ( mitral regurgitation) or the mitral valve may be narrowed (mitral stenosis). Rh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systemic Circulation
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek ''kardia'' meaning ''heart'', and from Latin ''vascula'' meaning ''vessels''). The circulatory system has two divisions, a systemic circulation or circuit, and a pulmonary circulation or circuit. Some sources use the terms ''cardiovascular system'' and ''vascular system'' interchangeably with the ''circulatory system''. The network of blood vessels are the great vessels of the heart including large elastic arteries, and large veins; other arteries, smaller arterioles, capillaries that join with venules (small veins), and other veins. The circulatory system is closed in vertebrates, which means that the blood never leaves the network of blood vessels. Some invertebrates such as arthro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Ventilator
A ventilator is a piece of health technology, medical technology that provides mechanical ventilation by moving breathable air into and out of the lungs, to deliver breaths to a patient who is physically unable to breathe, or breathing insufficiently. Ventilators are computerized microprocessor control, microprocessor-controlled machines, but patients can also be ventilated with a simple, hand-operated bag valve mask. Ventilators are chiefly used in intensive-care medicine, home care, and emergency medicine (as standalone units) and in anesthesiology (as a component of an anesthesia machine). Ventilators are sometimes called "respirators", a term commonly used for them in the 1950s (particularly the Forrest Bird#Mechanical ventilators, "Bird respirator"). However, contemporary medical terminology uses the word "respirator" to refer instead to a face-mask that protects wearers against hazardous airborne substances. Function In its simplest form, a modern positive pressure venti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intensive Care Unit
220px, Intensive care unit An intensive care unit (ICU), also known as an intensive therapy unit or intensive treatment unit (ITU) or critical care unit (CCU), is a special department of a hospital or health care facility that provides intensive care medicine. Intensive care units cater to patients with severe or life-threatening illnesses and injuries, which require constant care, close supervision from life support equipment and medication in order to ensure normal bodily functions. They are staffed by highly trained physicians, nurses and respiratory therapists who specialize in caring for critically ill patients. ICUs are also distinguished from general hospital wards by a higher staff-to-patient ratio and access to advanced medical resources and equipment that is not routinely available elsewhere. Common conditions that are treated within ICUs include acute respiratory distress syndrome, septic shock, and other life-threatening conditions. Patients may be referred dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardioplegia
Cardioplegia is intentional and temporary cessation of cardiac activity, primarily for cardiac surgery. Overview The word ''cardioplegia'' combines the Greek ''cardio'' meaning the "heart", and ''plegia'' "paralysis". Technically, this means arresting or stopping the heart so that surgical procedures can be done in a still and bloodless field. Most commonly, however, the word ''cardioplegia'' refers to the solution used to bring about asystole of the heart, or heart paralysis. One of the first physicians to use the term cardioplegia was Dr. Lam in 1957. However his work on the myocardial protection was preceded serendipitously by Sydney Ringer in the late 1800s. At that time Ringer and colleagues noticed that tap water had the ability to increase contractility of the heart, likely due to its high calcium content. Sydney Ringer also commented on the importance of potassium ion concentration on depressing intrinsic heart rhythm. Through a series of experiments performed on frog a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiopulmonary Bypass
Cardiopulmonary bypass (CPB) is a technique in which a machine temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and oxygen to the body. The CPB pump itself is often referred to as a heart–lung machine or "the pump". Cardiopulmonary bypass pumps are operated by perfusionists. CPB is a form of extracorporeal circulation. Extracorporeal membrane oxygenation is generally used for longer-term treatment. CPB mechanically circulates and oxygenates blood for the body while bypassing the heart and lungs. It uses a heart–lung machine to maintain perfusion to other body organs and tissues while the surgeon works in a bloodless surgical field. The surgeon places a cannula in the right atrium, vena cava, or femoral vein to withdraw blood from the body. Venous blood is removed from the body by the cannula and then filtered, cooled or warmed, and oxygenated before it is returned to the body by a mechanical pump. The cannula used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Breastbone
The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest and longest flat bones of the body. Its three regions are the manubrium, the body, and the xiphoid process. The word "sternum" originates from the Ancient Greek στέρνον (stérnon), meaning "chest". Structure The sternum is a narrow, flat bone, forming the middle portion of the front of the chest. The top of the sternum supports the clavicles (collarbones) and its edges join with the costal cartilages of the first two pairs of ribs. The inner surface of the sternum is also the attachment of the sternopericardial ligaments. Its top is also connected to the sternocleidomastoid muscle. The sternum consists of three main parts, listed from the top: * Manubrium * Body (gladiolus) * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diastole
Diastole ( ) is the relaxed phase of the cardiac cycle when the chambers of the heart are re-filling with blood. The contrasting phase is systole when the heart chambers are contracting. Atrial diastole is the relaxing of the atria, and ventricular diastole the relaxing of the ventricles. The term originates from the Greek word (''diastolē''), meaning "dilation", from (''diá'', "apart") + (''stéllein'', "to send"). Role in cardiac cycle A typical heart rate is 75 beats per minute (bpm), which means that the cardiac cycle that produces one heartbeat, lasts for less than one second. The cycle requires 0.3 sec in ventricular systole (contraction)—pumping blood to all body systems from the two ventricles; and 0.5 sec in diastole (dilation), re-filling the four chambers of the heart, for a total of 0.8 sec to complete the cycle. Early ventricular diastole During early ventricular diastole, pressure in the two ventricles begins to drop from the peak reached during systo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paroxysmal Nocturnal Dyspnoea
Paroxysmal nocturnal dyspnea or paroxysmal nocturnal dyspnoea (PND) is an attack of severe shortness of breath and coughing that generally occurs at night. It usually awakens the person from sleep, and may be quite frightening. PND, as well as simple orthopnea, may be relieved by sitting upright at the side of the bed with legs dangling, as symptoms typically occur when the person is recumbent, or lying down. Risk Factors Since paroxysmal nocturnal dyspnea occurs mainly because of heart or lung problems, common risk factors include those that affect the function of the heart and lungs. Risk factors for cardiac diseases include high blood pressure, high cholesterol, diabetes, obesity, and a lifestyle lacking exercise and a healthy diet. Risk factors for lung diseases include tobacco use, including second hand smoke, pollution, exposure to hazardous fumes, and allergens. Mechanism PND can be explained by mechanisms similar to those of orthopnea and typical dyspnea. When a person is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthopnea
Orthopnea or orthopnoea is shortness of breath (dyspnea) that occurs when lying flat, causing the person to have to sleep propped up in bed or sitting in a chair. It is commonly seen as a late manifestation of heart failure, resulting from fluid redistribution into the central circulation, causing an increase in pulmonary capillary pressure and causing difficulty in breathing. It is also seen in cases of abdominal obesity or pulmonary disease. Orthopnea is the opposite of platypnea, shortness of breath that worsens when sitting or standing upright. Causes Orthopnea is often a symptom of left ventricular heart failure and/or cardiogenic pulmonary edema. It can also occur in those with asthma and chronic bronchitis, as well as those with sleep apnea or panic disorder. It is also as associated with polycystic liver disease. From a neuromuscular perspective, orthopnea is potentially a sign of severe diaphragmatic weakness. Under such circumstances, patients may describe shortness of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortness Of Breath
Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity", and recommends evaluating dyspnea by assessing the intensity of its distinct sensations, the degree of distress and discomfort involved, and its burden or impact on the patient's activities of daily living. Distinct sensations include effort/work to breathe, chest tightness or pain, and "air hunger" (the feeling of not enough oxygen). The tripod position is often assumed to be a sign. Dyspnea is a normal symptom of heavy physical exertion but becomes pathological if it occurs in unexpected situations, when resting or during light exertion. In 85% of cases it is due to asthma, pneumonia, cardiac ischemia, interstitial lung disease, congestive heart failure, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
