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Encyclopedia > Tachycardia
12 lead electrocardiogram showing a run of ventricular tachycardia (VT)
Name of Symptom/Sign:
Tachycardia
Classifications and external resources
ICD-10 R00.0
ICD-9 785.0

Tachycardia refers to a rapid beating of the heart. By convention the term refers to heart rates greater than 100 beats per minute in the adult patient. Tachycardia may be a perfectly normal physiological response to stress. However, depending on the mechanism of the tachycardia and the health status of the patient, tachycardia may be harmful, and require medical treatment. In extreme cases, tachycardia can be life threatening. Image File history File links Download high-resolution version (1088x570, 474 KB) 12 lead electrocardiogram of ventricular tachycardia. ... Image File history File links Download high-resolution version (1088x570, 474 KB) 12 lead electrocardiogram of ventricular tachycardia. ... “QRS” redirects here. ... The term symptom (from the Greek meaning chance, mishap or casualty, itself derived from συμπιπτω meaning to fall upon or to happen to) has two similar meanings in the context of physical and mental health: Strictly, a symptom is a sensation or change in health function experienced by a patient. ... In medicine, a sign is a feature of disease as detected by the doctor during physical examination of a patient. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The heart and lungs, from an older edition of Grays Anatomy. ... Heart rate is a term used to describe the frequency of the cardiac cycle. ... For the adult insect stage, see Imago. ...


Tachycardia can be harmful in two ways. First, when the heart beats too rapidly, it may pump blood less efficiently. Second, the faster the heart beats, the more oxygen and nutrients the heart requires. This may leave patients feeling out of breath or cause angina. This can be especially problematic for patients suffering from ischemic heart disease. General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... angina tonsillaris see tonsillitis. ... Ischaemic heart disease is a disease characterized by reduced blood supply to the heart. ...

Contents

Haemodynamic responses

The body contains several feedback mechanisms to maintain adequate blood flow and blood pressure. If blood pressure decreases, the heart beats faster in an attempt to raise it. This is called reflex tachycardia. In cybernetics and control theory, feedback is a process whereby some proportion or in general, function, of the output signal of a system is passed (fed back) to the input. ... A sphygmomanometer, a device used for measuring blood pressure. ... A reflex action or reflex is a biological control system linking stimulus to response and mediated by a reflex arc. ...


This can happen in response to a decrease in blood volume (through dehydration or bleeding), or an unexpected change in blood flow. The most common cause of the latter is orthostatic hypotension (also called postural hypotension), a sudden drop of blood pressure that occurs with a change in body position (e.g., going from lying down to standing up). When tachycardia occurs for this reason, it is called postural orthostatic tachycardia syndrome (POTS). Blood volume is a term describing the amout of blood (including both red blood cells and plasma) in a persons circulatory system. ... Dehydration (hypohydration) is the removal of water (hydro in ancient Greek) from an object. ... Blood from a finger Bleeding is the loss of blood from the body. ... Blood flow is the flow of blood in the cardiovascular system. ... Orthostatic hypotension (also known as postural hypotension and, colloquially, as head rush or a dizzy spell) is a sudden fall in blood pressure, typically greater than 20/10 mm Hg, that occurs when a person assumes a standing position. ... Orthostatic hypotension (also known as postural hypotension) is a sudden fall in blood pressure that occurs when a person assumes a standing position. ... Postural orthostatic tachycardia syndrome (or POTS) is a condition of orthostatic intolerance in which a change from the supine position to an upright position causes an abnormally-high increase in heart rate. ...


Fever and infection leading to sepsis are also common causes of tachycardia, primarily due to increase in metabolic demands and compensatory increase in heart rate. An analogue medical thermometer showing the temperature of 38. ... An infection is the detrimental colonization of a host organism by a foreign species. ... Sepsis (in Greek Σήψις, putrefaction) is a serious medical condition, resulting from the immune response to a severe infection. ... Santorio Santorio (1561-1636) in his steelyard balance, from Ars de statica medecina, first published 1614 Metabolism (from μεταβολισμος(metavallo), the Greek word for change), in the most general sense, is the ingestion and breakdown of complex compounds, coupled...


Autonomic and endocrine causes

An increase in sympathetic nervous system stimulation causes the heart rate to increase, both by the direct action of sympathetic nerve fibers on the heart and by causing the endocrine system to release hormones such as epinephrine (adrenaline), which have a similar effect. Increased sympathetic stimulation is usually due to physical or psychological stress (the so-called "fight or flight" response), but can also be induced by stimulants such as amphetamines. Grays FIG. 838– The right sympathetic chain and its connections with the thoracic, abdominal, and pelvic plexuses. ... Anatomy and Physiology of the A.N.S. In contrast to the voluntary nervous system, the involuntary or autonomic nervous system is responsible for homeostasis, maintaining a relatively constant internal environment by controlling such involuntary functions as digestion, respiration, and metabolism, and by modulating blood pressure. ... The endocrine system is a control system of ductless endocrine glands that secrete chemical messengers called hormones that circulate within the body via the bloodstream to affect distant organs. ... Norepinephrine A hormone (from Greek όρμή - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... Adrenaline redirects here. ... This article or section should include material from Fight-or-flight The flight or fight response, also called the acute stress response, was first described by Walter Cannon in the 1920s as a theory that animals react to threats with a general discharge of the sympathetic nervous system. ... Stimulants are drugs that temporarily increase alertness and wakefulness. ... Amphetamine is a synthetic drug originally developed (and still used) as an appetite suppressant. ...


Endocrine disorders such as pheochromocytoma can cause epinephrine release and tachycardia independent of the nervous system. Hyperthyroidism is also known to cause tachycardia. Endocrinology is a branch of medicine dealing with disorders of the endocrine system and its specific secretions called hormones. ... A pheochromocytoma (also phaeochromocytoma, English spelling) is a tumor of the medulla of the adrenal glands originating in the chromaffin cells, which secretes excessive amounts of catecholamines, usually epinephrine and norepinephrine. ... Hyperthyroidism (or overactive thyroid gland) is the clinical syndrome caused by an excess of circulating free thyroxine (T4) or free triiodothyronine (T3), or both. ...


Cardiac arrhythmias

The 12 lead ECG can help distinguish between the various types of tachycardias, which may include: “QRS” redirects here. ...

It is sometimes useful to classify tachycardias as either narrow complex tachycardias (often referred to as supraventricular tachycardias) or wide complex tachycardias. "Narrow" and "wide" refer to the width of the QRS complex on the ECG. Narrow complex tachycardias tend to originate in the atria, while wide complex tachycardias tend to originate in the ventricles. Tachycardias can be further classified as either regular or irregular. Sinus tachycardia is a rhythm with elevated rate of impulses originating from the SA node, defined as a rate greater than 100 beats/min in an average adult. ... Atrial fibrillation (AF or afib) is an abnormal heart rhythm (cardiac arrhythmia) which involves the two small, upper heart chambers (the atria). ... AV nodal reentrant tachycardia (AVNRT) is a type of reentrant tachycardia (fast rhythm) of the heart. ... Ventricular tachycardia (V-tach or VT) is a fast rhythm that originates in one of the ventricles of the heart. ... ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ...


Sinus tachycardia

The most common type of tachycardia is sinus tachycardia, which is the body's normal reaction to stress, including fever, dehydration, or blood loss (shock). It is a technical narrow complex tachycardia. In the absence of heart disease, it tends to have a narrow QRS complex on the ECG. Treatment is generally directed at identifying the underlying cause. Sinus tachycardia is a rhythm with elevated rate of impulses originating from the SA node, defined as a rate greater than 100 beats/min in an average adult. ... A supraventricular tachycardia (SVT) is a rapid rhythm of the heart in which the origin of the electrical signal is either the atria or the AV node. ...


Atrial fibrillation

Atrial fibrillation is one of the most common cardiac arrhythmias. It is generally an irregular, narrow complex rhythm. However, it may show wide QRS complexes on the ECG if a bundle branch block is present. At high rates, the QRS complex may also become wide due to the Ashman phenomenon. It may be difficult to determine the rhythm's regularity when the rate exceeds 150 beats per minute. Depending on the patient's health and other variables such as medications taken for rate control, atrial fibrillation may cause heart rates that span from 50 to 250 beats per minute (or even higher if an accessory pathway is present). However, new onset atrial fibrillation tends to present with rates between 100 and 150 beats per minute. Atrial fibrillation (AF or afib) is an abnormal heart rhythm (cardiac arrhythmia) which involves the two small, upper heart chambers (the atria). ... Bundle branch block refers to a disorder of the hearts electrical conducting system. ... The Ashman phenomenon, also known as Ashman beats, describes a particular type of wide complex tachycardia (fast rhythm of the heart) that is often seen in atrial fibrillation. ... Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles of the heart due to an accessory pathway known as the Bundle of Kent. ...


AV nodal reentrant tachycardia (AVNRT)

AV nodal reentrant tachycardia is the most common reentrant tachycardia. It is a regular narrow complex tachycardia that usually responds well to vagal maneuvers or the drug adenosine. However, unstable patients sometimes require synchronized cardioversion. Definitive care may include catheter ablation. AV nodal reentrant tachycardia (AVNRT) is a type of reentrant tachycardia (fast rhythm) of the heart. ... A supraventricular tachycardia (SVT) is a rapid rhythm of the heart in which the origin of the electrical signal is either the atria or the AV node. ... Adenosine is a nucleoside comprised of adenine attached to a ribose (ribofuranose) moiety via a β-N9-glycosidic bond. ... Catheter ablation is an invasive procedure used to remove a faulty electrical pathway from the hearts of those who are prone to developing cardiac arrhythmias such as supraventricular tachycardias (SVT) and Wolff-Parkinson-White syndrome. ...


AV reentrant tachycardia

AV reentrant tachycardia (AVRT) requires an accessory pathway for its maintenance. AVRT may involve orthodromic conduction (where the impulse travels down the AV node to the ventricles and back up to the atria through the accessory pathway) or antidromic conduction (which the impulse travels down the accessory pathway and back up to the atria through the AV node). Orthodromic conduction usually results in a narrow complex tachycardia, and antidromic conduction usually results in a wide complex tachycardia that often mimics ventricular tachycardia. Most antiarrhythmics are contraindicated in the emergency treatment of AVRT, because they may paradoxically increase conduction across the accessory pathway. Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles of the heart due to an accessory pathway known as the Bundle of Kent. ... Ventricular tachycardia (V-tach or VT) is a fast rhythm that originates in one of the ventricles of the heart. ...


Junctional tachycardia

Junctional tachycardia is an automatic tachycardia originating in the AV junction. It tends to be a regular, narrow complex tachycardia and may be a sign of digitalis toxicity.


Ventricular tachycardia

Ventricular tachycardia (VT or V-tach) is a potentially life threatening cardiac arrhythmia that originates in the ventricles. It is usually a regular, wide complex tachycardia with a rate between 120 and 250 beats per minute. Ventricular tachycardia has the potential of degrading to the more serious ventricular fibrillation. Ventricular tachycardia is a common, and often lethal, complication of a myocardial infarction (heart attack). Ventricular tachycardia (V-tach or VT) is a fast rhythm that originates in one of the ventricles of the heart. ... Ventricular fibrillation (V-fib or VF) is a cardiac condition which consists of a lack of coordination of the contraction of the muscle tissue of the large chambers of the heart that eventually leads to the heart stopping altogether. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ...


Exercise-induced ventricular tachycardia is a phenomenon related to sudden deaths, especially in patients with severe heart disease (ischaemia, acquired valvular heart and congenital heart disease) accompanied with left ventricular dysfunction.[1] A case of a death from exercise-induced VT was the death on a basketball court of Hank Gathers, the Loyola Marymount basketball star, in March 1990.[2] A cardiac arrest, or circulatory arrest, is the abrupt cessation of normal circulation of the blood due to failure of the heart to contract effectively during systole. ... In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. ... Wikipedia does not yet have an article with this exact name. ... Cross-section of a healthy heart. ... In the heart, a ventricle is a chamber which collects blood from an atrium (another heart chamber) and pumps it out of the heart. ... This page is a candidate to be moved to Wiktionary. ... Hank Gathers, basketball player for Loyola Marymount University, in a typical moment of his famous jocularity, at Sportscasters Camps of America in Los Angeles in 1989. ... Loyola Marymount University, also referred to as LMU, is a private, co-educational Roman Catholic university in the United States. ... Sara Giauro shoots a three-point shot, FIBA Europe Cup for Women Finals 2005. ... March is the third month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... MCMXC redirects here; for the Enigma album, see MCMXC a. ...


Both of these rhythms normally last for only a few seconds to minutes (paroxysmal tachycardia), but if VT persists it is extremely dangerous, often leading to ventricular fibrillation. Look up second in Wiktionary, the free dictionary. ... A minute is a unit of time equal to 1/60th of an hour and to 60 seconds. ... Paroxysm can have several meanings. ... Ventricular fibrillation (V-fib or VF) is a cardiac condition which consists of a lack of coordination of the contraction of the muscle tissue of the large chambers of the heart that eventually leads to the heart stopping altogether. ...


Treatments

Treatment of tachycardia is usually directed at chemical conversion (with antiarrythmics), electrical conversion (giving external shocks to convert the heart to a normal rhythm) or use of drugs to simply control heart rate (for example as in atrial fibrillation). Antiarrhythmic agents are a group of pharmaceuticals that are used to suppress fast rhythms of the heart (cardiac arrhythmias), such as atrial fibrillation, atrial flutter, ventricular tachycardia, and ventricular fibrillation. ... Atrial fibrillation (AF or afib) is an abnormal heart rhythm (cardiac arrhythmia) which involves the two small, upper heart chambers (the atria). ...


The treatment modality used depends on the type of tachycardia and the hemodynamic stability of the patient. If the tachycardia originates from the sinus node (sinus tachycardia), treatment of the underlying cause of sinus tachycardia is usually sufficient. On the other hand, if the tachycardia is of a potentially lethal origin (ie: ventricular tachycardia) treatment with anti arrhythmic agents or with electrical cardioversion may be required.


Above all, the treatment modality is tailored to the individual, and varies based the mechanism of the tachycardia (where it is originating from within the heart), on the duration of the tachycardia, how well the individual is tolerating the fast heart rate, the likelihood of recurrence once the rhythm is terminated, and any co-morbid conditions the individual is suffering from.


References

External links

  • Postural Orthostatic Tachycardia Syndrome - overview from Dysautonomia Information Network
  • Heart Arrhythmias Respond to Ablation UCLA Healthcare

  Results from FactBites:
 
Tachycardia - Wikipedia, the free encyclopedia (546 words)
Tachycardia is an abnormally rapid beating of the heart, defined as a resting heart rate of 100 or more beats per minute in an average adult.
Tachycardia is a general symptomatic term that does not describe the cause of the rapid rate.
Ventricular tachycardia (VT or "V-tach") is a similar phenomenon occurring within the tissue of the ventricles, causing an extremely rapid rate with poor pumping action.
Sinus tachycardia - Wikipedia, the free encyclopedia (491 words)
Sinus tachycardia is a rhythm with elevated rate of impulses originating from the SA node, defined as a rate greater than 100 beats/min in an average adult.
Sinus tachycardia is usually a response to normal physiological situations, such as exercise and an increased sympathetic tone with increased catecholamine release --- stress, fright, flight, anger.
Sinus tachycardia accompanying a myocardial infarction may be indicative of cardiogenic shock.
  More results at FactBites »

 
 

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