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Volume Overload
Volume overload refers to the state of one of the chambers of the heart in which too large a volume of blood exists within it for it to function efficiently. Ventricular volume overload is approximately equivalent to an excessively high preload. It is a cause of cardiac failure. Pathophysiology In accordance with the Frank–Starling law of the heart, the myocardium contracts more powerfully as the end-diastolic volume increases. Stretching of the myofibrils in cardiac muscle causes them to contract more powerfully due to a greater number of cross-bridges being formed between the myofibrils within cardiac myocytes.Klabunde, Richard E. "Cardiovascular Physiology Concepts". Lippincott Williams & Wilkins, 2011, p. 74. This is true up to a point, however beyond this there is a loss of contractile ability due to loss of connection between myofibrils; see figure. Various pathologies, listed below, can lead to volume overload. Different mechanisms are involved depending on the caus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Response Of Cardiac Stroke Volume To Ventricular Filling Under Normal Conditions
Response may refer to: *Call and response (music), musical structure *Reaction (other) *Request–response **Output or response, the result of telecommunications input *Response (liturgy), a line answering a versicle *Response (music) or antiphon, a response to a psalm or other part of a religious service *Response, a phase in emergency management * Response rate (survey) Proper names and titles *''Response'', a print and online magazine of Christian thought published by Seattle Pacific University * ''Response'' (album), a studio album by Phil Wickham *Response (company), a call centre company based in Scotland * ''The Response'' (film) *The National War Memorial (Canada), titled ''The Response'' *The Northumberland Fusiliers Memorial in Newcastle upon Tyne, titled "The Response" See also *Action (other) *Answer (other) *Reply (other) *Response variable, or the realization thereof *Responsions, an examination formerly required for a degree at O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aortic Regurgitation
Aortic regurgitation (AR), also known as aortic insufficiency (AI), is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle. As a consequence, the cardiac muscle is forced to work harder than normal. Signs and symptoms Symptoms of aortic regurgitation are similar to those of heart failure and include the following: * Dyspnea on exertion * Orthopnea * Paroxysmal nocturnal dyspnea * Palpitations * Angina pectoris * Cyanosis (in acute cases) Causes In terms of the cause of aortic regurgitation, is often due to the aortic root dilation ('' annuloaortic ectasia''), which is idiopathic in over 80% of cases, but otherwise may result from aging, syphilitic aortitis, osteogenesis imperfecta, aortic dissection, Behçet's disease, reactive arthritis and systemic hypertension.Chapter 1: Diseases of the Cardiovascular system > Section: Valvular Heart Disease in: Aortic root dilation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, and leg swelling. The shortness of breath may occur with exertion or while lying down, and may wake people up during the night. Chest pain, including angina, is not usually caused by heart failure, but may occur if the heart failure was caused by a heart attack. The severity of the heart failure is measured by the severity of symptoms during exercise. Other conditions that may have symptoms similar to heart failure include obesity, kidney failure, liver disease, anemia, and thyroid disease. Common causes of heart failure include coronary artery disease, heart attack, high blood pressure, atrial fibrillation, valvular heart disease, excessive alcohol consumption, infection, and cardiomyopathy. These cause heart failure by altering the s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrial Septal Defect
Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria (upper chambers) of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA). After PFO closure the atria normally are separated by a dividing wall, the interatrial septum. If this septum is defective or absent, then oxygen-rich blood can flow directly from the left side of the heart to mix with the oxygen-poor blood in the right side of the heart; or the opposite, depending on whether the left or right atrium has the higher blood pressure. In the absence of other heart defects, the left atrium has the higher pressure. This can lead to lower-than-normal oxygen levels in the arterial blood that supplies the brain, organs, and tissues. However, an ASD m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pulmonary Regurgitation
Pulmonary (or pulmonic) insufficiency (or incompetence, or regurgitation) is a condition in which the pulmonary valve is incompetent and allows backflow from the pulmonary artery to the right ventricle of the heart during diastole. While a small amount of backflow may occur ordinarily, it is usually only shown on an echocardiogram and is harmless. More pronounced regurgitation that is noticed through a routine physical examination is a medical sign of disease and warrants further investigation. If it is secondary to pulmonary hypertension it is referred to as a Graham Steell murmur. Signs and symptoms Because pulmonic regurgitation is the result of other factors in the body, any noticeable symptoms are ultimately caused by an underlying medical condition rather than the regurgitation itself. However, more severe regurgitation may contribute to right ventricular enlargement by dilation, and in later stages, right heart failure. A diastolic decrescendo murmur can sometimes be ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tricuspid Regurgitation
Tricuspid regurgitation (TR), also called tricuspid insufficiency, is a type of valvular heart disease in which the tricuspid valve of the heart, located between the right atrium and right ventricle, does not close completely when the right ventricle contracts (systole). TR allows the blood to flow backwards from the right ventricle to the right atrium, which increases the volume and pressure of the blood both in the right atrium and the right ventricle, which may increase central venous volume and pressure if the backward flow is sufficiently severe. The causes of TR are divided into ''hereditary'' and ''acquired''; and also ''primary'' and ''secondary''. Primary TR refers to a defect solely in the tricuspid valve, such as infective endocarditis; secondary TR refers to a defect in the valve as a consequence of some other pathology, such as left ventricular failure or pulmonary hypertension. The mechanism of TR is either a dilatation of the base (annulus) of the valve due to righ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemodialysis
Hemodialysis, also spelled haemodialysis, or simply dialysis, is a process of purifying the blood of a person whose kidneys are not working normally. This type of dialysis achieves the extracorporeal removal of waste products such as creatinine and urea and free water from the blood when the kidneys are in a state of kidney failure. Hemodialysis is one of three renal replacement therapies (the other two being kidney transplant and peritoneal dialysis). An alternative method for extracorporeal separation of blood components such as plasma or cells is apheresis. Hemodialysis can be an outpatient or inpatient therapy. Routine hemodialysis is conducted in a dialysis outpatient facility, either a purpose-built room in a hospital or a dedicated, stand-alone clinic. Less frequently hemodialysis is done at home. Dialysis treatments in a clinic are initiated and managed by specialized staff made up of nurses and technicians; dialysis treatments at home can be self-initiated and managed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giant Hepatic Haemangioma
A cavernous liver hemangioma or hepatic hemangioma is a benign tumor of the liver composed of hepatic endothelium, endothelial cells. It is the most common benign liver tumour, and is usually asymptomatic and diagnosed incidentally on radiological imaging. Liver hemangiomas are thought to be congenital in origin.Baron R'Liver: Masses Part I: detection and characterization'. The Radiology Assistant 2006 Several subtypes exist, including the giant hepatic haemangioma, which can cause significant complications. Diagnosis Liver hemangiomas are typically hyperechoic on Medical ultrasonography, ultrasound though may occasionally be hypoechoic; ultrasound is not diagnostic. Computed tomography (CT),Brodsky RI, Friedman AC, Maurer AH et-al. Hepatic cavernous hemangioma: diagnosis with 99mTc-labeled red cells and single-photon emission CT. ''AJR Am J Roentgenol''. 1987;148 (1): 125-9. magnetic resonance imaging (MRI)Vilanova JC, Barceló J, Smirniotopoulos JG et-al. Hemangioma from head t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arteriovenous Fistula
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm. Clinical features Pathological Hereditary hemorrhagic telangiectasia is a condition where there is direct connection between arterioles and venules without intervening capillary beds, at the mucocutaneous region and internal bodily organs. Those who are affected by this conditions usually do not experience any symptoms. Difficulty in breathing is the most common symptom for those who experience symptoms. Just like berry aneurysm, a cerebral arteriovenous malformation can rupture causing subarachnoid hemorrhage. Causes The cause of this condition include * Congenital (developmental defect) * Rupture of arterial aneurysm into an adjacent vein * Penetrating injuries * Inflammatory necrosis of adjacent vessels * Complication of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arteriovenous Malformation
Arteriovenous malformation is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system (usually cerebral AVM), but can appear in any location. Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems. AVMs are usually congenital and belong to the RASopathies. The genetic transmission patterns of AVMs are incomplete, but there are known genetic mutations (for instance in the epithelial line, tumor suppressor PTEN gene) which can lead to an increased occurrence throughout the body. Signs and symptoms Symptoms of AVM vary according to the location of the malformation. Roughly 88% of people with an AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder (called in medicine an "incidental finding"); in rare cases, its expansion or a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventricular Septal Defect
A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one common ventricle. The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes. The membranous portion, which is close to the atrioventricular node, is most commonly affected in adults and older children in the United States. It is also the type that will most commonly require surgical intervention, comprising over 80% of cases. Membranous ventricular septal defects are more common than muscular ventricular septal defects, and are the most common congenital cardiac anomaly. Signs and symptoms Ventricular septal defect is usually symptomless at birth. It usually manifests a few weeks after birth. VSD is an acyanotic congenital heart defect, aka a lef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patent Ductus Arteriosus
''Patent ductus arteriosus'' (PDA) is a medical condition in which the ''ductus arteriosus'' fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has a higher pressure, to the pulmonary artery. Symptoms are uncommon at birth and shortly thereafter, but later in the first year of life there is often the onset of an increased work of breathing and failure to gain weight at a normal rate. With time, an uncorrected PDA usually leads to pulmonary hypertension followed by right-sided heart failure. The ''ductus arteriosus'' is a fetal blood vessel that normally closes soon after birth. In a PDA, the vessel does not close, but remains ''patent'' (open), resulting in an abnormal transmission of blood from the aorta to the pulmonary artery. PDA is common in newborns with persistent respiratory problems such as hypoxia, and has a high occurrence in premature newborns. Premature newborns are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
