Atrial tachycardia is a constantly relapsing form. Rapid heartbeat of the atrial type: features and treatment. How is paroxysmal atrial tachycardia treated?


Today we invite you to talk about what atrial tachycardia is. In addition, we will examine many issues: classification, causes, symptoms, diagnosis, treatment, and so on.

Before we get to the heart of the matter, I would like to note the following fact: AT (atrial tachycardia) is observed in people with heart problems, but often this ailment is noticed in absolutely healthy people.

Despite the fact that in most cases the disease is mild, unpleasant symptoms require drug therapy(we will also talk about this later).

As the name implies (atrial tachycardia), the source of the disease is the atrium. The causes of the disease are numerous: from smoking and excess weight to surgery on the atrium and chronic lung diseases and of cardio-vascular system.

What it is?

Let's start with the fact that atrial tachycardia has a focus (a small area where the disease occurs). It is in the hearth that stimulation of faster heart contractions occurs by generating electrical impulses. This causes a person's heart rate to increase.

As a rule, the generation of these impulses is not constant; they do not occur so often. In this case, the disease is called “paroxysmal atrial tachycardia”. However, there are cases when this happens continuously over several days or months. It is worth noting that there may be more than one focus, which is seen in older people or those suffering from heart failure.

In addition, we will note atrial tachycardia with AV block, this is quite serious illness, which are a type of arrhythmia. Localization - atrium. The disease is very for a long time may not manifest itself in any way, but then its manifestations become quite frequent and stable. Heart disease is nothing to joke about; for example, this problem can cause instant death or syncope. Let us immediately clarify the last term - short-term. Recognizing an attack is quite simple - the heart begins to beat faster, from 140 to 190 beats per minute.

Constant manifestations of increased heart muscle activity are a serious reason to visit a cardiologist, because the disease is depleting your heart.

Kinds

There are three types of atrial tachycardia:

  • With a blockade.
  • Monofocal (from 100 to 250 contractions of the heart muscle per minute with a constant rhythm).
  • Multifocal (distinctive feature - irregular rhythm).

In addition, it is worth noting that atrial tachycardia can have one or more sources. Based on this, all types can be divided:

  • to monofocal (one focus);
  • multifocal (several foci).

Classification

Now let's give a classification of this disease on several grounds. The first is the localization of the area where pulses are generated. There are three types in total:

  • sinoatrial reciprocal (localization - sinoatrial area);
  • reciprocal (localization - atrial myocardium);
  • polymorphic atrial tachycardia (may have one or more foci).

The next sign of classification is the course of the disease. For greater convenience, we have provided a table.

The last sign of classification is the mechanism influencing the appearance of the impulse. Just as in the previous version, a table is provided for convenience.

Variety Cause
Reciprocal

There could be several reasons:

  • presence of cardiovascular disease;
  • incorrect selection of medications;
  • incorrect choice of treatment procedures.

In this case, the heart rate varies between 90-120 beats per minute
Automatic

Often seen in young people. The cause of automatic atrial tachycardia is physical overexertion. This type does not require treatment
Trigger

Here we see the opposite picture. Trigger tachycardia is more common in older people. The reasons may be:

  • physical stress;
  • taking cardiac glycosides
Polytopic

This variety may appear as a result of a history of serious illness lungs. In addition, polytopic tachycardia may accompany a disease called heart failure.

Causes

Let's try to understand the causes of atrial tachycardia. This disease can occur for many reasons, including heart disease, valve abnormalities, heart damage or weakening of the heart. The reasons for the latter factor may be transferred heart attack or inflammation.

In addition, drug addicts and alcoholics, people with metabolic disorders are at risk. The latter is possible if activity is increased thyroid gland or adrenal glands.

It’s worth mentioning right away: in most patients the true cause of the disease has never been established. If the doctor suspects atrial tachycardia, he will definitely prescribe several tests:

  • blood analysis;
  • electrocardiogram of the heart (simpler - ECG);
  • electrophysical research.

All this is necessary to find out the cause of tachycardia. But you should prepare yourself in advance for the fact that the true origins of the disease will not be established for sure. This is especially true for older people. Attacks of atrial tachycardia are a common occurrence in them. So this is considered to be the norm.

So, let's list a few more causes of atrial tachycardia:

Symptoms

Symptoms include:

  • increased contraction of the heart muscle;
  • shortness of breath;
  • dizziness;
  • chest pain;
  • the appearance of feelings of anxiety and fear;
  • darkening of the eyes;
  • the appearance of a feeling of lack of air.

Let us immediately note that the symptoms are not the same for everyone; some may feel the entire above-mentioned complex, while others will not notice how the attack passes. Most people have no symptoms at all or only noticeable palpitations.

It is also worth paying attention to the fact that young people are more likely to notice signs than older people, since in the latter case, an increase in contractions of the heart muscle, as a rule, goes unnoticed.

Diagnostics

If you notice signs of atrial tachycardia, you should contact a cardiologist. The doctor must refer you for a number of studies:

But anyway the only way diagnosing the disease - conducting an ECG at the time the attack begins. If you describe your symptoms to your doctor, he or she may perform a Holter ECG (monitoring the patient's heart function over 24 or 48 hours). If this option is not possible, then the cardiologist can provoke an attack during the electrophysiological study procedure.

Differential diagnosis

You can see what atrial tachycardia looks like on an ECG in the photograph in this section of the article. Distinctive features:

  • correct rhythm;
  • cardiopalmus;
  • R-R interval not the same;
  • the P wave is either negative or at the same level with T.

IN mandatory must be excluded:

  • sinus tachycardia (features: heart rate up to 160 per minute, gradual development and decline);
  • sinus-atrial paroxysmal tachycardia (features: P configuration is normal, mild course, relieved by antiarrhythmic drugs).

Is the disease dangerous?

Before we move on to treating atrial tachycardia, we will find out whether it is life-threatening. Despite possible unpleasant symptoms of this disease, the disease does not pose a serious threat to life.

If you do not constantly experience rapid heartbeat, then the heart muscle can easily cope with attacks. It is also important to note that these same attacks do not lead to any other heart problems. The exception is the presence of complications (for example, angina). As mentioned earlier, the presence of rare attacks is not dangerous, but what to do if the heart is forced to work hard for a long period of time (days or even weeks)? Constant acceleration of the heart muscle leads to its weakening. To avoid this, treatment is necessary.

There is no risk of blood clots or stroke, so there is no need to take blood thinners (anticoagulants). The doctor's only recommendation is to take Aspirin or stronger analogues, such as Warfarin. There is a need to take the latter drug when the patient has other heart disorders (for example, atrial fibrillation, which is characterized by an irregular heart rhythm).

Treatment

Treatment is selected individually by an experienced specialist. We can say that the selection of medications is done by trial and error. As a rule, atrial tachycardia is asymptomatic, so treatment is not necessary.

Drug therapy or catheteral ablation is necessary in two cases:

Atrial tachycardia with AV block requires urgent discontinuation of glycosides (if the patient is taking them). A solution of potassium chloride, or rather intravenous, helps to stop an attack drip infusion. In addition, phenytoin is used.

Predictions and prevention

Prevention measures include:

  • active lifestyle;
  • proper nutrition;
  • healthy sleep(at least 8 hours);
  • maintaining a healthy lifestyle (giving up cigarettes, alcohol, drugs, etc.).

It is necessary to avoid overwork and stressful situations. The prognosis for this disease is favorable. If you follow your doctor's recommendations, atrial tachycardia does not pose a serious danger to human life.

Fedorov Leonid Grigorievich

Why does the disease occur?

The development of such rhythm disturbances occurs in at a young age without the presence of heart pathologies, due to strong physical activity.


In this case, attacks occur suddenly and disappear without treatment. People suffer from them from hypertensive type. With this diagnosis, unstable atrial tachycardia is most often detected.

In old age, atrial tachycardia develops with organic damage to the heart, lung pathologies, and age-related changes in the body.

In most cases the problem is due to:

  • inflammatory processes in heart;
  • post-infarction changes;
  • stenosis or insufficiency mitral valve;
  • cardiomyopathies;
  • hypertrophic changes in the left ventricle as a result of hypertension.

With such pathologies, normal tissues are replaced by scar tissue or hypertrophied ones, and an obstacle appears in the path of impulses.

Not only cardiac pathologies can lead to such problems. Tachycardia often accompanies obstructive processes in the bronchopulmonary system. These problems contribute to the formation pulmonary heart, accompanied by where the development of the ectopic rhythm occurs.

Atrial paroxysmal tachycardia It is recorded on the ECG in people experiencing a fever, poisoned by alcoholic beverages or narcotic substances.

Atrial tachycardia is one of the types of arrhythmic disorders when an ectopic focus is formed in the supraventricular zone. Pathological electrical impulses that further stimulate the heart muscle can be generated by one or more foci formed in the atria.

Several lesions usually appear in patients with other cardiac pathologies, which often occurs in old age.

With multiple foci, excitation waves circulate around large areas of the atria, which often causes them to flutter. In pathology, the main signs on the ECG are P waves separated by an isoline, which differs from the diagnosis of atrial flutter.

  • All information on the site is for informational purposes only and is NOT a guide to action!
  • Can give you an ACCURATE DIAGNOSIS only DOCTOR!
  • We kindly ask you NOT to self-medicate, but make an appointment with a specialist!
  • Health to you and your loved ones!

Single-focal atrial tachycardia develops with 1 arrhythmogenic zone, multifocal atrial tachycardia can have 3 or more zones. AT is a type of supraventricular tachycardia, usually leading to short-term or prolonged syncope.

In 70% of cases, patients develop right atrial tachycardia, less often left atrial tachycardia. People with chronic diseases heart, bronchi and lungs. Typically, attacks of atrial tachycardia occur from time to time, but can drag on for days or weeks.

At pathological condition the frequency of contractions of the heart muscle can reach 140–240 beats per minute, but on average this figure is 160–190.

Classification

Depending on the localization of the site of formation of electrical impulses, atrial pathology can be:

Depending on the mechanism of generation of pathological impulses, atrial tachycardias are divided into:

Reciprocal
  • caused by pathologies of the heart muscle that arise against the background atrial fibrillation, sometimes atrial flutter;
  • the frequency of muscle contractions reaches 90–120 beats;
  • In this form of pathology, even beta blockers are considered ineffective; normal heart rhythm can be restored only by radiofrequency ablation.
Automatic The pathology most often occurs in adolescents and gradually develops into chronic form. The heart rate increases after the onset of heart pain during exercise.
Trigger Tachycardia is more common in older people, especially attacks often occur after intoxication while taking glycosides, when sympathetic tone increases. Depolarization and physical activity can also cause pathology.
Polytopic Atrial tachycardia is caused by lung diseases and, in this case, the attack can turn into, and the contraction frequency on average ranges from 100 to 125 beats.

Causes

The main reasons that cause attacks of atrial tachycardia are heart disease and the factors that primarily affect it.

Pathology can occur against the background of:

  • high blood pressure;
  • heart failure;
  • various;
  • chronic diseases of the bronchi and lungs;
  • heart surgery;
  • intoxication after alcohol, other toxic substances;
  • thyroid diseases;
  • metabolic disorders;
  • excess body weight;
  • problems with blood circulation;
  • increased activity thyroid gland and adrenal glands.

Often attacks are caused by excessive intake of glycosides and antiarrhythmic drugs, especially Novocainamide, which is typical for the elderly.

Stomach diseases can also cause short-term paroxysms of PT. But very often it is not possible to establish a clear cause of the pathology. For older people, short-term attacks are considered normal.

Symptoms of atrial tachycardia

Clinical signs of PT completely coincide with arrhythmic disorders and manifest themselves:

  • general malaise;
  • shortness of breath, feeling of lack of air;
  • dizziness and darkening of the eyes;
  • chest pain;
  • an attack of rapid heartbeat;
  • anxiety and fear.

Symptoms can vary greatly depending on age; in some patients, apart from palpitations, there are no other manifestations of atrial tachycardia.

For example, at a younger age, when a person has a healthy heart, an attack of arrhythmia is more noticeable. In older people, short-term increases in heart rate often go unnoticed.

Diagnostics

Equally important is the analysis of thyroid and adrenal hormones.

To determine focal and multifocal PT, the waves on the electrocardiogram are deciphered.

Most often, when one lesion is localized, the following is detected:

  • a P wave different in shape from the sinus wave, which precedes the QRS complex;
  • presumably arrhythmogenic area indicated by P waves in 12 leads.

Atrial tachycardia on the ECG is characterized by:

  • positive P waves in leads 2, 3 and avF, indicating PT, with the focus located close to sinus node;
  • negative P waves in leads 2, 3 and avF, indicating AT, with the focus located close to the coronary sinus and AB junction;
  • positive polarity of P waves in leads 1 and avL in right atrial and negative in left atrial AT;
  • positive M-shaped waves of the P wave in lead V1, when the source of pathological impulses is in the left atrium;
  • often superimposed P waves on T waves, preceding the QRS complex at a heart rate of 150–200 beats;
  • PQ interval prolonged compared to sinus rhythm.

Multifocal atrial tachycardia on the ECG is characterized by P waves that continuously change in frequency and configuration.

With three ectopic foci, 3 morphological variants of P waves will be observed, which are separated from each other by isolines

Differential

Atrial tachycardia without eliminating the arrhythmic disorder allows for pathology.

To provoke temporarily worsening AB conduction, use:

  • vagal tests;
  • intravenous administration of Isoptin or ATP.

When the mechanism of impulse development is automatic, the activity of the pathological focus and a gradual increase in the rhythm of contractions will be observed.

The contraction frequency decreases before the cessation of tachycardia, when the activity of the ectopic focus decreases. These phenomena of “warming up” and “cooling” the arrhythmogenic focus are unusual for tachycardias occurring in a reciprocal type, which are the most common among supraventricular pathologies.

The polarity of the P waves is an important differential indicator. The positive nature of the P waves in leads 2, 3 and avF is characteristic of atrial tachycardia. If negative P waves are observed in these leads, then other signs identified on the ECG are needed to confirm atrial tachycardia.

Treatment

PT does not pose a particular danger to the patient’s health; therapy is necessary for accompanying negative symptoms.

Very often, pathology is discovered by chance during examination using an ECG.

But if the patient’s quality of life gradually decreases due to unpleasant clinical signs, the frequency of contractions of the heart muscle during attacks is constantly increasing, and over time the size of the heart cavities may increase. Therefore, after diagnosis, the doctor prescribes radiofrequency ablation.

and blockers calcium channels
  • with their help, the ventricular rhythm is controlled during attacks of AT;
  • they are capable of delaying electrical conductivity in the atrioventricular node;
  • drugs can be used orally or intravenously if necessary;
  • with their help it is also possible to prevent attacks and relieve the severity of their course.
Antiarrhythmic drugs
  • help maintain sinus heart rhythm by acting on the heart muscle and slowing electrical conduction;
  • many patients use antiarrhythmics to stop atrial tachycardia;
  • in some cases, they contribute to the development of other cardiac pathologies, posing a threat to health, so the doctor changes the patient’s treatment tactics.
Catheter ablation method
  • is able to relieve the patient from tachycardia and accompanying symptoms in 90% of cases;
  • the procedure is performed under anesthesia, although it does not require opening the chest;
  • Using a special catheter, a high-frequency current is supplied to the heart, destroying the ectopic focus and disrupting conduction along the His bundle.

Why is it dangerous?

Typically, the heart muscle copes with attacks of atrial tachycardia, rarely causing complications. Only if the attacks last for several days does this weaken the heart muscle.

To prevent other rhythm disturbances, especially atrial fibrillation, the doctor recommends treatment.

Forecast

Atrial tachycardia is considered an isolated pathology; the development of the disease can be controlled through a healthy lifestyle, eliminating alcohol and nicotine addiction, improving the quality of sleep, and avoiding stress.

The prognosis is quite favorable; the pathology does not always require treatment, despite the fact that short-term attacks can be repeated.

The concern should be caused by prolonged attacks that occur over several months or years, when the patient has not sought help or received treatment. In this case, organic disorders of the atrial myocardium may appear.

Also, if prolonged episodes of atrial tachycardia occur, when treatment is not started on time, it is more difficult to restore normal sinus rhythm in the future.

If the arrhythmogenic focus is located in the atrium of the myocardium, then atrial tachycardia develops. Pathology occurs regardless of the presence of other heart diseases in the patient. If the attacks are short-lived, then treatment is not carried out. If your heart rate increases for a long time, you should contact medical care. Otherwise, the heart muscle is depleted.

What is the cause of the pathology?

Short-term attacks of tachycardia can occur against the background of stomach diseases.

For people in the older age group, a periodic increase in heart rate is considered normal occurrence. The disorder may be due to misuse row medicines. Pathology is often detected in people who are obese. In addition, the following factors influence the occurrence of atrial tachycardia:

  • myocarditis;
  • hypertension;
  • heart failure;
  • metabolic disease;
  • heart disease;
  • pathologies of the endocrine system;
  • previous operations;
  • chronic lung diseases;
  • intoxication;
  • physical fatigue;
  • circulatory disorders;
  • consumption of alcohol and drugs.

How to recognize the disease: main signs

Against the background of this condition, the patient may complain of darkening in the eyes.

As the pathology develops, electrical impulses stimulating the heart are generated in the atria. In older people, several lesions are detected at once. According to statistics, in 70% of patients, tachycardia occurs due to increased activity of the right atrium; in other cases, a left atrial disorder is diagnosed. Often, attacks occur periodically, but prolonged tachycardia is possible, in which increased heart rate is observed for several days or weeks. Heart rate can reach 140–240 beats/min. Average is 160–190 beats/min.

Symptoms of atrial tachycardia:

  • general weakness;
  • dyspnea;
  • dizziness;
  • blurred vision, darkening of the eyes;
  • pain in the chest area;
  • feeling of fear and anxiety.

What kind of examination is carried out?

There are several types of pathology. Thus, paroxysmal atrial tachycardia occurs suddenly and has a regular rhythm. In non-paroxysmal disorders, prolonged attacks or frequently recurring periods of malaise occur. In any case, if you experience symptoms indicating a problem with the heart, you need to undergo an examination. The following diagnostic methods can detect atrial tachycardia:

Echocardiography will help identify cardiac pathology in a person.

  • Clinical analysis of urine and blood. Detects the presence of adrenaline breakdown products in the body, establishes the level of hemoglobin and the presence of inflammation, and excludes a number of blood diseases.
  • ECG. Detects features of the heart. Main sign atrial tachycardia - P waves separated by an isoline.
  • EchoCG. Reveals the condition of the heart muscle and the level of functionality of the valves.
  • Ultrasound of the myocardium. Indicates those present chronic diseases which may cause tachycardia.
  • Blood test for hormones. The level of functioning of the thyroid gland and adrenal glands is determined.

Differential diagnosis

Atrial tachycardia is often discovered incidentally during a routine ECG. To detect a violation in a timely manner, you need to undergo regular medical examinations.


It is important to distinguish pathology from atrial flutter.

Before prescribing treatment to a patient, the doctor differentiates the examination results obtained with similar indicators characteristic of other diseases. If the heart rate exceeds 220 beats/min, this indicates atrial flutter. When an isoelectric line appears on the ECG between the P waves on II, III and aVF, they speak of atrial tachycardia. A comparison is made with sinus and sinus-atrial paroxysmal tachycardia. In the first case, the heart rate is 160 beats/min. with gradual development and subsidence. In the second, the P waves have a normal configuration, there is a mild course and relief of the pathology with the help of antiarrhythmic drugs.

What treatment is prescribed?

In most cases, the pathology does not require special therapy. If the heart rate increases and the patient's quality of life due to malfunction the heart is getting worse, the course is being selected drug treatment. The following groups of drugs are prescribed:

  • Beta blockers and calcium channel blockers. They control ventricular rhythm and delay electrical conduction. They improve the condition during attacks and prevent their occurrence.
  • Antiarrhythmic drugs. Maintains sinus rhythm and slows electrical conductivity. They are used with caution, as they can provoke the development of other heart diseases.


110 years ago, the French physician L. Bouveret (Bouveret Y., 1852 -1929) first described one of the forms of supraventricular paroxysmal tachycardia, which he called “essential paroxysmal tachycardia.” Together with the monograph of the German clinician A. Hoffman, published in 1900, Bouveret’s work should be considered the beginning of the scientific study of supraventricular tachycardias.

Over the more than century-long period that has passed since the description of tachycardia by Bouveret-Hoffman, significant progress has been made both in uncovering the electrophysiological mechanisms of supraventricular tachycardias and in dividing them into numerous forms.

This report is devoted to the analysis of truly atrial forms of atrial tachycardia, many of which were previously mixed with atrioventricular paroxysmal tachycardias (PT). First of all, we cannot help but mention some new diagnostic problems that have arisen in our time.

Firstly, the description of sinus node reciprocal AT, which is based on the re-entry mechanism in the SA node, calls into question such generally accepted concepts as “ectopy” and “heterotopy”, since the SA node is a nomotopic and not an ectopic pacemaker (nomotopic pacemaker). Secondly, the discovery of triggered focal atrial tachycardias with a period of “warm up” at their beginning noticeably weakens the well-known rule, which states that an attack of tachycardia always begins acutely, with one or two beats or jolts in the region of the heart, felt by patients (about Bouveret wrote about such “blows”). Thirdly, the stability of some forms of atrial tachycardia for weeks, months, even years gives the terms “paroxysm” or “attack” a conventionality. Finally, fourthly, difficulties are still encountered in distinguishing between “slow” atrial tachycardias and accelerated atrial rhythms. The accepted dividing limit of 100 pulses per minute cannot always be unconditionally accepted, for example, in conditions of digitalis intoxication.

After this necessary, in our opinion, introduction, we move on to the classification of atrial tachycardias. This classification, in addition to literature data, is based on the rich experience of the Department of Cardiology of the St. Petersburg MAPO. We are referring to the results of more than 40 intracardiac studies of atrial tachycardias carried out at the department by Yu.M. Grishkin; 36 observations made by P.T. Butaev using the method of transesophageal ECG recording and transesophageal cardiac pacing, and finally, more than 50 cases of atrial tachycardia, carefully analyzed by ECG - more than 130 observations in total.

As shown in table. 1, the classification presents 6 main classes (types) of atrial tachycardia.

Table 1.

Clinical and electrophysiological classification of atrial tachycardias

I. Sinus node re-entry paroxysmal tachycardia:
1. With sick sinus syndrome (SSNS).
2. Without SSSU.
II. Atrial re-entry tachycardia:
1. Paroxysmal (including the Ogawa form (1977) - re-entry in the interatrial bundle of Bachmann).
2. Constantly recurrent, including the “extrasystolic form” of Gallavardin.
III. Atrial focal tachycardias:
1. Paroxysmal (mainly trigger).
2. Chronic, incessant, constantly recurring, caused by trigger activity or, more often, abnormal automatism.
IV. Atrial tachycardia with 2nd degree AV nodal block:
1. Paroxysmal (trigger, including digitalis-toxic form) Lown-Levine.
2. Chronic or constantly recurrent (extrasystolic) Gallavardin
V. Atrial multifocal tachycardia.
1. Paroxysmal (trigger, including pulmonary-hyxic form) Lipson and Naimi.
2. Paroxysmal (re-entry, pre-fibrillation and post-defibrillation).
VI. Atrial parasystolic tachycardia:
1. Classic type.
2. Modulated type.

The possibility of the occurrence of sinus node reciprocal or sinus AT was predicted back in 1943 by P.Barker, F.Wilson, F.Johnson, but only 27 years later O.Narula presented its electrophysiological characteristics. In our observations, the proportion of sinus AT among all atrial tachycardias was only 1.1%, although some other clinicians encountered it several times more often. We consider it useful to divide this form of tachycardia into a variant that occurs in patients with SSSS, when a long pause is recorded after the termination of the attack, and a variant without SSSS. In the first case, which occurs more frequently, one should not resort to beta-blockers or verapamil, but treatment with an atrial pacemaker is indicated. In the second case, a beta-blocker or verapamil is used without fear and often with success.

We observed a 36-year-old patient suffering from mild form diabetes mellitus, who suffered intermittent attacks sinus tachycardia. Tachycardic P waves did not differ in the patient from sinus P waves; P"-R intervals were longer Р-R intervals; Sinus extrasystoles were also recorded (Fig. 1).

Rice. 1. Sinus reciprocal paroxysmal tachycardia. Explanations in the text.

Other observations of sinus reciprocal AT were made in a 58-year-old man who suffered from arterial hypertension. His attacks of palpitations lasted up to 3-4 hours at a rhythm frequency of 160-180 per minute. The last attack of tachycardia occurred after intravenous injection 1 ml of atropine sulfate, which was prescribed to the patient for sinus pause. On the His bundle electrogram at the time of tachycardia, waves A were identical to sinus waves A. The attack of tachycardia was easily eliminated by three electrical stimuli with a frequency of about 200 per minute.

The next class of atrial tachycardias is represented by reciprocal tachycardias with localization of the re-entry circle within the atrial myocardium. The electrophysiological features of these ATs were indicated in 1971 by Goldreyer D.N. Darnato A.N. and independently of them - in 1975 Coumel Ph, Barold S.S.. According to our data, atrial reciprocal ATs account for 2-3% of atrial tachycardias. The re-entry zone can be located in any part of the right and left atria, including the Bachmann bundle in the left atrium. The possibility of longitudinal dissociation of this beam into two channels was shown in an experiment by Ogava S. (1977). IN last years the importance of the formation of the re-entry circle in the crista termianalis zone - in the right atrium is emphasized, which causes the formation of right atrial reciprocal tachycardia (Kushakovsky M.S., Grishkin Yu.N., 1993).

Patient A., 48 years old, suffered frequent attacks of atrial tachycardia, although the patient had no obvious organic changes. During an electrophysiological study, an atrial extrastimulus applied after a sinus impulse (with an interval of A1-A2 = 390 ms) caused an attack of tachycardia. The return cycle, i.e., the interval between the extrastimulus and the first tachycardic complex A2-A3 = 440 ms. When tachycardia is repeated, the coupling interval extrastimulus A1-A2 was shortened to 350 ms, while the return cycle increased to 490 ms. Consequently, in the tachycardia zone, inverse relationships between the intervals of extrastimuli and return cycles were revealed, which, according to H. Wellens, P. Burgada (1988), M .Rosen (1988) is typical for re-entry (reciprocal) tachycardias.Examples of reciprocal atrial AT are shown in Fig. 2.a, b.

Figure 2. a - atrial reciprocal paroxysmal tachycardia; b - atrial reciprocal unstable paroxysmal tachycardia.

Sometimes such tachycardias acquire a recurrent or constantly recurrent character, combined with single or paired atrial extrasystoles of the same shape and at the same intervals as in the first tachycardic complexes. These features correspond to the signs of extrasystolic tachycardia, which are described by L. Gallavardin (1927).

Focal atrial tachycardias constitute class III tachycardias. They account for 10.4% of all atrial tachycardias; in children they occur 2 times more often. These tachycardias are predominantly triggered (delayed post-depolarizations) or tachycardias formed on the basis of abnormal automatism. In 85% of cases, focal tachycardias acquire a constantly recurrent or almost continuous form.

Focal triggered atrial tachycardias are characterized by 3 important electrophysiological signs: 1) a direct relationship between the extrastimulus or last stimulus coupling intervals and return cycles, which distinguishes these tachycardias from re-entry tachycardias; 2) direct relationship between the frequency of electrical stimulation and the frequency of evoked tachycardia; 3) easier reproduction of tachycardias with frequent stimulation of the atria than with estrastimulation, in contrast to reciprocal ATs.

It should be emphasized that in the materials of Yu.N. Grishkina (1993) trigger mechanisms of focal tachycardias were predominant; their share amounted to 80% of the number of atrial tachycardias reproduced during EPI, the mechanisms of which were successfully reproduced.

In Fig. Figure 3 demonstrates triggered focal PT. The “cooling period” characteristic of these forms of tachycardia towards the end of the attack is clearly visible. Another example of triggered atrial tachycardia is shown in Fig. 4, a. This is left atrial tachycardia (P waves in lead V1 with a “shield and sword” shape); The figure did not include the “warm-up” period at the beginning of the attack, characteristic of this type of tachycardia. In Fig. Figure 4b shows the warm-up period of trigger tachycardia.

Rice. 3. Inferior atrial focal tachycardia. Explanations in the text.

Rice. 4. a - left atrial focal paroxysmal tachycardia (“a special form of the P wave” in lead V1, paired left atrial extrasystoles; b - focal triggered atrial tachycardia with AV block.

Focal automatic tachycardias, unlike trigger ones, usually begin in the late diastole phase sinus rhythm, without extrasystole (Fig. 5), they are not reproduced and are not eliminated by electrical stimulation or cardioversion of the atria.

Rice. 5. Focal automatic (abnormal automatism) atrial tachycardia.

In a young woman, the atrial rate was never below 100 per minute; with excitement, it increased to 200 per minute. In Fig. 6.a, lower atrial focal tachycardia is recorded with a frequency of about 150 per minute, in Fig. 6.b, the same tachycardia was registered, which acquired a constantly recurrent character.

Rice. 6. Focal automatic tachycardia of constant-return type. Explanations in the text.

Another example of focal automatic tachycardia is shown in Fig. 7. The differences between P"-P" and AV block 2;1, 3:1, 4:9 are visible. In Fig. Figure 8 shows focal atrial tachycardia (apparently of an automatic type), a transesophageal ECG was recorded.

Rice. 7. Focal automatic tachycardia with AV block.

Rice. 8. Focal automatic tachycardia; registration of transesophageal ECG.

Particular attention should be paid to the issue of long-term focal atrial tachycardias. According to our observations, this is, firstly, the so-called “children’s” or “fast” subtype of focal tachycardia. In persons suffering from such tachycardia, when mapping the atria, an arrhythmogenic focus is often found in the right or, more often, in the left atrium; Cardiac surgeons destroy these lesions using radiofrequency current or remove them. If it is possible to record action potentials in the removed tissue, then either abnormal automatic activity or delayed afterdepolarizations above the threshold amplitude are found in them.

We distinguish several electrocardiographic variants of stable, long-term atrial tachycardias. The first of them: chronic tachycardia in the form of extended continuous unfragmented tachycardic chains, persisting for weeks or months, but ending abruptly with the restoration of sinus rhythm. The second option: continuous tachycardia, when there are significant pauses in long chains, but sinus complexes never appear in them. The third option: recurrent or constantly recurrent tachycardia, when the tachycardic series are separated from one another by one or more sinus complexes.

Class IV in our classification consists of atrial tachycardias with 2nd degree AV nodal block. Generally speaking, any atrial tachycardia whose rate exceeds the Wenckebach point can be complicated by type I 2nd degree AV block. Here we will talk about a special form of atrial tachycardia associated with digitalis intoxication. Digitalis is responsible for both pathological phenomena: focal triggering activity in the atria and AV nodal block. This form of tachycardia was described by Lown B., Levine H. (1958). It can be combined with atrial extrasystole and acquire a constantly recurrent character, i.e. Galaverden type. In Fig. Figure 9 (see also Figure 7) shows 2 examples of this tachycardia with 2:1 AV block. Sometimes on the ECG the first tachycardic P wave is already blocked.

Rice. 9. Atrial tachycardia with AV block.

The last class of atrial tachycardias is represented by multifocal or multifocal tachycardias. They occur more often in patients with chronic bronchopulmonary diseases. This form of arrhythmia was first described by M. Lipson and S. Naimi (1970). According to modern concepts, the basis of such tachycardia is a trigger mechanism (Fig. 10).

Rice. 10. Multifocal atrial tachycardia (P waves of three to four types).

In conclusion, we note that an experienced, educated clinician can recognize the type of atrial tachycardia using an ECG in 75% of cases. It is hoped that this article, which draws electrocardiographic-electrophysiological parallels, will help improve the diagnosis of these tachycardias.

LITERATURE

1. Kushakovsky M.S. Cardiac arrhythmias. -1992,1999. -Folio. -639 pp.

2. Kushakovsky M.S., Zhuravleva N.B. Atlas of electrocardiograms. Arrhythmias and heart block. - 1999, - Folio, - 410 p.

3. Kushakovsky M.S., Grishkin Yu.N. Clinical and pathogenetic classification of atrial tachycardias and their features. // International medical reviews. -1993-N. 4, -s. 317-323.

4. Grishkin Yu.N. Tachycardia: electrophysiological mechanisms; reactions to antiarrhythmic drugs. -St. Petersburg.-GIDUV.-1993.-46p.

5. Revishvili A.Sh., Avaliani Yu.G., Ermolenko M.L. and others. Electrophysiological diagnostics and surgery supraventricular tachycardia // Cardiology, -1990, - N. 11, - p. 56-60.

6. Barkov P.S., Wilson F.N., Johnson F.D. The mechanism of auricular paroxysmal tachycardia // Amer. Heart J. - 1948.- V, 26.- P. 435-442.

7. Bouveret Z. De la tachycardie essentielle paroxystique // Rev. Med.- 1889.- V. 9.- P. 753-761.

8. Brugada P., Ferre J., Green M et al. Observations in patients with supraventricular tachycardia // Amer. Heart J.- 1984.- V. 107.- N. 3.- P. 556-570.

9. Coumel Ph, Barold S.S. Mechanisms of supraventricular tachycardia. In Narula O.S. (ed.) Yis Bandle Electrocardiography and Clinical Tlectrophysiology // Philadelphia.- F.A. Davis.- 1975.

10. Galaverdin Z. Extrasystolie ventriculare a paroxysmal tachycardia prolonges // Arch. Mal. Coeur.- 1922.- V. 15.- P. 774-782.

11. GoldreyerD.N. Darnato A.N. Essential role of atrioventricular conduction in the initiation of paroxysmal supraventricular tachycardia // Circulation.- 1971.- V. 43.- P. 679-687.

12. Narula O.S. Sinus node re-entry. A mechanism for supraventricular tachycardia // Circulation.- 1974.- V. 50.- P. 1114-1128.

13. Lown B., Levine H. Atrial arrhythmias, digitalis and potassium. - N.Y. - 1958. - 95p.

14. Lipson M.J., Naimi Sh. Multifocal atrial tachycardia // Circulation.- 1970.- V. 42.- P. 397-409.

15. Ogava S. et al. Longitudinal dissociation of Buchmans bundle as a mechanism of paroxysmal supraventricular tachycardia // Amer. J. Cardiol.- 1977.- V. 40.- P. 915-922.

16. Rosen M.R..The links between basic and clinical cardiac electrophysiology // Circulation.- 1988.- V. 77.- P. 251-263.

17. Wellens H.J.J., Brugada P., Bar F. Indications for the use of intracardiac electrophysiologic studies for the diagnosis of site of origin and mechanism of tachycardia // Circulation.- 1987.- V. 85.- P. 100-115.

@ 2024 wowway.ru - Diets and nutrition. Diagnostics and tests. Medicines. Cholesterol. Atherosclerosis