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Postural orthostatic

tachycardia syndrome

POTS

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Descriere

Este o condiie a disautonomiei, mai specific, ointoleran ortostatic, n care trecerea de la clino laortostatism produce o tahicardie anormal; de cele maimulte ori se acompaniaz cu o scdere a TA. Debitul

sanguin cerebral scade. Pacienii cu POTS au problemen a-i menine homeostazia fluidelor la schimbareapoziiei, ex. deplasarea de pe un scaun pe altul sauatingerea unor obiecte aflate lanlime, deasupra

capului. Muli dintre ei sunt simptomatici n repaus.

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Simptomatologie 2

Esena POTS este o cretere a AV la trecereadin clino n ortostatism cu mai mult de 30 btipe minut sau la o frecven mai mare de 120

bti pe minut n primele 10 minutes de la head-up tilt. Aceast tahicardie este deseoriacompaniat de o hipotensiune arterialsimptomatic:

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ameeli, uneori pre-sincope (pre-lipotimie)(nu vertij)

Intoleran la efort

Fatigabilitate extrem

Sincope.

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Hipoperfuzia tisular produce:

Extremiti reci

Dureri toracice i disconfort toracic

dezorientare dispnee

cefalee

Slbiciune muscular tremurturi

Tulburri vizuale

http://en.wikipedia.org/wiki/Disorientationhttp://en.wikipedia.org/wiki/Disorientationhttp://en.wikipedia.org/wiki/Disorientationhttp://en.wikipedia.org/wiki/Disorientation

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Disfuncia sistemului autonom poate cauzasimptome gastrointestinale:

Dureri abdominale sau discomfort

balonri

constipaie diaree

greuri

vrsturi

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Hipoperfuzia cerebral producedificulti cognitive i emoionale:

Cea pe creier

epuizare

scderea forei mentale depresie

dificultin gsirea cuvntului corect

Capacitate redus de concentraie Tulburri de somn

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Niveluri nepotrivite de adrenalin i noradrenalinpot produce simptome anxiety-like:

frisoane

anxietate

flushing

hipertermie

Nervozitate

Simptomele de POTS se pot suprapune peste

cele ale tulburrilor anxioase, cu care se poateconfunda.

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Associated conditions

POTS is often accompanied by vasovagal syncope, alsocalled "neurally mediated hypotension" (NMH) or"neurocardiogenic syncope" (NCS). Vasovagal syncopeis a fainting reflex due to a profound drop in blood

pressure. Autonomic disfunction that occurs with thesedisorders causes blood to inappropriately pool in thelimbs away from the heart, lungs, and brain. Thecombination of misdirected bloodflow and hypotension

will invoke syncope. Tachycardia associated with POTSmay be a cardiac response to restore cerebralhypoperfusion.

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POTS may be a cause of chronic fatiguesyndrome in patients that exhibit signs oforthostatic intolerance. Treating POTS will

greatly improve or even eliminate disablingfatigue for these patients. Some patientswith fibromyalgia complain of

dysautonomia-related symptoms. Treatingthese patients for POTS will often improvemyofascial and neuropathic pain.

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Autonomic dysfunction is most likelyresponsible for irritable bowel syndrome inmany patients as well. Patients with

Ehlers-Danlos syndrome, often developPOTS as a secondary condition. SomePOTS patients experience symptoms

associated with Restless Leg Syndrome,or RLS. Treating POTS should also relieveRLS symptoms in these patients.

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Causes

The causes of POTS are not fully known. Most patients develop symptoms in their teenage years during aperiod of rapid growth and see gradual improvement into their mid-twenties. Others develop POTS after aviral or bacterial infection such as mononucleosis or pneumonia. Some patients develop symptoms afterexperiencing some sort of trauma such as a car accident or injury. Women can also develop POTS duringor after pregnancy. These patients generally have a poorer prognosis.

In one large test, 12.5% of 152 patients with POTS reported a family history of orthostatic intolerance, suggestingthat there is a genetic inheritance associated with POTS.

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So far no one has provided an explanation for POTS whichis applicable to all sufferers, however there are many

theories

Alpha-receptor dysfunction may be occurring in some POTS patients. Alpha-1receptors cause peripheral vasoconstriction when stimulated. Alpha-1 receptorsupersensitivity may be causing dysautonomia in some patients.

Beta-receptor supersensitivity may occur with hyperadrenergic states in somepeople with POTS.

Hyperdopaminergic states may be the underlying problem for some people withorthostatic intolerance. Some patients have been found to have a significant increasein upright dopamine levels. Free plasma norepinephrine also tends to be higher inthese patients.

Reduced venous return is one of the main mechanisms that causes POTSsymptoms. Venous return can be reduced due to conditions such as low plasmavolume (hypovolemia), venous pooling and denervation. A hyperadrenergic state may

result as the body attempts to compensate for these abnormalities. Sympathetic Overactivityis observed in many POTS patients. The sympathetic

overactivity can be secondary to a number of factors, some of which may beperipheral denervation, venous pooling, or end-organ dysfunction. Sympatheticunderactivty can also occur in some forms of orthostatic intolerance, such as pureautonomic failure.

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Diagnosis

POTS can be difficult to diagnose. A routine physical examinationand standard blood tests will not indicate POTS. A tilt table test isvital to diagnosing POTS, although all symptoms must beconsidered before a final diagnosis is made. Tests to rule outAddison's Disease, pheochromocytoma, electrolyte imbalance,

Lyme Disease, Celiac Disease, and various food allergies areusually performed.A blood test may be performed to verifyabnormally high levels of norepinephrine present in some POTSpatients.

Between 75 and 80 percent of POTS patients are female and of the

menstruating age. Most male patients develop POTS in their early tomid-teens during a growth spurt or following a viral or bacterialinfection. Some women also develop POTS symptoms during orafter pregnancy.

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Prognosis

Most POTS patients will see symptom improvement over the courseof several years. Those who develop POTS in their early to midteens during a period of rapid growth will most likely see completesymptom resolution by their mid twenties. Patients with post-viralPOTS will also usually improve greatly or see a full symptom

resolution. Adults who develop POTS, especially women during orafter pregnancy, usually see milder improvement and can beplagued with their condition for life. Rarely, a teenager who developsPOTS will gradually worsen overtime and have lifelong symptoms.Patients with secondary POTS as a consequence of Ehlers-Danlos

Syndrome will also usually struggle with symptoms for life. Recovered individuals do complain of occasional, non-debilitating

recurrence of symptoms associated with autonomic dysfunctionincluding dizzy spells, lightheadedness, flushing, transient syncope,and symptoms of irritable bowel syndrome.

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Treatment

Most patients will respond to some form oftreatment. Lifestyle changes, particularlydrinking extra water and avoiding trigger

situations such as standing still or gettinghot, are necessary for all patients. Somepatients also benefit from the addition of

other treatments, such as certainmedications.

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Dietary changes

Drinking more water improves symptoms for nearly all patients. Most patients areencouraged to drink at least 64 ounces (two liters) of water or other fluids each day.

Alcohol has been shown to drastically exacerbate all types of orthostatic intolerancedue to its vasodilation and dehydration properties. In addition to its adverse effects, itinteracts unfavorably with many of the medications prescribed to POTS patients.

Eating frequent, small meals can reduce gastrointestinal symptoms associated withPOTS by requiring the diversion of less blood to the abdomen.

Increasing salt intake, by adding salt to food, taking salt tablets, or drinking sportsdrinks and other electrolyte solutions, is a treatment used for many people withPOTS; however, salt is not recommended for all patients. Increasing salt is aneffective way to raise blood pressure in many patients with orthostatic hypotension byhelping the body retain water and thereby expand blood volume. Different physicians

recommend different amounts of sodium to their patients. Diets high in carbohydrates have been connected to impaired vasoconstrictive action.

Eating foods with lower carbohydrate levels can mildly improve POTS symptoms.

Caffeine helps some POTS patients due to its stimulative effects; however, otherpatients report a worsening of symptoms with caffeine intake.

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Physical therapy and exercise

POTS symptoms can be worsened by postural asymmetries, restrictions inmobility, and areas of adverse mechanical tension in the nervous system.These physical abnormalities can be relieved with gentle manual therapiesincluding neural mobilization (or neural tension work), myofascial release,and cranio-sacral therapy.

Exercise is very important for maintaining muscle strength and avoidingdeconditioning. Though many POTS patients report difficulty exercising,some form of exercise is essential to controlling symptoms and eventually,improving the condition.

Aerobic exercise performed for 20 minutes a day, three times a week, issometimes recommended for patients who can tolerate it.

Wearing ankle weights compels the leg muscles to work harder, therebyforcing pooling blood back into the upper body. It is especially helpful to putthe weights on before getting out of bed in the morning. Ankle weightsshould not be worn continuously, as the body will then adjust to the extraweight and they will no longer be effective. Ankle weights should be used

with caution, as they can possibly interfere with one's normal gait which cancause injury.

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Medications

Several classes of drugs often provide symptom control and relieffor POTS patients. Treatments must be carefully tested due tomedication sensitivity often associated with POTS patients, andeach patient will respond to different therapies in different ways.

The first line of treatment for POTS is usually fludrocortisone, orFlorinef, a corticosteroid used to increase sodium retention and thusincrease blood volume and blood pressure. An increase in sodiumand water intake must coincide with fludrocortisone therapy foreffective treatment.

Dietary increases in sodium and sodium supplements are oftenused. Gatorade is also effective in providing both sodium and fluid

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Beta blockers such as atenolol andpropanolol are often prescribed to treatPOTS. These medications work by

blocking the effects of epinephrine andnorepinephrine released by the autonomicnervous system. Beta blockers also

reduce sympathetic activity by blockingsympathetic impulses. For some patients,beta blockers increase POTS symptoms.

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Midodrine (Proamatine), is approved by the U.S. FDA to treat orthostatichypotension, a condition related to POTS. It is a stimulant that causesvasoconstriction and thereby increases blood pressure and allows moreblood to return to the upper parts of the body. Use of midodrine is oftendiscontinued due to intolerable side-effects, and it is known to cause supine

hypertension (high blood pressure when lying down). Antidepressants, especially selective serotonin reuptake inhibitors (SSRIs)

such as Prozac, Zoloft, Celexa, Lexapro, and Paxil, can be extremelyeffective in re-regulating the autonomic nervous system and raising bloodpressure. Some studies indicate that serotonin-norepinephrine reuptakeinhibitors (SNRIs) such as Effexor and Cymbalta are even more effective.

Tricyclic antidepressants, tetracyclic antidepressants, and monoamineoxidase inhibitors are also occasionally, but rarely, prescribed. Acombination of two antidepressants, usually an SSRI or SNRI withWellbutrin or Remeron, is also shown to be very effective.

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Medications used to treat ADD and ADHD such asRitalin and Adderall are used to balance dopaminelevels, increase vasoconstriction, and increase bloodpressure.

In the UK Ivabradine has been used to treat patientswith POTS symptoms with good effect. Ivabradine actsby reducing the heart rate in a mechanism different frombeta blockers and calcium channel blockers, two

commonly prescribed antianginal drugs. It is classified asa cardiotonic agent.

Anti-anxiety medications, such as Xanax, Ativan, andKlonopin, can be used to combat imbalances of

adrenaline usually seen with POTS patients.

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Angiotensin converting enzyme inhibitors, or ACE inhibitors, areused to increase vasoconstriction, cardiac output, and sodium andwater retention. Clonidine can work in patients with reducedsympathetic activity. Ironically an anti-hypertensive drug, Clonidinepromotes production and release of epinephrine and

norepinephrine. Disopyramide, or Norpace, is an antiarrhythmicmedication that inhibits the release of epinephrine andnorepinephrine. Erythropoietin, used to treat anemia via intravenousinfusion, is very effective at increasing blood volume. It is seldomused, however, due to the dangers of increasing the hematocrit, the

inconvenience of intravenous infusion, and its prohibitivelyexpensive cost. Pregabalin, or Lyrica, an anticonvulsant drug, hasbeen shown to be especially effective in treating neuropathic painassociated with POTS. In fact, Lyrica is currently the onlyprescription drug approved by the FDA to treat fibromyalgia. Some

POTS patients also report improvement in concentration and energywhile on Lyrica.

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Pseudoephedrine and phenylephrine, over the counterdecongestants, increase vasoconstriction by promoting the releaseof norepinephrine. Pyridostigmine, or Mestinon, inhibits thebreakdown of acetylcholine, promoting autonomic nervous systemactivity. It is especially effective in patients who exhibit symptoms of

excessive sympathetic activity. Theophylline, a drug used to treatrespiratory diseases such as COPD and asthma, is occasionallyprescribed at low doses for POTS patients. Theophylline increasescardiac output, increases blood pressure, and stimulatesepinephrine and norepinephrine production. Due to its very narrow

therapeutic index, Theophylline is known to cause a wide variety ofside-effects and even toxicity. Women who report a worsening ofsymptoms during menstruation will often use combined (containingboth estrogen and progestin) forms of hormonal contraception toprevent hormonal changes and an aggravation of their condition.

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External body pressure

Pressure garments can reduce symptoms associatedwith orthostatic intolerance by constricting bloodpressures with external body pressure.

Compression devices, such as abdominal binders and

compression stockings, help to reduce the amount ofpooling blood. Compression stockings should be at least30-40 mm Hg and will work best if they are waist high.Compression stockings should be fitted to achieve the

greatest benefit. Compressions suits (G-Suits) have also been used with

some good results

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Inappropriate sinus

tachycardia (IST)

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Definitie

Inappropriate sinus tachycardia (IST) is an uncommontype of cardiac arrhythmia, within the categoryof supraventricular tachycardia(SVT). The mechanismand primary etiology of Inappropriate sinus tachycardia

has not been fully elucidated. The mechanism of thearrhythmia primarily involves the Sinus Node and peri-nodal tissue and does not require the AV Node(Atrioventricular node) for maintenance. Treatments inthe form of pharmacological therapy or Catheter

ablation are available, although it is currently difficult totreat successfully.

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Diagnostic

Exclusion of all other causes of Sinus tachycardia Common forms of Supraventricular tachycardia (SVT)

must be excluded Normal P wave morphology

A resting Sinus tachycardia is usually (but not always)present Nocturnal dip in Heart rate Inappropriate Heart rate response on exertion Mean Heart rate in 24hrs >95bpm

Symptoms are documented to be due to tachycardia Hypotension is occasionally observed Syncope (fainting) is occasionally reported

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Tratament

IST has been treated both pharmacologically andinvasively, with varying degrees of success.

Some types of medication tried by cardiologists andother physicians include: Beta blockers, Calcium channel

blockers and Antiarrhythmic agents. Some SSRI drugsare also occasionally tried and also treatments morecommonly used to treat Postural orthostatic tachycardiasyndrome such as Fludrocortisone. This approach isvery much "trial-and-error". Patients with IST are often

intolerant to Beta blockers. A new selective sinus nodeinhibitor Ivabradine is also being used to treat IST

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Invasive treatments include

forms of Catheter ablation such as SinusNode Modification (selective ablation ofthe Sinus Node), Complete Sinus Node

Ablation (with associated implantation ofa Permanent Artificial pacemaker) and AVNode Ablation in very resistant cases

(creation of iatrogenic complete heartblock, necessitating implantation of aPermanent Artificial pacemaker).