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Tachycardia, also called tachyarrhythmia, is a
heart rate Heart rate is the speed of the heartbeat Heartbeat or heartbeats may refer to: Physiology *Cardiac cycle, of the heart *Contraction of the cardiac muscle, muscles of the heart, or a perceived effect of it, such as: **Heart sounds, the noises gene ...

heart rate
that exceeds the normal resting rate. In general, a resting heart rate over 100
beat Beat, beats or beating may refer to: Common meanings Assigned activity or area * Patrol, an area (usually geographic) that one is responsible to monitor, including: ** Beat (police), the territory and time that a police officer patrols ** Beat ...

beat
s per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (such as with
exercise Exercise is any bodily activity that enhances or maintains physical fitness Physical fitness is a state of health Health is a state of physical, mental and social well-being Well-being, also known as ''wellness'', ''prudential value ...

exercise
) or abnormal (such as with electrical problems within the heart).


Complications

Tachycardia can lead to
fainting Syncope, commonly known as fainting, is a loss of consciousness Consciousness, at its simplest, is sentience or awareness of internal and external existence. Despite millennia of analyses, definitions, explanations and debates by philos ...
. When the rate of blood flow becomes too rapid, or fast blood flow passes on damaged
endothelium Endothelium is a single layer of squamous Epithelium () is one of the four basic types of animal Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. Wit ...
, it increases the friction within vessels resulting in turbulence and other disturbances. According to the
Virchow's triad Virchow's triad or the triad of Virchow () describes the three broad categories of factors that are thought to contribute to thrombosis. * Hypercoagulability * Hemodynamic changes (stasis, turbulence) * Endothelial injury/dysfunction It is named ...

Virchow's triad
, this is one of the three conditions that can lead to
thrombosis Thrombosis (from Ancient Greek "clotting”) is the formation of a Thrombus, blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses pla ...

thrombosis
(i.e., blood clots within vessels).


Causes

Some causes of tachycardia include: *
Adrenergic storm An adrenergic storm is a sudden and dramatic increase in serum levels of the catecholamines (noradrenaline) Image:Adrenalin - Adrenaline.svg">140px, epinephrine (adrenaline) A catecholamine (; abbreviated CA) is a monoamine neurotransmitt ...
*
Anaemia Anemia ( also spelled anaemia) is a decrease in the total amount of red blood cell Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, eryt ...
*
Anxiety Anxiety is an emotion Emotions are mental state, psychological states brought on by neurophysiology, neurophysiological changes, variously associated with thoughts, feelings, behavioural responses, and a degree of pleasure or suffering, disp ...

Anxiety
*
Atrial fibrillation Atrial fibrillation (AF or A-fib) is an abnormal heart rhythm (arrhythmia) characterized by the rapid and irregular beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating, which become longer or cont ...

Atrial fibrillation
*
Atrial flutter Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory ...
*
Atrial tachycardia Atrial tachycardia is a type of heart rhythm problem in which the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood carries ...
*
AV nodal reentrant tachycardia AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycar ...

AV nodal reentrant tachycardia
*
Brugada syndrome Brugada syndrome (BrS) is a genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome In the fields of molecular biology and genetics, a genome is all genetic information of an orga ...
*
Circulatory shock Shock is the state of insufficient blood flow to the tissues of the body as a result of problems with the circulatory system The circulatory system, also called the cardiovascular system or the vascular system, is an Biological system, org ...
and its various causes ( obstructive shock,
cardiogenic shock Cardiogenic shock (CS) is a medical emergency resulting from inadequate blood flow due to the dysfunction of the ventricles of the heart.Textbooks of Internal MedicinHarrison's Principles of Internal Medicine 16th Edition, The McGraw-Hill McG ...
,
hypovolemic shock Hypovolemic shock is a medical emergency and an advanced form of hypovolemia due to insufficient amounts of blood and/or fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shea ...
,
distributive shock Distributive shock is a medical Medicine is the art, science Science (from the Latin word ''scientia'', meaning "knowledge") is a systematic enterprise that Scientific method, builds and Taxonomy (general), organizes knowledge in the form ...
) *
Dysautonomia Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system The autonomic nervous system (ANS), formerly the vegetative nervous system, is a division of the peripheral nervous system that supplies smooth muscle an ...
*
Exercise Exercise is any bodily activity that enhances or maintains physical fitness Physical fitness is a state of health Health is a state of physical, mental and social well-being Well-being, also known as ''wellness'', ''prudential value ...

Exercise
*
Fear Fear is an intensely unpleasant emotion Emotions are psychological state A mental state is a state of mind that an agent is in. Most simplistically, a mental state is a mental condition. It is a relation that connects the agent with a pr ...

Fear
*
Hypoglycemia Hypoglycemia, also known as low blood sugar, is a fall in blood sugar The blood sugar level, blood sugar concentration, or blood glucose level is the concentration of glucose Glucose is a simple with the . Glucose is the most abundant , a ...

Hypoglycemia
*
Hypovolemia Hypovolemia, also known as volume depletion or volume contraction, is a state of abnormally low extracellular fluid in the body. This may be due to either a loss of both salt and water or a decrease in blood volume. Hypovolemia refers to the loss ...
*
Hyperthyroidism Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormone File:Thyroid_system.svg, upright=1.5, The thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck ...
*
Hyperventilation Hyperventilation occurs when the rate or tidal volume Tidal volume (symbol VT or TV) is the volume of air moved into or out of the lungs during a normal breath. In a healthy, young human adult, tidal volume is approximately 500 ml per i ...
*
Inappropriate sinus tachycardia Inappropriate sinus tachycardia is a rare type of cardiac arrhythmia within the category of supraventricular tachycardia (SVT). IST may be caused by the Sinoatrial node, sinus node itself having an abnormal structure or function, or it may be part o ...
*
Junctional tachycardia Junctional tachycardia is a form of supraventricular tachycardia characterized by involvement of the AV node. It can be contrasted to atrial tachycardia. It is a tachycardia associated with the generation of impulses in a focus in the region of ...
*
Multifocal atrial tachycardia Multifocal (or multiform) atrial tachycardia (MAT) is an abnormal heart rhythm, specifically a type of supraventricular tachycardia, that is particularly common in older people and is associated with exacerbations of chronic obstructive pulmonary ...
*
Pacemaker A cardiac pacemaker (or artificial pacemaker, so as not to be confused with the natural pacemaker of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the cir ...

Pacemaker
mediated *
Pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain The International Association for the Study of Pain (IASP) is an international learned society A learned societ ...
*
Panic attack Panic attacks are sudden periods of intense fear Fear is an intensely unpleasant emotion Emotions are mental state, psychological states brought on by neurophysiology, neurophysiological changes, variously associated with thoughts, feel ...

Panic attack
*
Pheochromocytoma Pheochromocytoma (PHEO or PCC) is a rare tumor of the adrenal medulla composed of chromaffin cells, also known as pheochromocytes. When a tumor composed of the same cells as a pheochromocytoma develops outside the adrenal gland, it is referred t ...

Pheochromocytoma
*
Sinus tachycardia Sinus tachycardia (also colloquially known as sinus tach or sinus tachy) 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 hea ...
*
Sleep deprivation Sleep deprivation, also known as sleep insufficiency or sleeplessness, is the condition of not having adequate duration and/or quality of sleep Sleep is a Nature, naturally recurring state of mind and body, characterized by altered consciou ...
*
Supraventricular tachycardia Supraventricular tachycardia (SVT) is an umbrella term for arising from the . This is in contrast to the other group of fast heart rhythms - , which start within the . There are four main types of SVT: , , (PSVT) and . The symptoms of SVT incl ...
*
Ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a type of regular, fast heart rate that arises from improper electrical activity in the ventricles of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pump ...
*
Wolff–Parkinson–White syndrome Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood v ...
Drug related: *
Alcohol In chemistry, alcohol is an organic compound that carries at least one hydroxyl functional group (−OH) bound to a Saturated and unsaturated compounds, saturated carbon atom. The term alcohol originally referred to the primary alcohol ethan ...
*
Stimulant Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drug Uncoated tablets, consisting of about 90% acetylsalicylic acid, along with a minor amount of inert fillers and b ...
s *
Cannabis (drug) Cannabis, also known as marijuana among other names Other most often refers to: * Other (philosophy), a concept in psychology and philosophy Other or The Other may also refer to: Books * The Other (Tryon novel), ''The Other'' (Tryon novel), ...
*
Drug withdrawal Drug withdrawal, drug withdrawal syndrome, or substance withdrawal syndrome, is the group of symptom Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may b ...
*
Tricyclic antidepressant Tricyclic antidepressants (TCAs) are a class of medications that are used primarily as antidepressants, which is important for the management of depression. They are second-line drugs next to SSRI. TCAs were discovered in the early 1950s and were ...
s * *
Opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...
s (rare)


Diagnosis

The upper threshold of a normal human resting heart rate is based on age. Cutoff values for tachycardia in different age groups are fairly well standardized; typical cutoffs are listed below: * 1–2 days: Tachycardia >159 beats per minute (bpm) * 3–6 days: Tachycardia >166 bpm * 1–3 weeks: Tachycardia >182 bpm * 1–2 months: Tachycardia >179 bpm * 3–5 months: Tachycardia >186 bpm * 6–11 months: Tachycardia >169 bpm * 1–2 years: Tachycardia >151 bpm * 3–4 years: Tachycardia >137 bpm * 5–7 years: Tachycardia >133 bpm * 8–11 years: Tachycardia >130 bpm * 12–15 years: Tachycardia >119 bpm * >15 years – adult: Tachycardia >100 bpm Heart rate is considered in the context of the prevailing clinical picture. For example, in
sepsis Sepsis is a life-threatening condition that arises when the body's response to infection An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction ...
>90 bpm is considered tachycardia. When the heart beats excessively or rapidly, the heart pumps less efficiently and provides less blood flow to the rest of the body, including the heart itself. The increased heart rate also leads to increased work and oxygen demand by the heart, which can lead to rate related
ischemia Ischemia or ischaemia is a restriction in blood Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the Cell (biology), cells and transports metabolic waste products away fr ...
.Harrison's Principles of Internal Medicine, 17th Edition


Differential diagnosis

An
electrocardiogram Electrocardiography is the process of producing an electrocardiogram (ECG or EKG). It is a graph of voltage Voltage, electric potential difference, electromotive force emf, electric pressure or electric tension is the difference in elec ...

electrocardiogram
(ECG) is used to classify the type of tachycardia. They may be classified into narrow and wide complex based on the
QRS complex The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually the central and most visually obvious part of the tracing; in other words, it's the main spike seen on an E ...

QRS complex
. Equal or less than 0.1s for narrow complex. Presented order of most to least common, they are: * Narrow complex **
Sinus tachycardia Sinus tachycardia (also colloquially known as sinus tach or sinus tachy) 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 hea ...
, which originates from the sino-atrial (SA) node, near the base of the
superior vena cava The superior vena cava (SVC) is the anatomical terms of location#Superior and inferior, superior of the two venae cavae, the great vein, venous trunks that return deoxygenated blood from the circulatory system, systemic circulation to the atrium ...
**
Atrial fibrillation Atrial fibrillation (AF or A-fib) is an abnormal heart rhythm (arrhythmia) characterized by the rapid and irregular beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating, which become longer or cont ...

Atrial fibrillation
**
Atrial flutter Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory ...
**
AV nodal reentrant tachycardia AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycar ...

AV nodal reentrant tachycardia
** Accessory pathway mediated tachycardia **
Atrial tachycardia Atrial tachycardia is a type of heart rhythm problem in which the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pumped blood carries ...
**
Multifocal atrial tachycardia Multifocal (or multiform) atrial tachycardia (MAT) is an abnormal heart rhythm, specifically a type of supraventricular tachycardia, that is particularly common in older people and is associated with exacerbations of chronic obstructive pulmonary ...
**
Cardiac Tamponade Cardiac tamponade, also known as pericardial tamponade, is when fluid in the pericardium (the sac around the heart) builds up, resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of cardiogenic sh ...
**
Junctional tachycardia Junctional tachycardia is a form of supraventricular tachycardia characterized by involvement of the AV node. It can be contrasted to atrial tachycardia. It is a tachycardia associated with the generation of impulses in a focus in the region of ...
(rare in adults) * Wide complex **
Ventricular tachycardia Ventricular tachycardia (V-tach or VT) is a type of regular, fast heart rate that arises from improper electrical activity in the ventricles of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pump ...
, any tachycardia that originates in the ventricles ** Any narrow complex tachycardia combined with a problem with the
conduction system The electrical conduction system of the heart transmits signals generated usually by the sinoatrial node to cause contraction of the heart muscle. The Cardiac pacemaker, pacemaking signal generated in the sinoatrial node travels through the right ...

conduction system
of the heart, often termed "supraventricular tachycardia with aberrancy" ** A narrow complex tachycardia with an accessory conduction pathway, often termed "supraventricular tachycardia with pre-excitation" (e.g.
Wolff–Parkinson–White syndrome Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood v ...
) ** Pacemaker-tracked or pacemaker-mediated tachycardia Tachycardias may be classified as either narrow complex tachycardias (supraventricular tachycardias) or wide complex tachycardias. Narrow and wide refer to the width of the
QRS complex The QRS complex is the combination of three of the graphical deflections seen on a typical electrocardiogram (ECG or EKG). It is usually the central and most visually obvious part of the tracing; in other words, it's the main spike seen on an E ...

QRS complex
on the
ECG Electrocardiography is the process of producing an electrocardiogram (ECG or EKG). It is an electrogram of the heart The heart is a cardiac muscle, muscular Organ (biology), organ in most animals, which pumps blood through the blood ...

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

The body has several
feedback mechanism Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...
s to maintain adequate blood flow and
blood pressure Blood pressure (BP) is the pressure Pressure (symbol: ''p'' or ''P'') is the force In physics, a force is an influence that can change the motion (physics), motion of an Physical object, object. A force can cause an object with mas ...

blood pressure
. If blood pressure decreases, the heart beats faster in an attempt to raise it. This is called
reflex In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechanism ...

reflex
tachycardia. This can happen in response to a decrease in blood volume (through
dehydration In physiology, dehydration is a lack of total body water In physiology Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology Biology is the natural science that studie ...

dehydration
or
bleeding Bleeding, also known as a hemorrhage, haemorrhage, or simply blood loss, is blood Blood is a body fluid Body fluids, bodily fluids, or biofluids are liquid A liquid is a nearly incompressible In fluid mechanics or more generally ...

bleeding
), or an unexpected change in
blood flow Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory system is controlled by homeostasis, homeostatic mechanisms of autoregulation, just as hydraul ...

blood flow
. The most common cause of the latter is
orthostatic hypotension Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure Blood pressure (BP) is the pressure Pressure (symbol: ''p'' or ''P'') is the force In physics Physics (fr ...
(also called postural hypotension).
Fever Fever, also referred to as pyrexia, is defined as having a temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on th ...

Fever
,
hyperventilation Hyperventilation occurs when the rate or tidal volume Tidal volume (symbol VT or TV) is the volume of air moved into or out of the lungs during a normal breath. In a healthy, young human adult, tidal volume is approximately 500 ml per i ...
,
diarrhea Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery defecation, bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration of ...
and severe
infections An infection is the invasion of an organism's body Tissue (biology), tissues by Pathogen, disease-causing agents, their multiplication, and the reaction of host (biology), host tissues to the infectious agents and the toxins they produce. An in ...
can also cause tachycardia, primarily due to increase in
metabolic Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main purposes of metabolism are: the conversion of the energy in food to energy available to run cell ...
demands. An increase in
sympathetic nervous system The sympathetic nervous system (SNS) is one of two divisions of the autonomic nervous system The autonomic nervous system (ANS), formerly the vegetative nervous system, is a division of the peripheral nervous system that supplies smooth muscle ...
stimulation causes the heart rate to increase, both by the direct action of sympathetic nerve fibers on the heart and by causing the
endocrine The endocrine system is a messenger system comprising feedback loops of the hormone A hormone (from the Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Re ...
system to release
hormone A hormone (from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is appr ...

hormone
s such as , which have a similar effect. Increased sympathetic stimulation is usually due to physical or psychological stress. This is the basis for the so-called
fight-or-flight response The fight-or-flight-or-freeze or the fight-flight response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack Attack may refer to: Warfare and comba ...
, but such stimulation can also be induced by
stimulant Stimulants (also often referred to as psychostimulants or colloquially as uppers) is an overarching term that covers many drug Uncoated tablets, consisting of about 90% acetylsalicylic acid, along with a minor amount of inert fillers and b ...
s such as
ephedrine Ephedrine is a medication and stimulant. It is often used to prevent low blood pressure during anesthesia Anesthesia or anaesthesia (from Greek "without sensation") is a state of controlled, temporary loss of sensation or awareness that is ...

ephedrine
,
amphetamines#REDIRECT Substituted amphetamine#REDIRECT Substituted amphetamine Substituted amphetamines are a class of compounds based upon the amphetamine structure; it includes all derivative In mathematics Mathematics (from Ancient Greek, Gre ...
or
cocaine Cocaine (from , from , ultimately from Quechuan languages, Quechua: ''kúka'') is a tropane alkaloid and stimulant drug obtained primarily from the leaves of two coca species native to South America, ''Erythroxylum coca'' and ''Erythroxylu ...

cocaine
. Certain endocrine disorders such as
pheochromocytoma Pheochromocytoma (PHEO or PCC) is a rare tumor of the adrenal medulla composed of chromaffin cells, also known as pheochromocytes. When a tumor composed of the same cells as a pheochromocytoma develops outside the adrenal gland, it is referred t ...

pheochromocytoma
can also cause epinephrine release and can result in tachycardia independent of nervous system stimulation.
Hyperthyroidism Hyperthyroidism is the condition that occurs due to excessive production of thyroid hormone File:Thyroid_system.svg, upright=1.5, The thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck ...
can also cause tachycardia.Barker RL, Burton JR, Zieve, PD eds. Principles of Ambulatory Medicine. Sixth Edition. Philadelphia, PA: Lippinocott, Wilkins & Williams 2003 The upper limit of normal rate for sinus tachycardia is thought to be 220 bpm minus age.


=Inappropriate sinus tachycardia

=
Inappropriate sinus tachycardia Inappropriate sinus tachycardia is a rare type of cardiac arrhythmia within the category of supraventricular tachycardia (SVT). IST may be caused by the Sinoatrial node, sinus node itself having an abnormal structure or function, or it may be part o ...
(IST) is a rare but benign type of cardiac arrhythmia that may be caused by a structural abnormality in the
sinus node The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is a group of Cell (biology), cells located in the wall of the atrium (heart), right atrium of the heart. These Cell (biology), cells have the ability to spontaneously ...
. It can occur in seemingly healthy individuals with no history of cardiovascular disease. Other causes may include Autonomic nervous system deficits, autoimmune response, or drug interactions. Although symptoms might be distressing, treatment is not generally needed.


Ventricular

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. A medically significant subvariant of ventricular tachycardia is called ''
torsades de pointes ''Torsades de pointes, torsade de pointes'' or ''torsades des pointes'' (TdP) (, , translated as "twisting of peaks") is a specific type of abnormal heart rhythm that can lead to sudden cardiac death Cardiac arrest is a sudden loss of blood ...
'' (literally meaning "twisting of the points", due to its appearance on an EKG), which tends to result from a long QT interval. Both of these rhythms normally last for only a few
second The second (symbol: s, also abbreviated: sec) is the base unit of time Time is the continued sequence of existence and event (philosophy), events that occurs in an apparently irreversible process, irreversible succession from the past, th ...
s to
minute The minute is a unit Unit may refer to: Arts and entertainment * UNIT Unit may refer to: Arts and entertainment * UNIT, a fictional military organization in the science fiction television series ''Doctor Who'' * Unit of action, a discrete piec ...
s'' (
paroxysmal tachycardia Paroxysmal tachycardia is a form of tachycardia which begins and ends in an Acute (medicine), acute (or paroxysmal) manner. It is also known as "Bouveret-Hoffmann syndrome". Cause The cause of this condition is not accurately known, though it is ...
)'', but if VT persists it is extremely dangerous, often leading to
ventricular fibrillation Ventricular fibrillation (V-fib or VF) is an abnormal heart rhythm in which the Ventricle (heart), ventricles of the heart Fibrillation, quiver. It is due to disorganized electrical conduction system of the heart, electrical activity. Ventricular ...

ventricular fibrillation
.


Supraventricular

This is a type of tachycardia that originates from above the ventricles, such as the atria. It is sometimes known as paroxysmal atrial tachycardia (PAT). Several types of supraventricular tachycardia are known to exist.


=Atrial fibrillation

=
Atrial fibrillation Atrial fibrillation (AF or A-fib) is an abnormal heart rhythm (arrhythmia) characterized by the rapid and irregular beating of the atrial chambers of the heart. It often begins as short periods of abnormal beating, which become longer or cont ...

Atrial fibrillation
is one of the most common cardiac arrhythmias. In general, it is an irregular, narrow complex rhythm. However, it may show wide QRS complexes on the ECG if a
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 electrical conduction system of the heart transmits signals generated usually by the sinoatrial node to cause contraction ...

bundle branch block
is present. At high rates, the QRS complex may also become wide due to the
Ashman phenomenon Ashman phenomenon, also known as Ashman beats, describes a particular type of wide QRS complex, often seen isolated that is typically seen in atrial fibrillation. It is more often misinterpreted as a premature ventricular complex. It is named for ...
. 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 pathwayAn accessory pathway is an additional electrical connection between two parts of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pump ...
is present). However, new-onset atrial fibrillation tends to present with rates between 100 and 150 beats per minute.


=AV nodal reentrant tachycardia

=
AV nodal reentrant tachycardia AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycar ...

AV nodal reentrant tachycardia
(AVNRT) is the most common reentrant tachycardia. It is a regular narrow complex tachycardia that usually responds well to the
Valsalva maneuver The Valsalva maneuver is performed by moderately forceful attempted exhalation Exhalation (or expiration) is the flow of the breath upright=1.4, X-ray video of a female American alligator while breathing. Breathing (or ventilation) is ...

Valsalva maneuver
or the drug
adenosine Adenosine is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, bonds. Due to carbon's ability to Catenation, cate ...

adenosine
. However, unstable patients sometimes require synchronized
cardioversion Cardioversion is a medical procedure A medical procedure is a course of action intended to achieve a result in the delivery of healthcare. A medical procedure with the intention of determining, measuring, or diagnosing a patient condition or para ...

cardioversion
. Definitive care may include
catheter ablation Catheter ablation is a procedure used to remove or terminate a faulty electrical pathway from sections of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the ci ...
.


=AV reentrant tachycardia

= AV reentrant tachycardia (AVRT) requires an
accessory pathwayAn accessory pathway is an additional electrical connection between two parts of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pumps blood through the blood vessels of the circulatory system. The pump ...
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 Ventricular tachycardia (V-tach or VT) is a type of regular, fast heart rate that arises from improper electrical activity in the ventricles of the heart The heart is a muscle, muscular Organ (anatomy), organ in most animals, which pump ...
. Most
antiarrhythmics Antiarrhythmic agents, also known as cardiac dysrhythmia medications, are a group of pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to medical diagnosis, di ...
are
contraindicatedIn medicine Medicine is the Art (skill), art, science, and Praxis (process) , practice of caring for a patient and managing the diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment or Palliative care , palliation of their inj ...
in the emergency treatment of AVRT, because they may paradoxically increase conduction across the accessory pathway.


=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.


Management

The management of tachycardia depends on its type (wide complex versus narrow complex), whether or not the person is stable or unstable, and whether the instability is due to the tachycardia. Unstable means that either important organ functions are affected or
cardiac arrest Cardiac arrest is a sudden loss of blood flow Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynamics, dynamics of blood flow. The circulatory system is controlled by homeostasis, homeost ...
is about to occur.


Unstable

In those that are unstable with a narrow complex tachycardia, intravenous
adenosine Adenosine is an organic compound , CH4; is among the simplest organic compounds. In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen chemical bond, bonds. Due to carbon's ability to Catenation, cate ...

adenosine
may be attempted. In all others immediate
cardioversion Cardioversion is a medical procedure A medical procedure is a course of action intended to achieve a result in the delivery of healthcare. A medical procedure with the intention of determining, measuring, or diagnosing a patient condition or para ...

cardioversion
is recommended.


Terminology

The word ''tachycardia'' came to English from
New Latin New Latin (also called Neo-Latin or modern Latin) is the revival of Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, know ...
as a
neoclassical compound Neoclassical or neo-classical may refer to: * Neoclassicism Neoclassicism (also spelled Neo-classicism; from Ancient Greek, Greek νέος ''nèos'', "new" and Ancient Greek, Greek κλασικός ''klasikόs'', "of the highest rank") was a W ...
built from the combining forms '' tachy-'' + '' -cardia'', which are from the
Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population is approximately 10.7 million as of ...
ταχύς ''tachys'', "quick, rapid" and καρδία, ''kardia'', "heart". As a matter both of
usage The usage of a language A language is a structured system of communication used by humans, including speech (spoken language), gestures (Signed language, sign language) and writing. Most languages have a writing system composed of glyphs to in ...
choices in the
medical literature at the Rare Book Room, New York Academy of Medicine The New York Academy of Medicine (the Academy) is a health policy and advocacy organization founded in 1847 by a group of leading New York metropolitan area The New York metropolitan area is ...
and of
idiom An idiom is a phrase In syntax and grammar, a phrase is a group of words which act together as a grammatical unit. For instance, the English language, English expression "the very happy squirrel" is a noun phrase which contains the adjective phra ...
in
natural language In neuropsychology Neuropsychology is a branch of psychology. It is concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on ...
, the words ''tachycardia'' and ''tachyarrhythmia'' are usually used interchangeably, or loosely enough that precise differentiation is not explicit. Some careful writers have tried to maintain a logical differentiation between them, which is reflected in major medical dictionaries and major general dictionaries. The distinction is that ''tachycardia'' be reserved for the rapid heart rate itself, regardless of cause, physiologic or pathologic (that is, from healthy response to exercise or from
cardiac arrhythmia Arrhythmia, also known as cardiac arrhythmia or heart arrhythmia, is a group of conditions in which the heartbeat is irregular, too fast, or too slow. The heart rate that is too fast – above 100 beats per minute in adults – is called tach ...
), and that ''tachyarrhythmia'' be reserved for the pathologic form (that is, an arrhythmia of the rapid rate type). This is why five of the previously referenced dictionaries do ''not'' enter cross-references indicating
synonym A synonym is a word, morpheme A morpheme is the smallest meaningful lexical item in a language. A morpheme is not a word. The difference between a morpheme and a word is that a morpheme bound and free morphemes, sometimes does not stand alone ...
y between their entries for the two words (as they do elsewhere whenever synonymy is meant), and it is why one of them explicitly specifies that the two words not be confused. But the prescription will probably never be successfully imposed on general
usage The usage of a language A language is a structured system of communication used by humans, including speech (spoken language), gestures (Signed language, sign language) and writing. Most languages have a writing system composed of glyphs to in ...
, not only because much of the existing medical literature ignores it even when the words stand alone but also because the terms for specific types of arrhythmia (standard collocations of adjectives and noun) are deeply established idiomatically with the ''tachycardia'' version as the more commonly used version. Thus SVT is called
supraventricular tachycardia Supraventricular tachycardia (SVT) is an umbrella term for arising from the . This is in contrast to the other group of fast heart rhythms - , which start within the . There are four main types of SVT: , , (PSVT) and . The symptoms of SVT incl ...
more than twice as often as it is called supraventricular tachyarrhythmia; moreover, those two terms are always completely synonymous—in natural language there is no such term as "healthy/physiologic supraventricular tachycardia". The same themes are also true of AVRT and
AVNRT AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal tachycardia, fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentran ...

AVNRT
. Thus this pair is an example of when a particular prescription (which may have been tenable 50 or 100 years earlier) can no longer be invariably enforced without violating idiom. But the power to differentiate in an idiomatic way is not lost, regardless, because when the specification of physiologic tachycardia is needed, that phrase aptly conveys it.


See also

*
Postural orthostatic tachycardia syndrome Postural orthostatic tachycardia syndrome (POTS) is a condition in which a change from lying A lie is an assertion that is believed to be false, typically used with the purpose of deceiving someone. The practice of communicating lies is c ...


References


External links

{{Authority control Cardiac arrhythmia Symptoms and signs: Cardiac