Supraventricular Tachycardia


The most common form of supraventricular tachycardia is atrial fibrillation. Supraventricular tachycardia consists of accelerated heartbeat originating from the atria, and this can be deduced from the name of the condition (supraventricular means above the ventricles, that is the atria, tachy means fast and cardia means heart).

Supraventricular Tachycardia ecgIn supraventricular tachycardia, accelerated heartbeats are triggered by disorders of initiation or transmission of electrical impulses that cause the heart contractions. Usually, the heart rate during supraventricular tachycardia episodes are located between 150 and 200 beats per minute, occasionally more than 300 per minute.

After a period of time, the heart returns to the normal heart rate (from 60 to 100 beats per minute), spontaneously or by following the treatment. Other names synonymous with supraventricular tachycardia are: “paroxysmal supraventricular tachycardia” or “paroxysmal atrial tachycardia.”

Types of Supraventricular Tachycardia

In some cases increased heart rate is normal (for example: during exercise, fever, stress). This rapid heart rate, called sinus tachycardia, constitutes a normal response to physical or mental stress factors and is not considered pathological (abnormal).

Pathological forms of supraventricular tachycardia are:

  • Atrial fibrillation (the most common);

  • Supraventricular tachycardia with atrioventricular input, including The
    Wolf-Parkinson-White Syndrome.

Causes of Supraventricular Tachycardia

A common cause of supraventricular tachycardia is given by the existence of some abnormal electrical circuits on the heart, as it does in atrioventricular reentrant tachycardia and atrial tachycardia by entering and this happens frequently in individuals that have no other heart problems. Nobody knows the exact cause of this phenomenon. Some experts believe those reentrant tachycardias intra-atrial (especially in the case of Wolf-Parkinson-White syndrome) are inherited.

Other causes:

  • Overdose of some medications such as digoxin (Lanoxin or Lanoxicaps) or the theophylline bronchodilators (Brankodyl, Elixophilin, Sio-Bid, Sio-Philin or Teotard);

  • Other disease conditions such as chronic obstructive pulmonary disease, heart failure, pneumonia, or metabolic disorders.

Risk factors

Some risk factors related to lifestyle increases the chances of triggering an episode of supraventricular tachycardia, as is the case of consumption of excessive amounts of coffee, cigarettes or alcohol or using drugs, such as cocaine or methamphetamine (stimulants of the nervous system central). Moreover decongestant medications (used to treat colds) may contain substances that can induce tachycardia, as is the case oxymetazoline (for example Afrin) or pseudoephedrine (Sudafed, Actifed, etc.). Doctors recommend caution regarding the use of pharmaceutical products that can be purchased from pharmacies without a prescription, as many of them have in their content caffeine, ephedrine plant “ma hung” and other stimulants of the heart.

A special form of supraventricular tachycardia, multifocal atrial tachycardia (MAT) can be triggered by preexisting conditions such as chronic obstructive pulmonary disease, pneumonia, heart failure (impaired function of the heart) and pulmonary embolism (one or more of the pulmonary arteries clog and thus, the territory served by them will not be well vascularized and it will be necrosis, losing his position).

Because it has been hypothesized that Wolf-Parkinson-White syndrome may be inherited genetically, doctors recommend those who have close relatives suffering from this disease to consult a specialist to determine if there is an opportunity to further develop this rhythm disorder.

The consultation of a specialist

It is recommended that you quickly call the emergency service (112) in the following situations associated with rapid pulse:

  • Fainting or fainting imminent situation;

  • Shortness of breath;

  • Chest pain;

  • Symptoms of heart attack or stroke.

It will appeal to a heart specialist advice if the person will feel persistent palpitations and long-lasting or has frequent episodes with these features.

Supraventricular Tachycardia – Investigations

Because deciding of the type of treatment depends on the type of tachycardia applied to the patient is very important to establish an accurate diagnosis. Sometimes the diagnosis of supraventricular tachycardia can be established only through a routine medical examination, in conjunction with the establishment of personal history and the family history of the patient (what other diseases the patient had and his closest relatives) and by developing some simple investigations.

On physical examination it is useful to perform a carotid massage (massage gently in the neck area where the carotid artery’s route and this procedure should have the effect of decreasing the heart rate).

Investigations useful for monitoring the heart rate and determining the type of tachycardia that the patient has, are:

  • Electrocardiogram (ECG ) which records the electrical activity of the heart, if it succeeds in recording the ECG route while the patient suffers an episode of tachycardia can get extremely useful information;

  • Holter monitoring – it is a way to continuously recording the electrical activity of the heart, usually more than 24 hours, and this procedure is useful for patients whose symptoms are inconstant; There are many types of ambulatory monitoring;

  • Electrophysiological study – by introducing of flexible wires (that at the end had some recording electrodes) through veins (most commonly in the thighs) and push them gradually to the heart, it can directly record the electrical activity of the heart; This method can identify and locate the exact pathways of abnormal electrical impulses of driving; more can be achieved by catheter ablation (respectively the circuit interferes with radiofrequency waves) and can interrupt these pathological circuits;

  • The therapeutic diagnosis through the administration of certain medications during the episode of tachycardia and by tracking their effects can cause sometimes the type of tachycardia;

  • The diagnosis therapeutic through the administration of certain medications during the episode of tachycardia and by tracking their effects can cause sometimes the type of tachycardia.

After diagnosing the condition, it is useful to find the cause which determined the appearance. There are specific for certain types of investigations and tachycardia:

  • Determination of thyroid hormones (these hormones have an influence on the heart rate);

  • Determining the amount of blood electrolytes (for example: potassium and calcium influences heart rate and rhythm);

  • The chest radiography and pulmonary function testing can detect lung diseases.

Supraventricular Tachycardia Treatment – General things

Treating supraventricular tachycardia requires in case of:

  • Patient experiences dizziness, chest pain, syncope that are caused by rapid heart rate;

  • Rapid heart rate episodes are frequent or resolve spontaneously (without treatment fail).

Treatment of episodes of tachycardia recently installed (acute)

For this kind of disorder can initially try vagal maneuvers application (carotid massage, breath with the glottis closed, facial immersion in cold water compression eyeballs and coughing). These maneuvers available stimulate the vagus nerve plays an important role in lowering heart rate. These procedures should be performed on the advice and instructions given by the doctor.

In case of vagal maneuvers performed did not work, you can try the administration of some medications acting in short term, administered orally. They can help the patient to take the medication at home in case of tachycardia returns, without having to go to the emergency service at every opportunity.

If the heart rate is not ameliorating, then the patient should show up at the emergency room where he should be administered Adenosine or Verapamil, fast acting medications. Whether this measure does not work, then you can use that electrical cardioversion which by controlled administration of electric shocks can restore a normal heart rate.

Long-term treatment of recurrent tachycardia

In this form of tachycardia is recommended administration of medications either at need, or in every day, regardless of the presence of crises. Medications commonly used are beta-blockers, calcium channel blockers step, digoxin and other antiarrhythmic drugs. In individuals with frequent recurrences, these medications can reduce the number of seizures. However, such medication has often side effects.

Becomes more frequently to treat these patients using radiofrequency ablation that relies on blocking abnormal electrical circuit to the heart, and in this way to solve the problem and the patient will not be forced to take medication. However this maneuver is not without risks, including the development of some infections, bleeding and damages to the heart producing. The patient will have to make a decision based on careful evaluation of the two possibilities: either administration of medication for life, either risking an invasive procedure. Another constraint of the procedure is that it is not done only in a few medical centers that own medical equipment required (for example: Bucharest, Timis, Iasi, Tagu Mures).

Tachycardia treatment by reentry in the atrioventricular node

In this case you can opt for either medication taken daily or in time of crisis tachycardia either for radiofrequency ablation. If the patient has infrequent episodes of tachycardia that lasts a few hours and not accompanied by significant symptoms, you can choose to only take medicines in crisis. These are represented by antiarrhythmic medications such as propafenone, calcium channel blockers such as verapamil or beta-blockers, such as propranolol.

The doctor also may recommend taking daily calcium blockers, beta-blockers and / or digoxin if crises are common. If these medicines are not effective in stopping recurring crises of tachycardia, they can opt for taking antiarrhythmic medication.

In patients treated daily with medicines that crises are frequent and accompanied by significant symptoms can opt for catheter ablation. A recent study revealed that in 96 % of cases radiofrequency ablation fails to stop attacks of tachycardia reentry in the atrioventricular node. However, the procedure is not without risks and in rare cases, the arrhythmia returns which may require a second surgery ablation.

Treatment of atrial reentrant tachycardia

And in this type of tachycardia they can choose either daily treatment with medication or treatment only when the crisis appears, it depends on the frequency of this occurrence. Medications such as digoxin, beta-blockers and calcium channel blockers (verapamil and diltiazem) are often effective in stopping episodes of this kind of tachycardia.

However, there is a type of tachycardia with atrioventricular nodal reentrant, called Wolf-Parkinson-White syndrome in whom this type of treatment can induce the occurrence of extremely rapid heart rate, which may occur with the feeling of “heavy head “, fainting (syncope) and even death. Treatment of Wolff-Parkinson-White syndrome can be achieved with antiarrhythmic medication such as Propafenone, which decreases conduction velocity of electrical impulses in the accessory pathway.

Radiofrequency ablation is frequently recommended for patients with this syndrome, especially in those with severe symptoms or who develop atrial fibrillation or atrial flutter (very common is due to contraction of the atria). Ablation can cup about 95% of Wolf-Parkinson-White syndrome. There is a low risk (5%) that this disease will relapse (reoccur), even with a successful ablation. But almost always a second ablation will be able to permanently occupy the arrhythmia.

Medical Treatment

In the treatment of symptomatic supraventricular tachycardia can be used medications.

Medication options

For severe symptoms (chest pain, shortness of breath, feelings of presyncope – fainting) can be administered fast-acting antiarrhythmic drugs by health care specialists equipped with the equipment necessary to monitor heart rate. This category of medications includes:

  • Adenosine;

  • Calcium channel blockers (particularly verapamil and diltiazem);

  • Beta-blockers (especially Propranolol, metoprolol and esmolol).

Long-term medication may also be useful for countering the appearance and treatment of recurrent episodes of tachycardia. In this category are:

  • Beta-blockers;

  • Calcium channel blockers;

  • Digoxin;

  • Other antiarrhythmic drugs.

To remember!

All of the above drugs have side effects.

Surgical Treatment

Open heart surgery for this type of condition is made ​​rarely and only where other forms of treatment (medication or catheter ablation) didn’t show any result, are contraindicated or inaccessible. If surgery is done for another concomitant condition, surgical ablation of the electrical circuit in the same time can be achieved.

Other Treatments

Electrical cardioversion (external electric shock administration) may be necessary in patients with supraventricular tachycardia that does not respond to vagal maneuvers or fast-acting antiarrhythmic medication and the symptoms are severe. Electric conversion is used only in emergencies. If the patient is conscious, will be administered pain medication and anesthesia (for patient causes drowsiness) during the maneuver.

Electrophysiological study (measuring currents in the heart through direct measurements through electrodes inserted into the cardiac cavities) can identify the accessory pathway causing the arrhythmia in question and can perform radiofrequency ablation (destruction of those pathways).

A recent study for catheter ablation demonstrated that the procedure has a very low risk and it is highly effective for patients with severe symptoms and frequent supraventricular tachycardia reentry in the atrioventricular node. It also reduces costs, as compared to patients receiving long-term medication. The study demonstrated that the procedure can be applied to those with mild or moderate symptoms.

But yet the procedure is not without risks (infection, bleeding, damages to the heart which then may require implantation of a pacemaker), although they are rare. The patient will balance the prospect of medical treatment for life, with the prospect of invasive interventions. There is also a risk (however small) that tachycardia will reoccur, requiring a second surgery. In addition through the catheter ablation is a procedure available everywhere, it being made only in medical centers equipped with the necessary equipment and qualified personnel.

Supraventricular Tachycardia – Prophylaxis

These episodes of tachycardia can be prevented by avoiding toxins that stimulate the heart rate, such as coffee, nicotine and certain medications (nasal decongestants), drugs (methamphetamine and cocaine), excessive alcohol, lack of sleep or excessive consumption of food from a single table. If the heart rate is increased continuously, can be administered long-term medications (beta-blockers) to prevent their occurrence.

The lifestyle of those with tachycardia

It is indicated to monitor the heart rate at home and addressing measures to decrease heart rate when tachycardia occurs. One can try writing a “diary” in which to record the symptomatology and the heart rate during each tachycardia.

The patient will be instructed how to check their pulse during episodes and record the values ​​in the “diary “. The patient must realize that during episodes of symptomatic tachycardia is difficult to measure pulse rate and counted accurately. By writing the “diary” mentioned above, the patient can identify the factors that cause tachycardia.

It is useful to avoid caffeine, nicotine and drugs (such as ecstasy, cocaine or methamphetamine). For highly sensitive individuals even decaffeinated coffee and tea can cause episodes of supraventricular tachycardia. Avoid also nasal decongestants such as oxymetazoline (for example Afrin) pseudoephedrine (for example: Sudafed, Actifed, etc.) and the products used as supplements for weight loss (many contain caffeine, ephedrine, ephedra, ma huang plant or other stimulants). Patient will be instructed how to perform at home vagal maneuvers (coughing, exhale with the glottis closed, facial immersion in cold water, etc.) in order to reduce heart rates.

Evolution

The symptomatology in reentry tachycardia in the atrioventricular node, including Wolff-Parkinson-White syndrome, begins in the teenage years and young adult. WPW syndrome can trigger episodes of life-threatening heart rhythms such as ventricular fibrillation, although this phenomenon happens very rarely. It is therefore advisable for the patient to inform medical personnel on his situation, in the event of a crisis.

Reentry tachycardia in atrial node usually starts somewhere in the period between adolescence and middle age. If a patient develops an episode of supraventricular tachycardia, is expected to repeat this phenomenon. These arrhythmias are resolved spontaneously by simple vagal maneuvers, but also may require daily medication, if they persist. Medication is represented by beta-blockers, calcium channel blockers or digoxin. It may also be necessary to administer antiarrhythmic drugs or radiofrequency ablation performance.

If tachycardia occurs in a patient with known coronary artery disease (blood vessels that supply the heart) the heart may not receive enough blood compared to needs while elevated heart beat with increased frequency. In this case the heart is deprived of oxygen it is possible for a heart attack (myocardial infarction).


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1 Response

  1. March 9, 2015

    […] tissue between the atria and ventricles which is frequently associated with the appearance of supraventricular tachycardia. It requires activation of the ventricles before the normal contraction  (pre-excitation) through […]

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