query: where does the electrical impulse of the heart originate

pos: Electrical conduction system of the heart Electrical conduction system of the heart The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node to cause contraction of the heart muscle. The pacemaking signal generated in the sinoatrial node travels through the right atrium to the atrioventricular node, along the Bundle of His and through bundle branches to cause contraction of the heart muscle. This signal stimulates contraction first of the right and left atrium, and then the right and left ventricles. This process allows blood to be pumped throughout the body. The conduction system consists of specialised heart muscle cells, and is

pos: Sinoatrial node therefore cause ischaemia and cell death in the SA node. This can disrupt the electrical pacemaker function of the SA node, and can result in sick sinus syndrome. If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical conduction system, a group of cells further down the heart will become its pacemaker. The sinoatrial node was first discovered by a young medical student, Martin Flack, in the heart of a mole, whilst his mentor, Sir Arthur Keith, was on a bicycle ride with his wife. They made

pos: Myocardial infarction complications phenomenon may cause rapid heart rates (ventricular tachycardia and even ventricular fibrillation), and ischemia in the electrical conduction system of the heart may cause a complete heart block (when the impulse from the sinoatrial node, the normal cardiac pacemaker, does not reach the heart chambers). As a reaction to the damage of the heart muscle, inflammatory cells are attracted. The inflammation may reach out and affect the heart sac. This is called pericarditis. In Dressler's syndrome, this occurs several weeks after the initial event. If pericarditis were to persist, pleural effusion may also occur which could in turn lead to

pos: Bundle branch block restore an optimal electrical supply to the heart muscle. Bundle branch block A bundle branch block is a defect of the bundle branches or fascicles in the electrical conduction system of the heart. The heart's electrical activity begins in the sinoatrial node (the heart's natural pacemaker), which is situated on the upper right atrium. The impulse travels next through the left and right atria and summates at the atrioventricular node. From the AV node the electrical impulse travels down the bundle of His and divides into the right and left bundle branches. The right bundle branch contains one fascicle. The

pos: Accelerated idioventricular rhythm injury. AIVR is generally considered to be a benign abnormal heart rhythm. It is typically temporary and does not require treatment. In the human heart the sinoatrial node is located at the top of the right atrium. The sinoatrial node is the first area of the heart to depolarize and to generate the action potential that leads to depolarization of the rest of the myocardium. Sinoatrial depolarization and subsequent propagation of the electrical impulse suppress the action of the lower natural pacemakers of the heart, which have slower intrinsic rates. The accelerated idioventricular rhythm occurs when depolarization rate of a

pos: Sinoatrial block Sinoatrial block A sinoatrial 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 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

pos: Electrical conduction system of the heart has a regular rate of 40 to 60 bpm. These "junctional" rhythms are characterized by a missing or inverted P-Wave. If both the SA node and the AV junction fail to initialize the electrical impulse, the ventricles can fire the electrical impulses themselves at a rate of 20 to 40 bpm and will have a QRS complex of greater than 120 ms. In the event of arrhythmia, a pacemaker may be surgically inserted into the conduction system. Electrical conduction system of the heart The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node to cause

pos: Bundle branch block Bundle branch block A bundle branch block is a defect of the bundle branches or fascicles in the electrical conduction system of the heart. The heart's electrical activity begins in the sinoatrial node (the heart's natural pacemaker), which is situated on the upper right atrium. The impulse travels next through the left and right atria and summates at the atrioventricular node. From the AV node the electrical impulse travels down the bundle of His and divides into the right and left bundle branches. The right bundle branch contains one fascicle. The left bundle branch subdivides into two fascicles: the left

pos: Heart arrhythmia different timing than usual and can be responsible for poorly coordinated contraction. Conditions that increase automaticity include sympathetic nervous system stimulation and hypoxia. The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue. Re-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping. Every cardiac cell is able to transmit impulses of excitation in

pos: Sinoatrial node Sinoatrial node The sinoatrial node (SA node), also known as sinus node, is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below for more details), that travels through the heart via the electrical conduction system (see figure 1) causing it to contract. In a healthy heart, the SA node continuously produces action potential, setting the rhythm of the heart and so is known as the heart's natural pacemaker. The rate of action potential production (and therefore the heart rate)

pos: Atrial tachycardia Atrial tachycardia Atrial tachycardia is a type of heart rhythm problem in which the heart's electrical impulse comes from an ectopic pacemaker (that is, an abnormally located cardiac pacemaker) in the upper chambers (atria) of the heart, rather than from the sinoatrial node, the normal origin of the heart's electrical activity. Atrial tachycardias can exhibit very regular (consistent) heart rates ranging typically from 140 to 220 beats per minute. As with any other form of tachycardia (rapid heart beat), the underlying mechanism can be either the rapid discharge of an abnormal focus, the presence of a ring of cardiac tissue

pos: Atrial tachycardia label subsets). The codification of the terms "first detected", "paroxysmal", "persistent", and "permanent" in the classification of atrial fibrillation should be compared for reference. Atrial tachycardia Atrial tachycardia is a type of heart rhythm problem in which the heart's electrical impulse comes from an ectopic pacemaker (that is, an abnormally located cardiac pacemaker) in the upper chambers (atria) of the heart, rather than from the sinoatrial node, the normal origin of the heart's electrical activity. Atrial tachycardias can exhibit very regular (consistent) heart rates ranging typically from 140 to 220 beats per minute. As with any other form of tachycardia

pos: Sinoatrial node the discovery in a makeshift laboratory set up in a picturesque farmhouse in Kent, England, called Mann's Place. Their discovery was published in 1907. Sinoatrial node The sinoatrial node (SA node), also known as sinus node, is a group of cells located in the wall of the right atrium of the heart. These cells have the ability to spontaneously produce an electrical impulse (action potential; see below for more details), that travels through the heart via the electrical conduction system (see figure 1) causing it to contract. In a healthy heart, the SA node continuously produces action potential, setting the

pos: Third-degree atrioventricular block may also include medicines to control blood pressure and atrial fibrillation, as well as lifestyle and dietary changes to reduce risk factors associated with heart attack and stroke. The prognosis of patients with complete heart block is generally poor without therapy. Patients with 1st and 2nd degree heart block are usually asymptomatic. Third-degree atrioventricular block Third-degree atrioventricular block (AV block), also known as complete heart block, is a medical condition in which the nerve impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles. Because the impulse is blocked, an

pos: Third-degree atrioventricular block Third-degree atrioventricular block Third-degree atrioventricular block (AV block), also known as complete heart block, is a medical condition in which the nerve impulse generated in the sinoatrial node (SA node) in the atrium of the heart does not propagate to the ventricles. Because the impulse is blocked, an accessory pacemaker in the lower chambers will typically activate the ventricles. This is known as an "escape rhythm". Since this accessory pacemaker also activates independently of the impulse generated at the SA node, two independent rhythms can be noted on the electrocardiogram (ECG). People with third-degree AV block typically experience severe bradycardia

pos: Ectopic beat Ectopic beat Ectopic beat (or cardiac ectopy) is a disturbance of the cardiac rhythm frequently related to the electrical conduction system of the heart, in which beats arise from fibers or group of fibers outside the region in the heart muscle ordinarily responsible for impulse formation ("i.e.", the sinoatrial node). An ectopic beat can be further classified as either a premature ventricular contraction, or a premature atrial contraction. Some patients describe this experience as a 'flip' or a 'jolt' in the chest, or a 'heart hiccups', while others report dropped or missed beats. Ectopic beats are more common during periods

pos: Atrial fibrillation the atrial tissue, favouring the re-entry. There is a relationship between risk factors such as obesity and hypertension, with the appearance of diseases such as diabetes mellitus and sleep apnea-hypopnea syndrome, specifically, obstructive sleep apnea (OSA). These diseases are associated with an increased risk of AF due to their remodelling effects on the atrial substrate. The normal electrical conduction system of the heart allows the impulse that is generated by the sinoatrial node (SA node) of the heart to be propagated to and stimulate the myocardium (muscular layer of the heart). When the myocardium is stimulated, it contracts. It is

pos: Purkinje fibers the nucleus causes Purkinje fibers to appear, on a slide, lighter and larger than their neighbors, arranged along the longitudinal direction (parallel to the cardiac vector). They are often binucleated cells. Heart rate is governed by many influences from the autonomic nervous system. The Purkinje fibres do not have any known role in setting heart rate unless the SA node is compromised. They are influenced by electrical discharge from the sinoatrial node. During the ventricular contraction portion of the cardiac cycle, the Purkinje fibres carry the contraction impulse from both the left and right bundle branch to the myocardium of

pos: Poincaré plot the normal person is triggered by an electrical impulse that originates the sinoatrial node. The ECG normally consists of a series of waves, labeled the P, Q, R, S and T waves. The P wave represents depolarization of the atria, Q-R-S series of waves the depolarization of the ventricles, and T wave the repolarization of the ventricles. The interval between two successive R waves (the RR interval) is a measure of the heart rate. The heart rate normally varies slightly: during a deep breath, it speeds up and during a deep exhalation, it slows down. (The RR interval will shorten

pos: Sinoatrial arrest an electrocardiogram (ECG) as a brief period of irregular length with no electrical activity before either the sinoatrial node resumes normal pacing, or another pacemaker begins pacing. If a pacemaker other than the sinoatrial node is pacing the heart, this condition is known as an escape rhythm. If no other pacemaker begins pacing during an episode of sinus arrest it becomes a cardiac arrest. This condition is sometimes confused with sinoatrial block, a condition in which the pacing impulse is generated, but fails to conduct through the myocardium. Differential diagnosis of the two conditions is possible by examining the exact

neg: Heart arrhythmia years, bases for the classification of arrhythmias are still being discussed. Congenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected with this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. Wolff–Parkinson–White syndrome is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right ventricular outflow tract tachycardia is

neg: Neural Impulse Actuator Neural Impulse Actuator The Neural Impulse Actuator (NIA) is a brain–computer interface (BCI) device developed by OCZ Technology. BCI devices attempt to move away from the classic input devices like keyboard and mouse and instead read electrical activity from the head, preferably the EEG. The name Neural Impulse Actuator implies that the signals originate from some neuronal activity; however, what is actually captured is a mixture of muscle, skin and nerve activity including sympathetic and parasympathetic components that have to be summarized as biopotentials rather than pure neural signals. As of May 27, 2011, the OCZ website says that the

neg: Heart block contract. In SA node suppression, on the other hand, the SA node doesn't generate an electrical impulse because it is reset by the electrical impulse that enters the SA node. There are three basic types of AV nodal block: Infra-Hisian block is that of the distal conduction system. Types of infra-Hisian block include: Of these types of infra-Hisian block, Mobitz II heart block is considered most important because of the possible progression to complete heart block. Heart block Heart block is a disorder in the heart's rhythm due to a fault in the natural pacemaker. This is caused by an

neg: Premature atrial contraction other underlying structural heart problems, PACs can trigger a more serious arrhythmia such as atrial flutter or atrial fibrillation. In otherwise healthy people, PACs usually disappear with adolescence. A supraventricular extrasystole (SVES) is an extrasystole or premature electrical impulse in the heart, generated above the level of the ventricle. This can be either a premature atrial contraction or a premature impulse from the atrioventricular node. SVES should be viewed in contrast to a premature ventricular contraction which has a ventricular origin and the associated QRS change. Instead of the electrical impulse beginning in the sinoatrial (SA) node and propagating to

neg: Rhythm interpretation base line on a rhythm strip make up the PQRST sequence. There are a few key intervals that must be measured for proper analysis of a heart rhythm, The PR interval is the interval between the end of the P wave and the beginning of the Q wave. This represents the conduction of the atria of the heart, the speed at which they are able to conduct an electrical impulse. The QRS complex represents the conduction of the ventricles of the heart, the speed at which they are able to conduct an electrical impulse. The interval between each R wave

neg: Bathmotropic Bathmotropic While bathmotropic, as used herein, has been defined as pertaining to modification of the "excitability" of the heart, it can also refer to modification of the "irritability" of heart muscle, and the two terms are frequently used interchangeably. The term "bathmotropic" is derived from the Ancient Greek word "βαθμός" ("bathmós"), meaning "step" or "threshold". In 1897 Engelmann introduced four Greek terms to describe key physiological properties of the heart: inotropy, the ability to contract; chronotropy, the ability to initiate an electrical impulse; dromotropy, the ability to conduct an electrical impulse; and bathmotropy, the ability to respond to direct mechanical

neg: Heart block path of the electrical signals, the places where conduction can be blocked give rise to different kinds of heart blocks: SA and AV node blocks are each divided into three degrees, with second degree blocks being divided into two types (written either "type I or II" or "type 1 or 2"). In an SA block, the electrical impulse is delayed or blocked on the way to the atria, thus delaying atrial depolarization. By contrast, an AV block occurs in the AV node and delays ventricular depolarization. The term "Wenckebach block" is also used for some heart blocks, and can refer

neg: Parasternal heave Parasternal heave A parasternal heave (or lift) is a precordial impulse that may be felt (palpated) in patients with cardiac or respiratory disease. Precordial impulses are visible or palpable pulsations of the chest wall, which originate on the heart or the great vessels. A parasternal impulse may be felt when the heel of the hand is rested just to the left of the sternum with the fingers lifted slightly off the chest. Normally no impulse or a slight inward impulse is felt. The heel of the hand is lifted off the chest wall with each systole. Palpation with the fingers

neg: Pilsicainide in the treatment of atrial fibrillation. Atrial fibrillation is the most common type of arrhythmia(14). It may result from various heart abnormalities or may occur spontaneously in a seemingly healthy individual(15). Atrial fibrillation is characterized by rapid, disorganized electrical impulses in the atria resulting in depolarization of only a small group of myocardial cells. This prevents the atria from undergoing coordinated contraction, instead resulting in small fibrillations of the heart muscle. Re-entry occurs when an impulse does not die after activating the heart but instead returns to the atria and causes re-excitation(16). Simultaneous re-entry of multiple impulses with short wavelengths

neg: Cardiac physiology toward the atrioventricular septum and the base of the heart. The Purkinje fibers have a fast inherent conduction rate, and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms. Since the electrical stimulus begins at the apex, the contraction also begins at the apex and travels toward the base of the heart, similar to squeezing a tube of toothpaste from the bottom. This allows the blood to be pumped out of the ventricles and into the aorta and pulmonary trunk. The total time elapsed from the initiation of the impulse in the SA node until

neg: Electrical conduction system of the heart the SA node's pacemaker activity. In order to maximize efficiency of contractions and cardiac output, the conduction system of the heart has: An electrocardiogram is a recording of the electrical activity of the heart. Under normal conditions, electrical activity is spontaneously generated by the SA node, the cardiac pacemaker. This electrical impulse is propagated throughout the right atrium, and through Bachmann's bundle to the left atrium, stimulating the myocardium of the atria to contract. The conduction of the electrical impulses throughout the atria is seen on the ECG as the P wave. As the electrical activity is spreading throughout the

neg: Atrial fibrillation In AF, there is no regularity of this kind, except at the sources where the local activation rate can exceed 500 bpm. Although the electrical impulses of AF occur at a high rate, most of them do not result in a heart beat. A heart beat results when an electrical impulse from the atria passes through the atrioventricular (AV) node to the ventricles and causes them to contract. During AF, if all of the impulses from the atria passed through the AV node, there would be severe ventricular tachycardia, resulting in a severe reduction of cardiac output. This dangerous situation

neg: Fusion beat the pseudofusion beat wherein the pacemaker impulse does not affect the complex of the natural beat of the heart. Pseudofusion beats are normal. Rare or isolated fusion beats caused by pacemakers are normal as well, but if they occur too frequently may reduce cardiac output and so can require adjustment of the pacemaker. Fusion beat A fusion beat occurs when electrical impulses from different sources act upon the same region of the heart at the same time. If it acts upon the ventricular chambers it is called a ventricular fusion beat, whereas colliding currents in the atrial chambers produce atrial

neg: Atrial flutter a premature electrical impulse arising in the atria, atrial flutter is propagated due to differences in refractory periods of atrial tissue. This creates electrical activity that moves in a localized self-perpetuating loop, which usually lasts about 200 milliseconds for the complete circuit. For each cycle around the loop, an electric impulse results and propagates through the atria. The impact and symptoms of atrial flutter depend on the heart rate of the affected person. Heart rate is a measure of the ventricular rather than atrial activity. Impulses from the atria are conducted to the ventricles through the atrio-ventricular node (AV node).

neg: Cardiac physiology capable of generating its own electrical impulse followed by contraction. When two independently beating embryonic cardiac muscle cells are placed together, the cell with the higher inherent rate sets the pace, and the impulse spreads from the faster to the slower cell to trigger a contraction. As more cells are joined together, the fastest cell continues to assume control of the rate. A fully developed adult heart maintains the capability of generating its own electrical impulse, triggered by the fastest cells, as part of the cardiac conduction system. The components of the cardiac conduction system include the atrial and ventricular

neg: Heart arrhythmia needs, this manifests as a lower blood pressure and may cause lightheadedness or dizziness, or syncope (fainting). Some types of arrhythmia result in cardiac arrest, or sudden death. Medical assessment of the abnormality using an electrocardiogram is one way to diagnose and assess the risk of any given arrhythmia. Each heart beat originates as an electrical impulse from a small area of tissue in the right atrium of the heart called the sinus node or Sino-atrial node or SA node. The impulse initially causes both atria to contract, then activates the atrioventricular (or AV) node, which is normally the only

neg: Electrical conduction system of the heart of 40 to 60bpm. These "junctional" rhythms are characterized by a missing or inverted P wave. If both the SA node and the AV junction fail to initialize the electrical impulse, the ventricles can fire the electrical impulses themselves at a rate of 20 to 40bpm and will have a QRS complex of greater than 120 ms. This is necessary for the heart to be in good function. An 'arrhythmia' refers to an abnormal rhythm or speed of rhythm of the heartbeat. An abnormal rhythm or speed is defined as one which is not physiological. A resting heart that beats

neg: Cardiac pacemaker out of the cell and pumping (exchanging) potassium into the cell. Restoring these ion concentrations is vital because it enables the cell to reset itself and enables it to repeat the process of spontaneous depolarization leading to activation of an action potential. If the SA node does not function, or the impulse generated in the SA node is blocked before it travels down the electrical conduction system, a group of cells further down the heart will become its pacemaker. This center is typically represented by cells inside the atrioventricular node (AV node), which is an area between the atria and

neg: Demand pacemaker reinitiate influencing the electric activity in the heart when the pathologic event happens again. A "ventricular-demand pacemaker" produces a narrow vertical spike on the ECG, just before a wide QRS. The spike of an "atrial-demand pacemaker" appears just before the P wave. Comparably, a Triggered Pacemaker is activated immediately after an electrical activity is commenced in the heart tissue by itself. A "ventricular triggered pacemaker" produces the impulse just after a pulse is created in the ventricular tissue and it appears as a simultaneous spike with QRS. An "atrial triggered pacemaker" is the mode in which an impulse is produced

neg: Atrioventricular node This property is important because loss of the conduction system before the AV node should still result in pacing of the ventricles by the — slower — pacemaking ability of the AV node. Atrioventricular node The atrioventricular node, or AV node is a part of the electrical conduction system of the heart that coordinates the top of the heart. It electrically connects the atria and ventricles. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles. The AV

neg: Atrioventricular node Atrioventricular node The atrioventricular node, or AV node is a part of the electrical conduction system of the heart that coordinates the top of the heart. It electrically connects the atria and ventricles. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, which conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm). The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, which conducts the

neg: Pulseless electrical activity Pulseless electrical activity Pulseless electrical activity (PEA), also known as electromechanical dissociation, refers to cardiac arrest in which the electrocardiogram shows a heart rhythm that should produce a pulse, but does not. Pulseless electrical activity is found initially in about 55% of people in cardiac arrest. Under normal circumstances, electrical activation of muscle cells precedes mechanical contraction of the heart (known as "electromechanical coupling"). In PEA, there is electrical activity, but the heart either does not contract or there are other reasons this results in an insufficient cardiac output to generate a pulse and supply blood to the organs. While

neg: Heart arrhythmia electrical connection between the atria and the ventricles (main pumping chambers). The impulse then spreads through both ventricles via the Bundle of His and the Purkinje fibres causing a synchronised contraction of the heart muscle and, thus, the pulse. In adults the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered as normal. The term sinus arrhythmia refers to a normal phenomenon of alternating mild acceleration and slowing of

neg: Heart secondary to old age, but may also be caused by infection of the heart valves (endocarditis). In some parts of the world rheumatic heart disease is a major cause of valvular heart disease, typically leading to mitral or aortic stenosis and caused by the body's immune system reacting to a streptococcal throat infection. While in the healthy heart, waves of electrical impulses originate in the sinus node before spreading to the rest of the atria, the atrioventricular node, and finally the ventricles (referred to as a normal sinus rhythm), this normal rhythm can be disrupted. Abnormal heart rhythms or arrhythmias

neg: Otto Loewi physiological responses could be caused by applying an electrical impulse, which suggested that electrical transmission may be the only mode of endogenous signaling. In the early 20th century the controversy of whether cells used chemical or electrical transmission divided even the most prominent scientists. Loewi's famous experiment, published in 1921, largely answered this question. According to Loewi, the idea for his key experiment came to him in his sleep, causing him to go directly to the laboratory in the middle of the night. He dissected out of frogs two beating hearts: one with the vagus nerve which controls heart rate

neg: Cameron Health incrementally as various revenue milestones were achieved. , Boston Scientific still markets the S-ICD system. Every ICD is designed to detect heart rhythms consistent with a catastrophic failure of the body's natural regulation of the heartbeat, which, untreated, could result in death. When an ICD detects a serious arrhythmia, it issues an electrical impulse to the heart muscle, of a magnitude sufficient to cause the heart to revert to a normal rhythm. ICDs with transvenous leads administer this shock to the interior of the heart muscle; the Cameron Health device generated a more powerful shock which can be effective from

neg: Heart arrhythmia the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during meditation breathing exercises that involve deep inhaling and breath holding patterns. A slow rhythm (less than 60 beats/min) is labelled bradycardia. This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block

neg: Ventricular tachycardia and turn into ventricular fibrillation. Ventricular tachycardia can occur due to coronary heart disease, aortic stenosis, cardiomyopathy, electrolyte problems (e.g., low blood levels of magnesium or potassium), inherited channelopathies (e.g., long-QT syndrome), catecholaminergic polymorphic ventricular tachycardia, arrhythmogenic right ventricular dysplasia, or a heart attack. The morphology of the tachycardia depends on its cause and the origin of the re-entry electrical circuit in the heart. In monomorphic ventricular tachycardia, the shape of each heart beat on the ECG looks the same because the impulse is either being generated from increased automaticity of a single point in either the left or the

neg: Repetitive Electrical Impulse Noise is emitting a radio frequency, which causes electrical impulses along the telephone line. The cause of the REIN can be traced by using a directional radio frequency analyzer, as the source of the REIN is often broadcasting interference on 612 kHz (AM). Repetitive Electrical Impulse Noise Repetitive Electrical Impulse Noise (REIN) is a term applied to some interference found on problematic DSL internet connections. The interference can be detected as electrical impulses on the physical telephone line on which the internet connection operates. REIN is particularly problematic as it can cause DSL modems to lose synchronisation and drop connection. REIN

neg: Repetitive Electrical Impulse Noise Repetitive Electrical Impulse Noise Repetitive Electrical Impulse Noise (REIN) is a term applied to some interference found on problematic DSL internet connections. The interference can be detected as electrical impulses on the physical telephone line on which the internet connection operates. REIN is particularly problematic as it can cause DSL modems to lose synchronisation and drop connection. REIN causes interference which in turn causes a DSL modem to mount up CRC errors. This eventually causes DSL synchronisation to drop. REIN is often caused by faulty electrical equipment which is in the proximity of the broadband telephone line. Usually the equipment

neg: Stannius ligature Stannius ligature Stannius Ligature is an experimental procedure to illustrate impulse conduction in frog heart. A ligature placed either around the junction between the sinus venosus and atrium of the frog or turtle heart (first stannius ligature) or around the atrioventricular junction (second stannius ligature); demonstrates that the cardiac impulse is conducted from sinus venosus to atria to ventricle, but that successive chambers possess automaticity since each may continue to beat, but the atria now have a slower rate than the sinus venosus, and the ventricle either does not contract or beats at a slower rate than the atria. In

neg: Flecainide for a beating heart and to increase blood flow to the liver. Flecainide has a very high affinity for lung tissue and is associated with drug-induced interstitial lung disease. Flecainide works by blocking the Nav1.5 sodium channel in the heart, slowing the upstroke of the cardiac action potential. This thereby slows conduction of the electrical impulse within the heart, i.e. it "reduces excitability". The greatest effect is on the His-Purkinje system and ventricular myocardium. The effect of flecainide on the ventricular myocardium causes decreased contractility of the muscle, which leads to a decrease in the ejection fraction. The effect of

neg: Bundle of His 0.03–0.04 seconds for the impulse to travel from the bundle of His to the ventricular muscle. Disorders affecting the cardiomyocytes that make up the electrical conduction system of the heart are called heart blocks. Heart blocks are separated into different categories based on the location of the cellular damage. Damage to any of the conducting cells in or below the bundle of His are collectively referred to as "infra-Hisian blocks". To be specific, blocks that occur in the right or left bundle branches are called "bundle branch blocks", and those that occur in either the left anterior or the left

neg: Cardiac excitation-contraction coupling Cardiac excitation-contraction coupling Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction of muscles in the heart. This process is of vital importance as it allows for the heart to beat in a controlled manner, without the need for conscious input. EC coupling results in the sequential contraction of the heart muscles that allows blood to be pumped, first to the lungs (pulmonary circulation) and then around the rest of the body (systemic circulation) at a rate between 60 and 100 beats every minute, when the

neg: Lev's disease Lev's disease Lev's disease (or Lenegre-Lev syndrome) is an acquired complete heart block due to idiopathic fibrosis and calcification of the electrical conduction system of the heart. Lev's disease is most commonly seen in the elderly, and is often described as senile degeneration of the conduction system. One form has been associated with SCN5A. Stokes-Adams attacks can be precipitated by this condition. These involve a temporary loss of consciousness resulting from marked slowing of the heart when the atrial impulse is no longer conducted to the ventricles. This should not be confused with the catastrophic loss of heartbeat seen with

neg: First-degree atrioventricular block to complete heart block. First-degree atrioventricular block First-degree atrioventricular block (AV block), or PR prolongation, is a disease of the electrical conduction system of the heart in which the PR interval is lengthened beyond 0.20 seconds. In first-degree AV block, the impulse conducting from atria to ventricles through the atrioventricular node (AV node) is delayed and travels slower than normal. It has a prevalence in the normal (young adult) population of 0.65-1.1% and the incidence is 0.13 per 1000 persons. The most common causes of first-degree heart block are an AV nodal disease, enhanced vagal tone (for example in athletes),

neg: Multifocal atrial tachycardia with a narrow therapeutic index commonly used to treat COPD. Theophylline can cause a number of different abnormal heart rhythms when in excess, and thus further predisposes COPD patients to MAT. Theophylline toxicity often occurs following acute or chronic overtreatment or factors lowering its clearance from the body. The P-waves and P–R intervals are variable due to a phenomenon called wandering atrial pacemaker (WAP). The electrical impulse is generated at a different focus within the atria of the heart each time. WAP is positive once the heart generates at least three different P-wave formations from the same ECG lead. Then,

neg: Bundle branch block for ventricular depolarization. Since the electrical impulse can no longer use the preferred pathway across the bundle branch, it may move instead through muscle fibers in a way that both slows the electrical movement and changes the directional propagation of the impulses. As a result, there is a loss of ventricular synchrony, ventricular depolarization is prolonged, and there may be a corresponding drop in cardiac output. When heart failure is present, a specialized pacemaker may be used to resynchronize the ventricles. In theory a pacemaker like this will shorten the QRS interval, thus bringing the timing of contraction of the

neg: Premature junctional contraction Premature junctional contraction Premature junctional contractions (PJCs), also called atrioventricular junctional premature complexes or junctional extrasystole, are premature cardiac electrical impulses originating from the atrioventricular node of the heart or "junction". This area is not the normal but only a secondary source of cardiac electrical impulse formation. These premature beats can be found occasionally in healthy people and more commonly in some pathologic conditions, typically in the case of drug cardiotoxicity, electrolyte imbalance, mitral valve surgery, and cold water immersion. If more than two such beats are seen, then the condition is termed junctional rhythm. On the surface ECG, premature

neg: Premature junctional contraction junctional contractions will appear as a normally shaped ventricular complex or QRS complex, not preceded by any atrial complex or P wave or preceded by an abnormal P wave with a shorter PR interval. Rarely, the abnormal P wave can follow the QRS. Premature junctional contraction Premature junctional contractions (PJCs), also called atrioventricular junctional premature complexes or junctional extrasystole, are premature cardiac electrical impulses originating from the atrioventricular node of the heart or "junction". This area is not the normal but only a secondary source of cardiac electrical impulse formation. These premature beats can be found occasionally in healthy people

neg: First-party leads face interaction between an in-the-market consumer and a sales person or expert in that field. Sometimes these visitors are the result of targeted or un-targeted advertisements that may lead to impulse buys that fulfill desires for luxury or non-essential items. These ads might show up as banner ads, pay per click ads, social network ads and other revenue generators through ad networks and affiliate marketing. First-party leads differ from third-party leads based on where they originate. If they originate from the direct efforts of the website owner, then they are a first-party lead. i.e. When someone visits the website of

neg: Electrical treeing electrical field and water. Water trees may eventually grow to the point where they bridge the outer ground layer to the center high voltage conductor, at which point the stress redistributes across the insulation. Water trees are not generally a reliability concern unless they are able to initiate an electrical tree. Another type of tree-like structure can form with or without the presence of water is called an electrical tree. It also forms within a polyethylene dielectric (as well as many other solid dielectrics). Electrical trees also originate where bulk or surface stress enhancements initiate dielectric breakdown in a small

neg: Atrioventricular reentrant tachycardia is likely to be asymptomatic, however, the ECG would demonstrate the classic delta wave in Wolff–Parkinson–White syndrome. Two distinct pathways are involved: the normal atrioventricular conduction system, and an accessory pathway. During AVRT, the electrical signal passes in the normal manner from the AV node into the ventricles. Then, the electrical impulse pathologically passes back into the atria via the accessory pathway, causing atrial contraction, and returns to the AV node to complete the reentrant circuit (see figure). Once initiated, the cycle may continue causing the heart to beat faster than usual. Initiation of AVRT may be through a premature

neg: Bundle of His electrical conduction system of the heart, as it transmits impulses from the atrioventricular node, located at the inferior end of the interatrial septum, to the ventricles of the heart. The bundle of His branches into the left and the right bundle branches, which run along the interventricular septum. The left bundle branch further divides into the left anterior and the left posterior fascicles. These bundles and fascicles give rise to thin filaments known as Purkinje fibers. These fibers distribute the impulse to the ventricular muscle. The ventricular conduction system comprises the bundle branches and the Purkinje networks. It takes about

neg: Artificial cardiac pacemaker involved and their basic operating mechanism: The pacemaker generator is a hermetically sealed device containing a power source, usually a lithium battery, a sensing amplifier which processes the electrical manifestation of naturally occurring heart beats as sensed by the heart electrodes, the computer logic for the pacemaker and the output circuitry which delivers the pacing impulse to the electrodes. Most commonly, the generator is placed below the subcutaneous fat of the chest wall, above the muscles and bones of the chest. However, the placement may vary on a case by case basis. The outer casing of pacemakers is so designed

neg: Bradycardia from excessive vagal tone on the SA node. Pathological causes include sinus bradycardia, sinus arrest, sinus exit block, or AV block. A ventricular bradycardia, also known as ventricular escape rhythm or idioventricular rhythm, is a heart rate of less than 50 BPM. This is a safety mechanism when a lack of electrical impulse or stimuli from the atrium occurs. Impulses originating within or below the bundle of His in the atrioventricular node will produce a wide QRS complex with heart rates between 20 and 40 BPM. Those above the bundle of His, also known as junctional, will typically range between

neg: Common ostrich node connects the atrial and ventricular chambers. It functions to carry the electrical impulse from the atria to the ventricle. Upon view, the myocardial cells are observed to have large densely packed chromosomes within the nucleus. The coronary arteries start in the right and left aortic sinus and provide blood to the heart muscle in a similar fashion to most other vertebrates. Other domestic birds capable of flight have three or more coronary arteries that supply blood to the heart muscle. The blood supply by the coronary arteries are fashioned starting as a large branch over the surface of the

neg: Heart block issues elsewhere in the heart, and therefore SA blocks are - despite their lower level of life-threatening risk - still "the most common indication for pacemaker implantation in the US". Types of SA nodal blocks include: In addition to the above blocks, the SA node can be suppressed by any other arrhythmia that reaches it. This includes retrograde conduction from the ventricles, ectopic atrial beats, atrial fibrillation, and atrial flutter. The difference between SA node block and SA node suppression is that in SA node block an electrical impulse is generated by the SA node that doesn't make the atria

neg: Catheter ablation an increased chance of success with an ablation since their heart has not undergone atrial remodeling yet. Risks of catheter ablation for atrial fibrillation include, but are not limited to: stroke, esophageal injury, pulmonary vein stenosis, and death. Catheter ablation involves advancing several flexible catheters into the patient's blood vessels, usually either in the femoral vein, internal jugular vein, or subclavian vein. The catheters are then advanced towards the heart. Electrical impulses are then used to induce the arrhythmia and local heating or freezing is used to ablate (destroy) the abnormal tissue that is causing it. Originally, a DC impulse

neg: Electrocardiography electrical activity from within the heart. Some catheters contain several electrodes and can record the propagation of electrical activity. Interpretation of the ECG is fundamentally about understanding the electrical conduction system of the heart. Normal conduction starts and propagates in a predictable pattern, and deviation from this pattern can be a normal variation or be pathological. An ECG does not equate with mechanical pumping activity of the heart, for example, pulseless electrical activity produces an ECG that should pump blood but no pulses are felt (and constitutes a medical emergency and CPR should be performed). Ventricular fibrillation produces an ECG

neg: Plugboard was connected to an electrical power source and an electrical pulse, an "impulse" in IBM terminology, would be generated. Each brush was connected to an individual hub on the control panel, from which it could be wired to another hub, as needed. The action caused by an impulse on a wire depended on when in the cycle it occurred, a simple form of time division multiplexing. Thus an impulse that occurred during 7-time on a wire connected to the column 26 punch magnet would punch a hole in row 7 of column 26. An impulse on the same wire that

neg: Artificial cardiac pacemaker pacing" (ATP). ATP is only effective if the underlying rhythm is ventricular tachycardia, and is never effective if the rhythm is ventricular fibrillation. In 1889, John Alexander MacWilliam reported in the "British Medical Journal" (BMJ) of his experiments in which application of an electrical impulse to the human heart in asystole caused a ventricular contraction and that a heart rhythm of 60–70 beats per minute could be evoked by impulses applied at spacings equal to 60–70/minute. In 1926, Mark C Lidwill of the Royal Prince Alfred Hospital of Sydney, supported by physicist Edgar H. Booth of the University of Sydney,

neg: First-degree atrioventricular block First-degree atrioventricular block First-degree atrioventricular block (AV block), or PR prolongation, is a disease of the electrical conduction system of the heart in which the PR interval is lengthened beyond 0.20 seconds. In first-degree AV block, the impulse conducting from atria to ventricles through the atrioventricular node (AV node) is delayed and travels slower than normal. It has a prevalence in the normal (young adult) population of 0.65-1.1% and the incidence is 0.13 per 1000 persons. The most common causes of first-degree heart block are an AV nodal disease, enhanced vagal tone (for example in athletes), myocarditis, acute myocardial infarction

neg: Short QT syndrome the dispersion of repolarisation, occurs because the action potential shortening seen in this condition occurs to a greater extent in some layers of the heart wall than in others. This means that at certain points in the cardiac cycle, some layers of the heart wall will have fully repolarised, and are therefore ready to contract again, while other regions are only partially repolarised and therefore are still within their refractory period and not yet able to be re-excited. If a triggering impulse arrives at this critical point in the cardiac cycle, the wavefront of electrical activation will conduct in some

neg: First-degree atrioventricular block (especially acute inferior MI), electrolyte disturbances and medication. The medications that most commonly cause first-degree heart block are those that increase the refractory time of the AV node, thereby slowing AV conduction. These include calcium channel blockers, beta-blockers, cardiac glycosides, and anything that increases cholinergic activity such as cholinesterase inhibitors. In normal individuals, the AV node slows the conduction of electrical impulse through the heart. This is manifest on a surface electrocardiogram (ECG) as the PR interval. The normal PR interval is from 120 ms to 200 ms in length. This is measured from the initial deflection of the P

neg: Cardiac excitation-contraction coupling a neurotransmitter called acetylcholine (ACh) which binds to specific receptor (M2 muscarinic receptor) on the sarcolemma of both SAN cells and ventricular cells. This again activates a G-protein. However this G-protein works by inhibiting, the cAMP pathway, therefore, preventing the sympathetic nervous system from increasing heart rate. As well as this, in the SAN, the G-protein activates specific potassium channel, that opposes action potential initiation (see SAN for more details), thus slowing heart rate. Cardiac excitation-contraction coupling Cardiac excitation-contraction coupling (Cardiac EC coupling) describes the series of events, from the production of an electrical impulse (action potential) to the contraction

neg: Electrical treeing Electrical treeing In electrical engineering, treeing is an electrical pre-breakdown phenomenon in solid insulation. It is a damaging process due to partial discharges and progresses through the stressed dielectric insulation, in a path resembling the branches of a tree. Treeing of solid high-voltage cable insulation is a common breakdown mechanism and source of electrical faults in underground power cables. Electrical treeing first occurs and propagates when a dry dielectric material is subjected to high and divergent electrical field stress over a long period of time. Electrical treeing is observed to originate at points where impurities, gas voids, mechanical defects, or

neg: Heart development cells start to form creating the bundle of His that sends a branch to the right ventricle and one to the left ventricle. Most conduction pathways originate from the cardiogenic mesoderm but the sinus node may be derived from the neural crest. The human embryonic heart begins beating approximately 21 days after fertilization, or five weeks after the last normal menstrual period (LMP), which is the date normally used to date pregnancy in the medical community. The electrical depolarizations that trigger cardiac myocytes to contract arise spontaneously within the myocyte itself. The heartbeat is initiated in the pacemaker regions and

neg: Heart arrhythmia caused by re-entry. The method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery. In the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011. A number of physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop a number of arrhythmias that originate

neg: Heart sounds rhythms in which atrial contraction does not precede ventricular contraction. Heart murmurs are produced as a result of turbulent flow of blood strong enough to produce audible noise. They are usually heard as a whooshing sound. The term murmur only refers to a sound believed to originate within blood flow through or near the heart; rapid blood velocity is necessary to produce a murmur. Most heart problems do not produce any murmur and most valve problems also do not produce an audible murmur. Murmurs can be heard in many situations in adults without major congenital heart abnormalities: Though several different

neg: Impulse generator Impulse generator An impulse generator is an electrical apparatus which produces very short high-voltage or high-current surges. Such devices can be classified into two types: impulse voltage generators and impulse current generators. High impulse voltages are used to test the strength of electric power equipment against lightning and switching surges. Also, steep-front impulse voltages are sometimes used in nuclear physics experiments. High impulse currents are needed not only for tests on equipment such as lightning arresters and fuses but also for many other technical applications such as lasers, thermonuclear fusion, and plasma devices. In 1863 Hungarian physicist Ányos Jedlik discovered

neg: History of the location of the soul the heart does not need the brain to move. Galen recognized the importance of both the heart and the brain in the proper functioning of a human but saw these as two distinct system governed separately. Therefore there are two souls in combat, the brain representing the logical soul and driving logical being, the heart representing spirited actions of movement and impulse constantly at odds with each other and supplied by different supporting systems. Galen states the "liver is the archai" or the source of the veins and blood of the body and is therefore important in regards to the

neg: Digital channel election or 20 kW digital), are prone to electromagnetic interference. The ATSC digital TV system has severe problems with susceptibility to impulse noise, bursts of interference which briefly render the entire channel unusable, due to its inability to instantaneously determine where in a video frame to resume display when the signal returns. The result is macroblocking and pixelation of the entire signal whenever impulse noise sources (such as motors, appliances or electrical storms) are active. They also are the lowest in frequency and therefore the longest in wavelength, requiring the largest antennas both to transmit and receive. They are also prone

neg: Infinite impulse response Infinite impulse response Infinite impulse response (IIR) is a property applying to many linear time-invariant systems. Common examples of linear time-invariant systems are most electronic and digital filters. Systems with this property are known as "IIR systems" or "IIR filters", and are distinguished by having an impulse response which does not become exactly zero past a certain point, but continues indefinitely. This is in contrast to a finite impulse response (FIR) in which the impulse response "h"("t") "does" become exactly zero at times "t" > "T" for some finite "T", thus being of finite duration. In practice, the impulse response,

neg: Fusion beat Fusion beat A fusion beat occurs when electrical impulses from different sources act upon the same region of the heart at the same time. If it acts upon the ventricular chambers it is called a ventricular fusion beat, whereas colliding currents in the atrial chambers produce atrial fusion beats. Ventricular fusion beats can occur when the heart's natural rhythm and the impulse from a pacemaker coincide to activate the same part of a ventricle at the same time, causing visible variation in configuration and height of the QRS complex of an electrocardiogram reading of the heart's activity. This contrasts with

neg: Cardiac action potential This is known as the electrical conduction system of the heart, see figure 4. Other than the SAN, the AVN and purkinje fibres also have pacemaker activity and can therefore spontaneously generate an action potential. However, these cells usually do not depolarize spontaneously, simply because, action potential production in the SAN is faster. This means that before the AVN or purkinje fibres reach the threshold potential for an action potential, they are depolarized by the oncoming impulse from the SAN This is called "overdrive suppression". Pacemaker activity of these cells is vital, as it means that if the SAN were

neg: Cardiac skeleton the electrical and autonomic energy generated above is ushered below and cannot return. The cardiac skeleton does this by establishing an electrically impermeable boundary to autonomic electrical influence within the heart. Simply put, the dense connective tissue within the cardiac skeleton does not conduct electricity and its deposition within the myocardial matrix is not accidental. The anchored and electrically inert collagen framework of the four valves allows normal anatomy to house the atrioventricular node (AV node) in its center. The AV node is the only electrical conduit from the atria to the ventricles through the cardiac skeleton, which is why

neg: Heart arrhythmia every direction but will do so only once within a short time. Normally, the action potential impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of refractory period or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm. As a sort of "re-entry", vortices

neg: Universal conductance fluctuations Universal conductance fluctuations Universal conductance fluctuations (UCF) in mesoscopic physics is a phenomenon encountered in electrical transport experiments in mesoscopic species. The measured electrical conductance will vary from sample to sample, mainly due to inhomogeneous scattering sites. Fluctuations originate from coherence effects for electronic wavefunctions and thus the phase-coherence length formula_1 needs be larger than the momentum relaxation length formula_2. UCF is more profound when electrical transport is in weak localization regime. formula_3 where formula_4 , formula_5 is the number of conduction channels and formula_2is the momentum relaxation due to phonon scattering events length or mean free path. For weakly

neg: Apex beat Apex beat The apex beat (lat. ictus cordis), also called the apical impulse, is the pulse felt at the point of maximum impulse (PMI), which is the point on the precordium farthest outwards (laterally) and downwards (inferiorly) from the sternum at which the cardiac impulse can be felt. The cardiac impulse is the vibration resulting from the heart rotating, moving forward and striking against the chest wall during systole. The PMI is not the apex of the heart but is on the precordium not far from it. The normal apex beat can be palpated in the precordium "left 5th intercostal

neg: Binding neuron model, see, e.g., where the BN model is used with refractoriness and fast inhibition. Binding neuron A binding neuron (BN) is an abstract mathematical model of the electrical activity of a neuron, closely related to well-known integrate-and-fire model. The BN model originated in a 1998 paper by A. K. Vidybida For a generic neuron the stimuli are excitatory impulses. Normally, more than single input impulse is necessary for exciting neuron up to the level when it fires and emits an output impulse. Let the neuron receives formula_1 input impulses at consecutive moments of time formula_2. In the BN concept the

neg: Impulse generator This consists of multiple capacitors that are first charged in parallel through charging resistors by a high-voltage, direct-current source and then connected in series and discharged through a test object by a simultaneous spark-over of the spark gaps. The impulse current generator comprises many capacitors that are also charged in parallel by a high-voltage, low-current, direct-current source, but it is discharged in parallel through resistances, inductances, and a test object by a spark gap. Impulse generator An impulse generator is an electrical apparatus which produces very short high-voltage or high-current surges. Such devices can be classified into two types: impulse

neg: Sleep and memory procedure that records electrical activity along the scalp. This procedure cannot record activity from individual neurons, but instead measures the overall average electrical activity in the brain. Electrooculography (EOG) measures the difference in electrical potential between the front and the back of the eye. This does not measure a response to individual visual stimuli, but instead measures general eye movement. Electromyography (EMG) is used to records the electrical activity of skeletal muscles. A device called an electromyograph measures the electrical potential of muscle cells to monitor muscle movement. Electrocardiography (ECG or EKG) measures the electrical depolarization of the heart muscles

neg: Where Does My Heart Beat Now 1994. Dion is also performing "Where Does My Heart Beat Now" in her current Las Vegas residency show, "Celine". On 13 May 1992, "Where Does My Heart Beat Now" received an ASCAP Pop Award for the most-performed ASCAP song during the 1991 survey year (1 October 1990 – 30 September 1991). Additionally, Dion's performance of "Where Does My Heart Beat Now" at the Juno Awards of 1991 was nominated for the Gemini Award in category Best Performance in a Variety Program or Series. Where Does My Heart Beat Now "Where Does My Heart Beat Now" is a song performed by

neg: Electrical conduction system of the heart event of the cycle is the repolarization of the ventricles. It is the restoring of the resting state. In the ECG, repolarization includes the J point, ST segment, and T and U waves. The transthoracically measured PQRS portion of an electrocardiogram is chiefly influenced by the sympathetic nervous system. The T (and occasionally U) waves are chiefly influenced by the parasympathetic nervous system guided by integrated brainstem control from the vagus nerve and the thoracic spinal accessory ganglia. An impulse (action potential) that originates from the SA node at a relative rate of 60-100bpm is known as "normal sinus rhythm".

neg: Emotionality inferiority. In early psychology, it was believed that passion (emotion) was a part of the soul inherited from the animals and that it must be controlled. identified that in the Romantic movement of the eighteenth and nineteenth centuries, reason and emotion were thought to be opposites. Physiological responses to emotion originate in the central nervous system, the autonomic nervous system, and the endocrine system. Some of the responses include: heart rate, sweating, rate and depth of respiration, and electrical activity in the brain. Many researchers have attempted to find a connection between specific emotions and a corresponding pattern of physiological

neg: Pulseless electrical activity although there is little evidence to support this practice. Its routine use is not recommended for patients in this context, except in special situations (e.g. preexisting metabolic acidosis, hyperkalemia, tricyclic antidepressant overdose). All of these drugs should be administered along with appropriate CPR techniques. Defibrillators cannot be used to correct this rhythm, as the problem lies in the response of the myocardial tissue to electrical impulses. Pulseless electrical activity Pulseless electrical activity (PEA), also known as electromechanical dissociation, refers to cardiac arrest in which the electrocardiogram shows a heart rhythm that should produce a pulse, but does not. Pulseless electrical

neg: Electrical burn to the brain, strain to the heart, and injury to other organs. For a burn to be classified as electrical, electricity must be the direct cause. For example, burning a finger on a hot electric steam iron would be thermal, not electrical. According to Joule's first law: electricity passing through resistance creates heat, so there is no current entering the body in this type of burn. Likewise, a fire that is ruled to be "electrical" in origin, does not necessarily mean that any injuries or deaths are due to electrical burns. Unless someone was injured at the exact moment that

neg: Blind deconvolution implicit or explicit. Blind deconvolution In electrical engineering and applied mathematics, blind deconvolution is deconvolution without explicit knowledge of the impulse response function used in the convolution. This is usually achieved by making appropriate assumptions of the input to estimate the impulse response by analyzing the output. Blind deconvolution is not solvable without making assumptions on input and impulse response. Most of the algorithms to solve this problem are based on assumption that both input and impulse response live in respective known subspaces. However, blind deconvolution remains a very challenging non-convex optimization problem even with this assumption. In image processing,

neg: Blind deconvolution Blind deconvolution In electrical engineering and applied mathematics, blind deconvolution is deconvolution without explicit knowledge of the impulse response function used in the convolution. This is usually achieved by making appropriate assumptions of the input to estimate the impulse response by analyzing the output. Blind deconvolution is not solvable without making assumptions on input and impulse response. Most of the algorithms to solve this problem are based on assumption that both input and impulse response live in respective known subspaces. However, blind deconvolution remains a very challenging non-convex optimization problem even with this assumption. In image processing, blind deconvolution is

neg: Mass driver spacecraft acceleration if available input power is constant (less momentum per unit of energy given to propellant). Electric propulsion methods like mass drivers are systems where energy does not come from the propellant itself. (Such contrasts to chemical rockets where propulsive efficiency varies with the ratio of exhaust velocity to vehicle velocity at the time, but near maximum obtainable specific impulse tends to be a design goal when corresponding to the most energy released from reacting propellants). Although the specific impulse of an electric thruster itself optionally could range up to where mass drivers merge into particle accelerators with fractional-lightspeed