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Automatic Tachycardia
An automatic tachycardia is a cardiac arrhythmia which involves an area of the heart generating an abnormally fast rhythm, sometimes also called enhanced automaticity. These tachycardias, or fast heart rhythms, differ from reentrant tachycardias ( AVRT and AVNRT) in which there is an abnormal electrical pathway which gives rise to the pathology. Most automatic tachycardias are supraventricular tachycardias (SVT). It is important to recognise an automatic tachycardia because the treatment will be different to that for a reentrant tachycardia. The most useful clue will be the presence of 'warm up' and 'cool down'. This means that whereas a reentrant tachycardia will both begin and end abruptly as cardiac conduction utilises then ceases to utilise the accessory pathway, an automatic tachycardia will rise and fall gradually in rate as the automatic focus increases and decreases its automatic rate of electrical discharge.Lister B et al. Paediatric BASIC: Basic Assessment and Support in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinus Tachycardia
Sinus tachycardia is an elevated sinus rhythm characterized by an increase in the rate of electrical impulses arising from the sinoatrial node. In adults, sinus tachycardia is defined as a heart rate greater than 100 beats per minute (bpm). The normal resting heart rate is 60–90 bpm in an average adult. Normal heart rates vary with age and level of fitness, from infants having faster heart rates (110-150 bpm) and the elderly having slower heart rates. Sinus tachycardia is a normal response to physical exercise, when the heart rate increases to meet the body's higher demand for energy and oxygen, but sinus tachycardia can also indicate a health problem. Thus, sinus tachycardia is a medical finding that can be either physiological or pathological. Signs and symptoms Tachycardia is often asymptomatic. It is often a resulting symptom of a primary disease state and can be an indication of the severity of a disease. If the heart rate is too high, cardiac output may fall due to the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerated Idioventricular Rhythm
Accelerated idioventricular rhythm is a ventricular rhythm with a rate of between 40 and 120 beats per minute. Idioventricular means “relating to or affecting the cardiac ventricle alone” and refers to any ectopic ventricular arrhythmia. Accelerated idioventricular arrhythmias are distinguished from ventricular rhythms with rates less than 40 ( ventricular escape) and those faster than 120 (ventricular tachycardia). Though some other references limit to between 60 and 100 beats per minute. It is also referred to as AIVR and "slow ventricular tachycardia." It can be present at birth. However, it is more commonly associated with reperfusion after myocardial injury. AIVR is generally considered to be a benign abnormal heart rhythm. It is typically temporary and does not require treatment. Pathophysiology 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 p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Conduction System Of The Heart
The cardiac conduction system (CCS) (also called the electrical conduction system of the heart) transmits the signals generated by the sinoatrial node – the heart's pacemaker, to cause the heart muscle to contract, and pump blood through the body's circulatory system. The pacemaking signal travels through the right atrium to the atrioventricular node, along the bundle of His, and through the bundle branches to Purkinje fibers in the walls of the ventricles. The Purkinje fibers transmit the signals more rapidly to stimulate contraction of the ventricles. The conduction system consists of specialized heart muscle cells, situated within the myocardium. There is a skeleton of fibrous tissue that surrounds the conduction system which can be seen on an ECG. Dysfunction of the conduction system can cause irregular heart rhythms including rhythms that are too fast or too slow. Structure Electrical signals arising in the SA node (located in the right atrium) stimulate the atr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinical Cardiac Electrophysiology
{{unreferenced, date=February 2009 Clinical cardiac electrophysiology (also referred to as cardiac electrophysiology, arrhythmia services, or electrophysiology), is a branch of the medical specialty of cardiology and is concerned with the study and treatment of rhythm disorders of the heart. Cardiologists with expertise in this area are usually referred to as electrophysiologists. Electrophysiologists are trained in the mechanism, function, and performance of the electrical activities of the heart. Electrophysiologists work closely with other cardiologists and cardiac surgeons to assist or guide therapy for heart rhythm disturbances (arrhythmias). They are trained to perform interventional and surgical procedures to treat cardiac arrhythmia. The training required to become an electrophysiologist is lengthy and requires eight years after medical school (in the U.S.), entailing three years of internal medicine residency, three years of clinical cardiology fellowship, and two years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Ectopy
Ectopic beat 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 (PVC), or a premature atrial contraction (PAC). Some patients describe this experience as a "flip" or a "jolt" in the chest, or a "heart hiccup", while others report dropped or missed beats. Ectopic beats are more common during periods of psychological stress, exercise or debility; they may also be triggered by consumption of some food like carbohydrates, strong cheese, or chocolate. It is a form of cardiac arrhythmia in which ectopic foci within either ventricular or atrial myocardium, or from finer branches of the electric transduction system, cause additional beats of the heart. Some medications may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ablation
Ablation ( la, ablatio – removal) is removal or destruction of something from an object by vaporization, chipping, erosion, erosive processes or by other means. Examples of ablative materials are described below, and include spacecraft material for ascent and atmospheric reentry, ice and snow in glaciology, biological tissues in medicine and passive fire protection materials. Artificial intelligence In artificial intelligence (AI), especially machine learning, Ablation (artificial intelligence), ablation is the removal of a component of an AI system. The term is by analogy with biology: removal of components of an organism. Biology Biological ablation is the removal of a biological structure or functionality. Genetic ablation is another term for gene silencing, in which gene expression is abolished through the alteration or deletion of genetic sequence information. In cell ablation, individual cells in a population or culture are destroyed or removed. Both can be used as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overdrive Pacing
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] |
Cardiac Pacing
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] |
Antidysrhythmic
Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceuticals that are used to suppress abnormally fast rhythms ( tachycardias), such as atrial fibrillation, supraventricular tachycardia and ventricular tachycardia. Many attempts have been made to classify antiarrhythmic agents. Many of the antiarrhythmic agents have multiple modes of action, which makes any classification imprecise. Vaughan Williams classification The Vaughan Williams classification was introduced in 1970 by Miles Vaughan Williams.Vaughan Williams, EM (1970) "Classification of antiarrhythmic drugs". In ''Symposium on Cardiac Arrhythmias'' (Eds. Sandoe E; Flensted-Jensen E; Olsen KH). Astra, Elsinore. Denmark (1970) Vaughan Williams was a pharmacology tutor at Hertford College, Oxford. One of his students, Bramah N. Singh, contributed to the development of the classification system. The system is therefore sometimes known as the Singh-Vaughan Williams classification. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ventricle (heart)
A ventricle is one of two large chambers toward the bottom of the heart that collect and expel blood towards the peripheral beds within the body and lungs. The blood pumped by a ventricle is supplied by an atrium, an adjacent chamber in the upper heart that is smaller than a ventricle. Interventricular means between the ventricles (for example the interventricular septum), while intraventricular means within one ventricle (for example an intraventricular block). In a four-chambered heart, such as that in humans, there are two ventricles that operate in a double circulatory system: the right ventricle pumps blood into the pulmonary circulation to the lungs, and the left ventricle pumps blood into the systemic circulation through the aorta. Structure Ventricles have thicker walls than atria and generate higher blood pressures. The physiological load on the ventricles requiring pumping of blood throughout the body and lungs is much greater than the pressure generated by the atria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atrioventricular Node
The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of the interatrial septum near the opening of the coronary sinus, and conducts the normal electrical impulse from the atria to the ventricles. The AV node is quite compact (~1 x 3 x 5 mm).Full Size Picture triangle of-Koch.jpg Retrieved on 2008-12-22 Structure Location The AV node lies at the lower back section of the |
Cardiac Arrhythmia
Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be lightheadedness, passing out, shortness of breath or chest pain. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in sudden death. Arrhythmias are often categorized into four groups: extra beats, supraventricular tachycardias, ventricular arrhythmias and bradyarrhythmias. Extra beats include premature atrial contractions, premature ventricular contra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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