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Sick Sinus Syndrome
Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart rates. Signs and symptoms Often sinus node dysfunction produces no symptoms, especially early in the disease course. Signs and symptoms usually appear in more advanced disease and more than 50% of patients will present with syncope or transient near-fainting spells as well as bradycardias that are accompanied by rapid heart rhythms, referred to as tachycardia-bradycardia syndrome Other presenting signs or symptoms can include confusion, fatigue, palpitations, chest pain, shortness of breath, headache, and nausea. Patients can also present with symptoms of congestive heart failure, stroke or transient ischemic attacks due to the abnormal rhythm. Compli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pacemaker
An artificial cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural cardiac pacemaker) or pacemaker is a medical device that generates electrical impulses delivered by electrodes to the chambers of the heart either the upper atria, or lower ventricles to cause the targeted chambers to contract and pump blood. By doing so, the pacemaker regulates the function of the electrical conduction system of the heart. The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system. Modern pacemakers are externally programmable and allow a cardiologist, particularly a cardiac electrophysiologist, to select the optimal pacing modes for individual patients. Most pacemakers are on demand, in which the stimulation of the heart is based on the dynamic demand of the circulatory system. Others send out a fixed rate of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SA Block
A sinoatrial block (also spelled sinuatrial block) is a disorder in the normal rhythm of the heart, known as a heart block, that is initiated in the sinoatrial node. The initial action potential, action impulse in a heart is usually formed in the sinoatrial node (SA node) and carried through the atria, down the internodal atrial pathways to the atrioventricular node (AV) node. In normal conduction, the impulse would travel across the bundle of His (AV bundle), down the bundle branches, and into the Purkinje fibers. This would depolarize the ventricles and cause them to contract. In an SA block, the electrical impulse is delayed or blocked on the way to the atria, thus delaying the atrial beat. (An Atrioventricular block, AV block, occurs in the AV node and delays ventricular depolarisation). SA blocks are categorized into three classes based on the length of the delay. Symptoms Sinoatrial blocks are typically well tolerated. They are not as serious as an AV block and most often d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Channel Blocker
Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists are a group of medications that disrupt the movement of calcium () through calcium channels. Calcium channel blockers are used as antihypertensive drugs, i.e., as medications to decrease blood pressure in patients with hypertension. CCBs are particularly effective against large vessel stiffness, one of the common causes of elevated systolic blood pressure in elderly patients. Calcium channel blockers are also frequently used to alter heart rate (especially from atrial fibrillation), to prevent peripheral and cerebral vasospasm, and to reduce chest pain caused by angina pectoris. N-type, L-type, and T-type voltage-dependent calcium channels are present in the zona glomerulosa of the human adrenal gland, and CCBs can directly influence the biosynthesis of aldosterone in adrenocortical cells, with consequent impact on the clinical treatment of hypertension with these agents. CCBs have b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Blocker
Beta blockers, also spelled β-blockers, are a class of medications that are predominantly used to manage cardiac arrhythmia, abnormal heart rhythms, and to protect the heart from a second myocardial infarction, heart attack after a first heart attack (preventative healthcare, secondary prevention). They are also widely used to treat hypertension, high blood pressure, although they are no longer the first choice for initial treatment of most patients. Beta blockers are competitive antagonists that block the receptor sites for the endogenous catecholamines Adrenaline, epinephrine (adrenaline) and norepinephrine (noradrenaline) on beta receptor, adrenergic beta receptors, of the sympathetic nervous system, which mediates the fight-or-flight response. Some block activation of all types of β-adrenergic receptors and others are selective for one of the three known types of beta receptors, designated β1, β2 and β3 receptors. Beta-1 adrenergic receptor, β1-adrenergic receptors are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCN5A
Sodium channel protein type 5 subunit alpha, also known as NaV1.5 is an integral membrane protein and tetrodotoxin-resistant voltage-gated sodium channel subunit. NaV1.5 is found primarily in cardiac muscle, where it mediates the fast influx of Na+-ions (INa) across the cell membrane, resulting in the fast depolarization phase of the cardiac action potential. As such, it plays a major role in impulse propagation through the heart. A vast number of cardiac diseases is associated with mutations in NaV1.5 (see paragraph genetics). ''SCN5A'' is the gene that encodes the cardiac sodium channel NaV1.5. Gene structure SCN5A is a highly conserved gene located on human chromosome 3, where it spans more than 100 kb. The gene consists of 28 exons, of which exon 1 and in part exon 2 form the 5' untranslated region ( 5’UTR) and exon 28 the 3' untranslated region ( 3’UTR) of the RNA. SCN5A is part of a family of 10 genes that encode different types of sodium channels, i.e. brain-type ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyme Disease
Lyme disease, also known as Lyme borreliosis, is a vector-borne disease caused by the ''Borrelia'' bacterium, which is spread by ticks in the genus ''Ixodes''. The most common sign of infection is an expanding red rash, known as erythema migrans (EM), which appears at the site of the tick bite about a week afterwards. The rash is typically neither itchy nor painful. Approximately 70–80% of infected people develop a rash. Early diagnosis can be difficult. Other early symptoms may include fever, headaches and tiredness. If untreated, symptoms may include loss of the ability to move one or both sides of the face, joint pains, severe headaches with neck stiffness or heart palpitations. Months to years later repeated episodes of joint pain and swelling may occur. Occasionally shooting pains or tingling in the arms and legs may develop. Despite appropriate treatment about 10 to 20% of those affected develop joint pains, memory problems and tiredness for at least six months. Lym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chagas Disease
Chagas disease, also known as American trypanosomiasis, is a tropical parasitic disease caused by ''Trypanosoma cruzi''. It is spread mostly by insects in the subfamily ''Triatominae'', known as "kissing bugs". The symptoms change over the course of the infection. In the early stage, symptoms are typically either not present or mild, and may include fever, swollen lymph nodes, headaches, or swelling at the site of the bite. After four to eight weeks, untreated individuals enter the chronic phase of disease, which in most cases does not result in further symptoms. Up to 45% of people with chronic infections develop heart disease 10–30 years after the initial illness, which can lead to heart failure. Digestive complications, including an enlarged esophagus or an enlarged colon, may also occur in up to 21% of people, and up to 10% of people may experience nerve damage. is commonly spread to humans and other mammals by the bite of a kissing bug. The disease may also be spr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheumatic Fever
Rheumatic fever (RF) is an inflammatory disease that can involve the heart, joints, skin, and brain. The disease typically develops two to four weeks after a streptococcal throat infection. Signs and symptoms include fever, multiple painful joints, involuntary muscle movements, and occasionally a characteristic non-itchy rash known as erythema marginatum. The heart is involved in about half of the cases. Damage to the heart valves, known as rheumatic heart disease (RHD), usually occurs after repeated attacks but can sometimes occur after one. The damaged valves may result in heart failure, atrial fibrillation and infection of the valves. Rheumatic fever may occur following an infection of the throat by the bacterium ''Streptococcus pyogenes''. If the infection is left untreated, rheumatic fever occurs in up to three percent of people. The underlying mechanism is believed to involve the production of antibodies against a person's own tissues. Due to their genetics, some peo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connective Tissue Disease
A connective tissue disease (collagenosis) is any disease that has the connective tissues of the body as a target of pathology. Connective tissue is any type of biological tissue with an extensive extracellular matrix that supports, binds together, and protects organs. These tissues form a framework, or matrix, for the body, and are composed of two major structural protein molecules: collagen and elastin. There are many different types of collagen protein in each of the body's tissues. Elastin has the capability of stretching and returning to its original length—like a spring or rubber band. Elastin is the major component of ligaments (tissues that attach bone to bone) and skin. In patients with connective tissue disease, it is common for collagen and elastin to become injured by inflammation (ICT). Many connective tissue diseases feature abnormal immune system activity with inflammation in tissues as a result of an immune system that is directed against one's own body tissues ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hereditary Haemochromatosis
Hereditary haemochromatosis type 1 (HFE-related Hemochromatosis) is a genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron stores. Humans, like most animals, have no means to excrete excess iron, with the exception of menstruation which, for the average woman, results in a loss of 3.2 mg of iron. Excess iron accumulates in tissues and organs, disrupting their normal function. The most susceptible organs include the liver, heart, pancreas, skin, joints, gonads, thyroid and pituitary gland; patients can present with cirrhosis, polyarthropathy, hypogonadism, heart failure, or diabetes.https://www.cdc.gov/genomics/disease/hemochromatosis.htm. Centers for Disease Control and Prevention There are 5 types of hereditary hemochromatosis: type 1, 2 (2A, 2B), 3, 4 and 5, all caused by mutated genes. Hereditary hemochromatosis is the most frequent, and unique related to the HFE gene. It is most com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amyloidosis
Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue. There are several non-specific and vague signs and symptoms associated with amyloidosis. These include fatigue, peripheral edema, weight loss, shortness of breath, palpitations, and Orthostatic hypotension, feeling faint with standing. In AL amyloidosis, specific indicators can include enlargement of the tongue and periorbital purpura. In wild-type ATTR amyloidosis, non-cardiac symptoms include: bilateral carpal tunnel syndrome, lumbar spinal stenosis, biceps tendon rupture, Small fiber peripheral neuropathy, small fiber neuropathy, and autonomic dysfunction. There are about 36 different types of amyloidosis, each due to a specific Proteopathy, protein misfolding. Within these 36 proteins, 19 are grouped into Organ-limited amyloidosis, localized forms, 14 are grouped as Systemic disease, systemic forms, and 3 proteins can identify as either. These proteins can become irre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoidosis
Sarcoidosis (also known as ''Besnier-Boeck-Schaumann disease'') is a disease involving abnormal collections of inflammatory cells that form lumps known as granulomata. The disease usually begins in the lungs, skin, or lymph nodes. Less commonly affected are the eyes, liver, heart, and brain. Any organ can be affected though. The signs and symptoms depend on the organ involved. Often, no, or only mild, symptoms are seen. When it affects the lungs, wheezing, coughing, shortness of breath, or chest pain may occur. Some may have Löfgren syndrome with fever, large lymph nodes, arthritis, and a rash known as erythema nodosum. The cause of sarcoidosis is unknown. Some believe it may be due to an immune reaction to a trigger such as an infection or chemicals in those who are genetically predisposed. Those with affected family members are at greater risk. Diagnosis is partly based on signs and symptoms, which may be supported by biopsy. Findings that make it likely include large lymph n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
