Hidden svv syndrome. Wolf-Parkinson-White syndrome: causes, symptoms, diagnosis, treatment. Characteristic features of the ECG in WPW syndrome

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Symptoms and course of the disease

Wolff-Parkinson-White syndrome can be asymptomatic if the heart rate does not exceed 200 beats per minute and is detected only by cardiac examination. If tachycardia exceeds 200 heartbeats, clinical manifestations occur in the form of a feeling of the heart “jumping out”, dizziness, and loss of consciousness often occurs.

According to statistics, in 70% of patients, VPU syndrome occurs in a mild form, without causing circulatory disorders and disability due to adaptive mechanisms.

The main manifestations of WPW syndrome:

1. Sudden onset of palpitations.
2. Interruptions in the functioning of the heart.
3. Throbbing in the head or throat.
4. General weakness, dizziness, decreased tolerance to physical activity, increased fatigue during an attack.
5. Possible loss of consciousness.
6. Dyspnea.
7. During an attack, dizziness or loss of consciousness may develop.
8. Decreased blood pressure (hypotension or unstable blood pressure).

Wolff-Parkinson-White syndrome can be accompanied by sudden episodes of very fast heartbeats and a palpitating sensation.

Already in children of the first year of life, with a prolonged attack, heart failure can develop. Sometimes the child seems to be suffocating; sometimes he sleeps all the time, stops eating well; rapid visible pulsations of the chest wall appear.

The first episodes usually occur in the teens or early 20s. Typical attacks begin suddenly, often during physical activity. They last from a few seconds to several hours, but rarely longer than 12 hours. In a young and otherwise physically healthy person, attacks of tachycardia usually cause few symptoms, but very fast heartbeats are unpleasant and distressing to the person. Sometimes they can lead to fainting or heart failure.

The tachycardia typical of Wolff-Parkinson-White syndrome sometimes develops into atrial fibrillation. The latter is especially dangerous for about 1% of patients with Wolff-Parkinson-White syndrome, because in them the additional conduction pathway can very quickly conduct many more impulses to the ventricles than the normal pathway. The result is an extremely fast ventricular rate, which is potentially life-threatening. Not only does the heart work very inefficiently when the ventricles contract at this rate, it can progress to life-threatening ventricular fibrillation.

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Treatment of the disease

There are two treatment methods for WPW syndrome: conservative and surgical.

1. Conservative method. Prevention of attacks of tachycardia (rapid heartbeat). For this purpose, prophylactic antiarrhythmic drugs are used (drugs that prevent the development of rhythm disturbances (any rhythm other than the normal one - the rhythm of a healthy person). Some antiarrhythmic drugs are contraindicated in WPW syndrome, as they can worsen its course. These are: slow calcium channel blockers (drugs , affecting the cells of the heart and blood vessels, causing a decrease in heart rate, reducing vascular tone); β-blockers (drugs that prevent the stimulation of receptors for adrenaline and norepinephrine (stress hormones)); cardiac glycosides (drugs that increase the force of heart contractions). Termination attack of tachycardia.For this, intravenous administration of antiarrhythmic drugs is used.
2. Surgical method. Indications for surgical treatment are:

• frequent attacks of atrial fibrillation (more than 1 time per week);
• attacks of tachycardia with impaired general circulation (loss of consciousness, weakness, decreased blood pressure);
• persistence of tachycardia attacks when taking antiarrhythmic drugs;
• situations where long-term drug therapy is undesirable (young age).

If conservative treatment is ineffective, as well as with tachycardia of more than 200 beats per minute, surgical treatment is used - an artificial pacemaker is implanted into the heart or destruction of the additional nerve bundle of Kent.

A popular treatment method for this disease is radiofrequency ablation of the Kent beam. The method has significant advantages over the implantation of a pacemaker, since it does not require opening the chest, implantation of equipment and its care, constant monitoring by a doctor and taking anticoagulants. The essence of the procedure is that a conductor (thin tube) is inserted into the heart through the femoral vessels. An impulse is sent through the conductor, destroying (cauterizing) the beam. After the manipulation, testing is carried out to monitor its effectiveness. If necessary, repeat ablation is performed immediately until the full effect is achieved.

Diagnosis of the disease

Any diagnosis begins with a visual examination by a specialist who, while listening to the work of the myocardium, observes pathogenic noises. In addition, abnormal heart rate also causes a certain amount of alarm, forcing a full clinical examination.

Diagnosis of Wolff-Parkinson-White syndrome is not limited to just a conventional electrocardiographic study. Modern methods are used:

• daily (Holter) and fragmentary ECG monitoring;
• electrophysiological study of the heart (EPS);
• endocardial mapping;
• computed tomography of the heart;
• ultrasound scanning;
• echocardiography;
• Magnetic resonance imaging;
• esophageal cardiography, which gives more accurate results compared to a conventional ECG;
• Holter cardiography, which allows you to constantly record the patient’s heart rhythm throughout the day in his usual mode of life, both during wakefulness and during sleep, using a special portable electronic sensor.

Typically, a full range of diagnostic measures takes no more than two days.

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Since the pathologies are very different, their treatment methods also differ significantly from each other. Vascular surgery in Israel carries out a variety of operations by type, level of complexity, etc. which effectively help eliminate the problem and save a person’s life.

Wolff-Parkinson-White syndrome (WPW) is a syndrome of abnormal excitation of the ventricles of the heart along the accessory duct between the ventricle and the atrium. Many people with WPW syndrome do not experience significant health problems until a certain point. And although WPW syndrome cannot always be detected on an ECG, approximately 0.15 to 0.30% of the total population of the planet suffers from this pathology. Men are more susceptible to this disease than women.

general information

WPW syndrome was first isolated and described by three doctors independently in 1930, but it was not named until ten years later.

Essentially, WPW syndrome is a heart rhythm disorder caused by the formation of an additional channel between the atrium and ventricle, bypassing the normal structure of the cardiac conduction system.

Cardiac impulses travel faster along the accessory connection, which leads to overexcitability of the ventricles. This sometimes appears on the ECG as a delta wave.

WPW syndrome is a heart rhythm disorder caused by the formation of an additional channel between the atrium and ventricle

Etiology

The disease is a congenital pathology of the structure of the heart, the cause of which is currently unknown. In some cases of the disease, a connection with the development of the syndrome and a mutation in the PRKAG2 gene, which is inherited in an autosomal dominant manner, has been identified.

Manifestations of the disease

The onset of WPW syndrome will vary depending on the age at which the disease appears. All age categories are susceptible to this pathology, however, most often the disease is detected in the patient’s childhood or adolescence (from 10 to 20 years).

The syndrome is not associated with structural abnormalities of the heart, but may be a concomitant pathology of congenital defects.

In clinical practice, it is customary to distinguish forms of the disease:

• latent – ​​absence of signs of ventricular overexcitation during sinus rhythm;
• manifesting - a combination of ventricular overexcitation and tachyarrhythmia;
• intermittent – ​​transient signs of ventricular excitation, sinus rhythm with confirmed AVRT;
• multiple – the presence of two or more additional channels;
• WPW phenomenon - the absence of rhythm disturbance in the presence of a delta wave on the ECG.

Depending on the age of the patient during the period of manifestation (manifestations of the disease after a latent course), symptoms may vary.

WPW phenomenon – absence of rhythm disturbance in the presence of a delta wave on the ECG

WPW syndrome in newborns has the following symptoms:

• tachypnea (rapid breathing);
• pallor;
• anxiety;
• refusal to feed;
• sometimes fever may occur.

SVC syndrome in older children usually has the following symptoms:

• feeling of heartbeat;
• chest pain;
• labored breathing.

Mature and elderly patients may describe the following:

• sudden stabbing pain in the heart;
• throbbing sensation in the head or throat;
• dyspnea;
• rapid pulse (usually the pulse is so fast that it is almost impossible to count);

Increased heart rate, usually the pulse is so fast that it is almost impossible to count

• weakness;
• unstable blood pressure levels;
• dizziness;
• decreased activity;
• rarely – loss of consciousness.

In this case, during inspections and examinations the following may be observed:

• In the vast majority of cases normal result cardiograms.
• During episodes of tachycardia, the patient experiences increased sweating, decreased blood pressure, and “coolness” of the skin.

Diagnostics

If a patient is suspected of having WPW syndrome, a comprehensive diagnosis is necessary, including a number of clinical, laboratory and instrumental examinations:

• daily ECG monitoring (electrocardiogram using the Holter method);
• electro-physiological study of the cavities of the heart;
• EchoCG;

Ultrasound of the heart, one of the types of diagnosis of the disease

• TEES (transesophageal cardiac conduction system test);
• extended blood test;
• liver tests;
• kidney function analysis;
• hormonal panel (in this case, the thyroid gland is examined);
• drug screening.

Treatment and prevention

Provided there is no deterioration, SVC syndrome does not require specific treatment. Therapy will be aimed at preventing attacks.

The main method of preventing recurrence of SVC syndrome is catheter ablation. This is a surgical operation to destroy the source of arrhythmia.

For pharmacological prevention of episodes of tachycardia, antiarrhythmic and antihypertensive drugs are used (if the patient does not have a decrease in blood pressure):

• "Amiodarone";
• "Cordaron";
• "Sotalol";

Cordarone tablets 200 mg No. 30

• "Rotaritmil";
• "Disopyramide".

However, one should be careful with antiarrhythmic drugs, which can improve impulse conduction and increase the refractory period of the AB junction. In this case, drugs from the following groups will be contraindicated:

• calcium channel blockers;
• cardiac glycosides;
• B-blockers.

If supraventricular tachycardia develops against the background of SVC, ATP (adenosine triphosphoric acid) is used.

If atrial fibrillation occurs, defibrillation is performed.

Forecasts

SVC syndrome with timely treatment and compliance with preventive measures has a favorable prognosis. The course of the disease, after its detection, depends on the duration and frequency of tachycardia attacks. Attacks of arrhythmia rarely lead to circulatory problems. In 4% of cases, death is possible due to sudden cardiac arrest.

Patients diagnosed with SVC syndrome are advised to undergo systematic examinations and consultations with a cardiologist. Patients need to undergo an ECG examination at least once a year.

Even if the disease occurs in a latent or mild form, there is a risk of negative dynamics in the future.

Excessive physical and emotional stress is contraindicated for patients. If you have WPW syndrome, you should be careful with any type of physical activity, including therapeutic exercise. physical culture and sports. The decision to start classes should not be made independently; in such a situation, consultation with a specialist is required.

The heart of a healthy person works at a rhythm of about seventy beats per minute; this is an independent process, unlike the movements of the arms and legs, so the person does not pay attention to it. But sometimes disturbances arise associated with the acceleration or deceleration of its pace. Seizures were first described in the thirtieth year of the twentieth century by scientists Wolf, Parkinson and White. The cause of the pathology was identified - the emergence of another excitation pathway in the heart muscle. It was named Wolff-Parkinson-White syndrome (WPW).

In the normal state, the conduction system of the heart muscle is presented in such a way that the transmission of electrical excitation occurs smoothly from the upper part to the lower part along a given path:

• The formation of the heart rhythm occurs in the cells of the sinoatrial node in the right atrium;
• After this, it passes into the left atrium and reaches the atrioventricular node;
• Next, the excitation through the bundle of His along its two legs spreads to the lower part of the heart;
• With the help of Purkinje fibers, all cells of both lower chambers are saturated with excitation.
• When passing this path, the work of the heart muscle is synchronized and coordinated.

When pathology occurs, electrical excitation bypasses the atrioventricular node and enters the right or left ventricles. Wolf Parkinson-White syndrome occurs when another bundle appears that is capable of transmitting impulses directly from the upper chambers of the heart to the lower ones. Because of this, a rhythm disturbance occurs. The ventricles begin to excite faster than necessary, which is why a rapid heartbeat occurs.

This phenomenon can also occur in healthy people, in the absence of heart complaints. During preventive examinations, this syndrome was identified in forty percent of people, and upon repeated examinations it disappeared by itself. This has left scientists confused. Therefore, another definition was introduced - the ERW phenomenon.

This disease could manifest itself under severe emotional and physical stress, or with excessive consumption of alcoholic beverages. According to statistics, three hundredths of a percent of deaths were caused by the Wolff-Parkinson-White phenomenon. Scientists have not yet established the exact causes of WPW syndrome.

Symptoms

Like many diseases, SVC syndrome has its own symptoms:

• Palpitations;
• Loss of balance in space;
• Fainting;
• Not enough air.

In children

Signs of PVP syndrome in young children are refusal to feed, excessive sweating, crying, weakness, and the frequency of contractions increases to three hundred beats per minute.

There are three ways of progression of the disease:

• There are no symptoms (about forty percent of patients);
• Self-limiting attacks that last for twenty minutes;
• In the third stage, palpitations do not go away on their own. With the use of special medications, the attack disappears after three hours.
• At the next stage, the attack lasts more than three hours, and is characterized by very strong dissociation in the rhythms of the heart parts. Medicines don't help. In such cases, surgery is performed.

During the examination, the cardiac region is listened to and analyzed. For a more accurate diagnosis, an electrocardiogram is used.

When examining Wolff–Parkinson–White syndrome, the patient's ECG reveals the following signs:

• Shortening the period of transition of an electrical impulse from the atrium to the ventricle.
• On the electrocardiogram (), experts note a wave. Its formation suggests that there is a disturbance in the excitation of the ventricles. Its value on the cardiogram indicates the speed at which the impulse travels from the upper parts of the heart to the lower ones. The smaller it is, the more correct the connection.
• Expansion of the ventricular complex, recorded during ventricular pulsation.
• Decrease in heart rate period.
• The presence of a negative T-wave.

A transitional syndrome is distinguished separately. This suggests that the device, when the pattern of cardiac impulses is disturbed, also shows normal segments.

Danger

The main danger of SVC syndrome is its suddenness. Even when there are no special signs, for example, during the first or second stage of the disease, you should not forget about it. After all, WPW syndrome can remind itself at the most inopportune moment, for example, when playing football with friends in the yard.

As mentioned above, severe emotional and physical stress can lead to dire consequences, including death. Therefore, if the doctor has discovered a pathology, you should not ignore it even in the absence of symptoms.

Treatment

Wolff-Parkinson-White syndrome has existed for quite a long time, so people have come up with quite a few ways to treat it. These include medication, surgery, electrophysiology, and vagus nerve activation.

Treatment with drugs. For Wolff–Parkinson–White syndrome, the following groups are used:

• affect the receptors of the heart, due to which the rhythm slows down. Not recommended for low blood pressure. Effective in sixty percent of cases.
• Procainamide is applicable only in clinics or at home by a doctor. Twenty milliliters are administered over ten minutes, while monitoring blood pressure and rhythm. The patient must lie down, as the drug sharply reduces blood pressure. In eighty cases out of a hundred, the heart rhythm is restored.
• Propafenone has many contraindications associated with. When used in ninety percent of cases, it restores heartbeat. In addition, it is very convenient because it is presented in the form of a tablet, which is very convenient.
• Such groups of medications as calcium channel blockers and adenosine triphosphates are strictly contraindicated, as they cause asynchrony in the activity of cardiac muscle fibers.

Treatment with surgery. This method of treating Wolff–Parkinson–White syndrome is applicable in extreme cases at the last stage. It is very effective; in more than ninety percent of cases, patients were no longer bothered by problems with rapid heartbeat.
It involves removing the pathologically formed bundle. Thus, the transmission of nerve impulses is restored.

There are indications for surgery:

• If a person has attacks frequently;
• The attacks last more than three hours and cannot be treated with drugs;
• The syndrome is transmitted genetically.
• The operation is also carried out for those people whose profession is to save other people.

Electrophysiological methods. Electrode intervention is carried out in two ways:

• . Here the electrode is inserted through the esophagus so that it is closest to the heart muscle. A small current discharge is supplied through it, which restores rhythm. If the operation is successfully performed, the effectiveness of the method is ninety-five percent. But there are cases when the current led to erratic contraction of the heart tissue, so specialists always have a defibrillator with them before such an intervention.
• Defibrillation. The method is applicable in severe cases, when various contractions of the muscle fibers of the heart can lead to death. Suppresses any pathological processes, after which the normal rhythm returns.
• Activation of vagal reflexes. It is known that impulses that stimulate the heart work along sympathetic nerve fibers, and inhibitory ones through parasympathetic fibers. It follows that to eliminate palpitations, you need to launch the second ones.

There are two methods for this:

• Pressing on the eyes for half a minute reduces the frequency of the rhythms.
• Holding your breath and contracting your abs activates the vagus nerve.

Thus, PVP syndrome in children and adults is a serious disease that cannot be ignored even in the early stages. The main reason for the accelerated rhythm of the heart muscle with it is the formation of an additional bundle, which is capable of transmitting nerve impulses directly from the atrium to the ventricle.

The disease occurs in both men (seventy percent), women, and even children. Depending on the stage of the syndrome, symptoms vary. At the beginning there are no signs, and therefore the person does not know that he is sick.

In order to accurately determine Wolff–Parkinson–White syndrome, you need to be examined by a cardiologist. Treatments include medications, electrophysiological techniques, surgery, or activation of reflexes through special exercises.

Wolff-Parkinson-White syndrome (WPW syndrome) is an electrocardiographic syndrome that is associated with ventricular preexcitation resulting from the presence of an additional (abnormal) atrioventricular junction (AVJ). Pre-excitation of the ventricles provokes the development of various arrhythmias, so the patient may experience supraventricular tachycardia, atrial fibrillation or flutter, atrial and ventricular extrasystole and corresponding subjective symptoms - palpitations, shortness of breath, hypotension, dizziness, fainting, pain in chest.

ICD-10	I45.6
ICD-9	426.7
DiseasesDB	14186
MedlinePlus	000151
eMedicine	emerg/644 med/2417
MeSH	C14.280.067.780.977
OMIM	194200

General information

The first known description of an anomalous atrioventricular (conducting) pathway belongs to Giovanni Paladino, who in 1876 described muscle fibers located on the surface of the atrioventricular valves. Giovanni Paladino did not connect the identified structures with the conductivity of the heart, but assumed that they contribute to the contraction of the valves.

The first ECG reflecting ventricular preexcitation was presented in 1913 by A.E. Coch and F.R. Fraser, however, they did not identify a cause-and-effect relationship between the detected preexcitation and tachycardia.

Similar electrocardiographic features in patients suffering from paroxysmal tachycardia were recorded by F.N. in 1915. Wilson, and in 1921 - A.M. Wedd.

G.R. Mines in 1914 put forward the hypothesis that the accessory path may be part of a re-entry circuit (re-entry of an excitation wave).

On April 2, 1928, Paul White was approached by a 35-year-old teacher suffering from attacks of palpitations. During the examination, Louis Wolff (assistant Paul White) conducted an electrocardiographic study, which revealed a change in the QRS complex and shortening P-Q interval.

Abnormal ventricular depolarization, causing changes in the initial part of the QRS complex, for a long time was the subject of debate, since the detailed mechanism of tachycardia development remained unclear before the advent of intracardiac signal recording techniques.

By 1930, L. Wolff, P. White and the Englishman John Parkinson summarized 11 similar cases, defining a combination of shortening of the P-Q interval, atypical blockade of the leg and paroxysms of tachycardia, as well as atrial fibrillation and flutter, as a clinical electrocardiographic syndrome.

1. Scherf and M. Holzman in 1932 suggested that ECG changes are provoked by an abnormal atrioventricular connection. F.S. came to the same conclusions, regardless of the researchers’ data, in 1933. Wood and S.S. Wolferth. The prerequisite for these conclusions was the discovery in 1893 by Kent of an additional atrioventricular muscle bundle in animals (“Kent’s bundle”).

In 1941 S.A. Levin and R.B. Beenson proposed to use the term “Wolff-Parkinson-White syndrome” to refer to this syndrome, which is still used today.

At the end of the 60s of the twentieth century, during open heart surgery, thanks to the epicardial mapping technique of D. Durrer and J.R. Ross recorded ventricular preexcitation. Using programmed stimulation, D. Durrer and co-authors proved that as a result of premature atrial and ventricular contraction in patients with WPW syndrome, tachycardia can occur and stop.

In 1958, R.C. Truex et al., in a study of the hearts of fetuses, newborns, and infants during the first 6 months of life, identified numerous additional connections in the openings and crevices of the annulus fibrosus. These data were confirmed in 2008 by N.D. Hahurij et al., who discovered the presence of additional muscle tracts in all examined embryos and fetuses at early stages of development.

In 1967 F.R. Cobb and colleagues demonstrated the possibility of treating WPW syndrome by eliminating abnormal conduction during open-heart surgery.

The introduction of high-frequency destruction techniques allowed M. Borggrefe to eliminate the right-sided additional ABC in 1987, and in 1989 K.N. Kuck performed successful destruction of the left-sided anomalous connection.

Wolff-Parkinson-White syndrome is detected in 0.15 - 0.25% of people from the general population. The annual increase is 4 new cases per year per 100,000 population.

The prevalence of the syndrome increases to 0.55% in individuals who are closely related to patients with WPW syndrome. With the “familial” nature of the disease, the likelihood of having multiple additional ABCs increases.

Arrhythmias associated with additional AVS account for 54–75% of all supraventricular tachycardias. In manifesting WPW syndrome, the share of paroxysmal atrioventricular reentrant tachycardia (PAVRT) accounts for 39.4%, and the share of latent retrograde DAVS accounts for 21.4%.

About 80% of patients with WPW syndrome are patients with reciprocal (circular) tachycardia, 15-30% have atrial fibrillation, and 5% have atrial flutter. Ventricular tachycardia is detected in rare cases.

Although accessory AV junctions (AVJs) are a congenital abnormality, WPW syndrome may first present at any age. In most cases, the clinical manifestation of the syndrome is observed in patients aged 10 to 20 years.

This syndrome in children is detected in 23% of cases, and according to some authors, it most often manifests itself in the first year of life (20 cases per 100,000 are registered among boys, and 6 per 100,000 among girls), and according to other data most of cases are registered at the age of 15-16 years.

The second peak of manifestation of the syndrome occurs in the 3rd decade in men and in the 4th decade in women (the ratio of men to women is 3:2).

Mortality in WPW (sudden coronary death) syndrome is associated with the degeneration of atrial fibrillation into ventricular fibrillation and rapid ventricular response along one or more accessory pathways with a short anterograde refractory period. As the first manifestation of the syndrome, it is observed in a small number of patients. Overall, the risk of sudden coronary death is 1 in 1000.

Forms

Since abnormal conduction pathways are designated by the place of origin and the region of entry, in 1999 F.G. Cosio proposed an anatomical and physiological classification of the localization of DAVC (additional atrioventricular connections), according to which all DAVCs are divided into:

• right-sided;
• left-sided (observed most often);
• paraseptal.

In 1979, W. Sealy and co-authors proposed an anatomical and surgical classification, according to which the DPVS is divided into left-sided, right-sided, parietal, and also divided by the area of ​​the membranous septum adjacent to the fibrous ring, anteroseptal and posteroseptal.

There is also a classification by M. E. Josephson and co-authors, proposing to divide DPHS into:

• DPJS of the right free wall;
• DPJS of the left free wall;
• DPJS of the free posterior left wall;
• anterior septal;
• posteroseptal.

Depending on the morphological substrate of the syndrome, its anatomical variants with accessory muscle AV fibers and additional “bundles of Kent” (specialized muscle AV fibers) are distinguished.

Accessory muscle AV fibers can:

• pass through the accessory left or right parietal AV junction;
• pass through the fibrous aortic-mitral junction;
• come from the appendage of the left or right atrium;
• be associated with an aneurysm of the middle cardiac vein or sinus of Valsalva;
• be septal, superior or inferior paraseptal.

Specialized muscle AV fibers can:

• come from rudimentary tissue similar in structure to the atrioventricular node;
• enter the right bundle branch (be atriofascicular);
• enter the myocardium of the right ventricle.

• the WPW phenomenon, which is characterized by electrocardiographic signs of ventricular preexcitation as a result of impulse conduction through additional connections, but clinical manifestations of AV reciprocal tachycardia (re-entry) are not observed;
• WPW syndrome, in which ventricular preexcitation is combined with symptomatic tachycardia.

Depending on the distribution routes, there are:

• manifesting WPW syndrome, in which the depolarization front propagates along the DAVS in the anterograde direction against the background of sinus rhythm;
• a latent form of the syndrome, in which, against the background of sinus rhythm, there are no signs of ventricular preexcitation, conduction along the DAVS is retrograde, and through the normal AV connection is anterograde;
• latent form of the syndrome, in which signs of ventricular overexcitation are observed only with programmed or increasing stimulation, which is absent in the normal state;
• Intermittent WPW syndrome, in which intermittently manifested ventricular overexcitation alternates with normal AV conduction;
• multiple form of WPW syndrome, in which more than one additional atrioventricular connection is detected.

Reasons for development

Wolff-Parkinson-White syndrome develops as a result of preservation of accessory AV connections due to incomplete cardiogenesis. According to research, additional muscle tracts are normal in the early stages of fetal development. At the stage of formation of the tricuspid and mitral valves and fibrous rings, a gradual regression of additional muscle connections occurs. Accessory AV connections normally become thinner, their number decreases, and they are not detected already at the 21st week of gestation.

When the formation of fibrous AV rings is impaired, some of the additional muscle fibers are preserved and become the anatomical basis of the DAVS. In most cases, the histologically identified accessory pathways are “thin filaments” that bypass the structures of the normal conduction system of the heart, connecting the ventricles and atrial myocardium through the atrioventricular groove. Additional pathways are introduced into the tissue of the atria and the basal part of the ventricular myocardium at different depths (localization can be either subepicardial or subendocardial).

In the presence of WPW syndrome, concomitant congenital heart pathologies may be detected, although the syndrome is not structurally related to them. Such anomalies may be Elars-Danlos syndrome, Marfan syndrome, etc. In rare cases, congenital defects (Ebstein's anomaly, gastric and atrial septal defect) are also observed.

The presence of additional pathways may be familial in nature (usually a multiple form).

Pathogenesis

Wolff-Parkinson-White syndrome develops on the basis of pre-excitation with the participation of additional conducting structures capable of antegrade, retrograde conduction, or a combination of both.

Normally, conduction from the atria to the ventricles occurs via the AV node and the His–Purkinje system. The presence of additional pathways shunts the normal conduction path, so excitation of part of the ventricular myocardium occurs earlier than during normal conduction of the impulse.

Depending on the size of the part of the myocardium activated through the abnormal connection, the degree of preexcitation increases. The degree of preexcitation also increases with increasing frequency of stimulation, administration of adenosine, calcium and beta blockers, and atrial extrasystole due to prolongation of conduction time in the AVS. A syndrome in which left-sided lateral DAVS is detected is characterized by minimal preexcitation, especially in combination with accelerated conduction in the AV node.

Additional pathways with exclusively anterograde conduction are rarely detected, but those with only retrograde (latent form) are often detected. “Manifesting” DPVS usually conduct impulses in both anterograde and retrograde directions.

Paroxysms of supraventricular tachycardia, atrial fibrillation and flutter are caused by the formation of a circular wave of excitation (re-entry).

Induction of reentry tachycardia occurs if:

• two channels of conduction;
• via one of the channels of the unidirectional conduction block;
• the possibility of anterograde conduction, bypassing the block, through another channel;
• the possibility of retrograde conduction through one of the available channels.

Atrioventricular tachycardia associated with the re-entry mechanism in WPW syndrome is divided into:

• Orthodromic, in which impulses are anterogradely conducted through the atrioventricular (AV) node into the ventricles from the atrium using a specialized conduction system, and from the ventricles to the atria the impulse is transmitted retrogradely through the DPV. Depolarization of the ventricular myocardium is carried out by normal system Gisa–Purkinje. The ECG records tachycardia with “narrow” QRS complexes.
• Antidromic, in which impulses from the atria to the ventricles are transmitted using anterograde conduction through the DPJ, and retrograde conduction is carried out through the second DPJ (with plural form) or AV node. Excitation of the ventricular myocardium is observed in the area where the DAVS enters the ventricle (usually parietal, at the ventricular wall). The ECG records tachycardia with wide QRS complexes. This type tachycardia is detected in 5-10% of patients.

The location of the DAVS can be any area along the atrioventicular groove, except for the area between the mitral and aortic valves.

In most cases, left-sided abnormal connections are located under the epicardium, and the annulus fibrosus is developed normally. Right-sided abnormal connections are localized both endocardially and epicardially with equal frequency, and in most cases are accompanied by defects in the structure of the annulus fibrosus.

Often, additional ABCs are found to cross the atrioventricular groove diagonally, as a result of which the ventricular and atrial parts do not correspond to each other. The direction of the anomalous connections is characterized by a “centrifugal” character.

Symptoms

Before the clinical manifestation of WPW syndrome, which is possible at any age, the course of the disease may be asymptomatic.

Wolff-Parkinson-White syndrome is manifested by such heart rhythm disturbances as:

• reciprocal supraventricular tachycardia, which is detected in 80% of patients;
• atrial fibrillation (in 15-30%);
• atrial flutter in 5% of patients (frequency is 280-320 beats per minute).

In some cases, WPW syndrome is accompanied by atrial and ventricular extrasystole or ventricular tachycardia.

Arrhythmia occurs during physical stress, under the influence of emotional factors, or for no apparent reason. The attack is accompanied by:

• feeling of palpitations and heart sinking;
• cardialgia (pain in the heart area);
• feeling of lack of air.

With atrial fibrillation and flutter, dizziness, fainting, arterial hypotension, and shortness of breath occur.

Paroxysms of arrhythmia begin suddenly, last from a few seconds to several hours and can stop on their own. Attacks can be either daily or occur 1-2 times a year.

Structural pathologies of the heart are absent in most cases.

Diagnostics

To diagnose WPW syndrome, a comprehensive clinical and instrumental diagnosis is carried out:

• 12-lead ECG, revealing a shortened PQ interval (less than 0.12 s), the presence of a delta wave caused by “drain” contraction of the ventricles, and widening of the QRS complex more than 0.1 s. Rapid conduction of a delta wave through the AB junction causes it to expand.
• Transthoracic echocardiography, which allows visualizing cardiovascular anatomical structures, assessing the functional state of the myocardium, etc.
• Holter ECG monitoring to help detect transient arrhythmias.
• Transesophageal cardiac pacing, which helps to detect additional conduction pathways and provoke arrhythmia paroxysms, allowing us to determine the form of the disease. The manifesting syndrome is accompanied by signs of preexcitation on the initial electrocardiogram, which intensify with stimulation. With orthodomic reciprocal tachycardia, signs of preexcitation during stimulation suddenly disappear, and the St2-R2 interval increases.
• An electrophysiological study of the heart, which allows one to accurately determine the location of additional pathways and their number, as well as determine the clinical form of the syndrome.

WPW syndrome on the ECG in its latent form is reflected by the absence of signs of premature excitation of the ventricles during sinus rhythm. Electrical stimulation of the ventricles, which causes tachycardia in the patient, helps to identify the syndrome.

Differential diagnosis of WPW syndrome is carried out using bundle branch block, which is accompanied by a decrease in the frequency of tachycardia on the side of the accessory pathways.

Treatment

Wolff-Parkinson-White syndrome is treated with medication or surgery (the choice of method depends on the patient's condition).

Drug therapy includes constant use of antiarrhythmic drugs. For orthodromic tachycardia, drugs are used that affect:

• on the AV node and on the DAVS simultaneously (flecainide, propafenone, sotalol);
• on the AV node (digoxin), but only in cases of retrograde functioning DAVS;
• on DAVS (disopyramide, amiodarone, quinidine).

Since digitalis drugs, verapamil, diltiazem, adenosine (calcium blockers) for atrial fibrillation can increase the frequency of the ventricular response and thus provoke the development of ventricular fibrillation, these drugs are not prescribed.

Due to possible complications and the effectiveness of simpler methods, open heart surgery is performed exclusively in cases of concomitant pathology or the impossibility of catheter operations. Elimination of abnormal conduction is performed using endocardial or epicardial surgical access.

Antitachycardia devices are not currently used in WPW syndrome due to the risk of developing atrial fibrillation.

Most effective method treatment (successful for 95% of patients) is catheter radiofrequency destruction (ablation) of the DAVS, which is based on the destruction of pathological pathways. This method involves transaortic (retrograde) or transseptal access.

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© O.L. BOKERIA, A.A. AKHOBEKOV, 2015 © ANNALS OF ARRHYTHMOLOGY, 2015

UDC 616.12-008.311

DOI: 10.15275/annaritmol.2015.1.4

WOLFF-PARKINSON-WHITE SYNDROME

Article type: lecture by O.L. Bockeria, A.A. Akhobekov

FSBI " Science Center Cardiovascular Surgery named after. A.N. Bakulev" (director -

Academician of the Russian Academy of Sciences and Russian Academy of Medical Sciences L.A. Boqueria); Rublevskoe highway, 135, Moscow, 121552, Russian Federation

Bockeria Olga Leonidovna, Doctor of Medicine. Sciences, Professor, Ch. scientific associate, deputy head of the department; Akhobekov Albert Amalievich, Jr. scientific coll.; e-mail: [email protected]

Wolff-Parkinson-White syndrome (WPS) is the second most common cause of supraventricular tachycardia in the world. The morphological substrate of Wolff-Parkinson-White syndrome is represented by a muscular bridge that exists in addition to the specialized area of ​​the atrioventricular junction and is capable of conducting electrical impulses from the atria to the ventricles. Today, intracardiac electrophysiological study (EPS) is the “gold standard” for diagnosing Wolff-Parkinson-White syndrome and a mandatory stage of preoperative examination. Intracardiac EPI allows you to assess the risk of sudden death of a patient. Radiofrequency ablation, which is a safe and highly effective method of therapy, is currently considered the “gold standard” for the treatment of Wolff-Parkinson-White syndrome.

Key words: VPU syndrome; sudden cardiac death, treatment; radiofrequency ablation.

WOLFF-PARKINSON-WHITE SYNDROME O.L. Bockeria, A.A. Akhobekov

A.N. Bakoulev Scientific Center for Cardiovascular Surgery; Rublevskoe shosse, 135, Moscow, 121552, Russian Federation

Bockeria Ol"ga Leonidovna, MD, PhD, DSc, Professor, Chief Research Associate, Deputy Chief of Department; Akhobekov Al"bert Amalievich, MD, Junior Research Associate; e-mail: [email protected]

Wolff-Parkinson-White syndrome is the second most common cause of supraventricular tachycardia in the world. Morphological substrate of Wolff-Parkinson-White syndrome is presented by a muscle bridge, which exists in addition to the existing specialized area of ​​AV-connection and is able to conduct electrical impulses from the atria to the ventricles. Today intracardiac electrophysiological study is the "gold standard" for diagnosis of Wolff-Parkinson-White syndrome and an obligatory stage of preoperative examination. Intracardiac electrophysiologic study allows to evaluate the risk of sudden death of a patient. "Gold standard" treatment of Wolff-Parkinson-White syndrome is currently considered to be radiofrequency ablation, which is a safe and highly effective method of therapy.

Key words: WPW syndrome; sudden cardiac death, treatment; radiofrequency ablation.

the drome of ventricular pre-excitation fluctuates;

In 1930, L. Wolff, J. Parkinson and P. White described from 0.1% to 0.3% per 1000 population, and

whether ECG functional block syndrome is present in patients with congenital heart defects;

The length of the His bundle branch and the short interval is slightly higher and amounts to 0.5%. This"

P-R, which is observed in young people, physical syndrome is the second most common

Ski healthy people suffering from attacks caused by supraventricular tachycardia in the myocardium

tachycardia. re. Additional atrioventricular^

compounds (DPZhS) are present at birth, but subsequently they undergo self-destruction (apoptosis). It has now been revealed that in a number of cases, Wolff-Parkinson-White syndrome (WPU) is associated with a mutation in the PRKAG2 gene. However, the possibility of its hereditary transmission has not been proven.

DPVS are detected in more than 60% of children visiting hospitals with complaints of paroxysms of rapid heartbeat. The first episode of arrhythmia may be detected in utero, occur shortly after birth, or appear during puberty. It is extremely rare that the onset of the disease is possible at the age of 50 years or more. However, our own experience indicates that in the older category of patients, attacks occurred in their youth, but, according to the description of the patients themselves, they did not bother them, so they did not seek help from specialists.

Large studies have revealed that the closest relatives (mother, father, brothers, sisters) of a patient with VPU syndrome have DPHD in 3.4% of cases. However, this did not take into account latent forms of DPHS, which would have given a higher frequency of occurrence.

VPU syndrome is undoubtedly underdiagnosed, since the severity of preexitation along the DPVS can vary for various reasons (from the location of the beam and the amount of electricity conducted through it to factors such as antiarrhythmic therapy, age, etc.). What percentage of patients with the VPU phenomenon are asymptomatic is also unknown.

The morphological substrate of the VPU syndrome is the DPVS, or the so-called muscle bridges. DPVS are pathways between the myocardium of the ventricles and atria, existing in addition to the specialized region of the atrioventricular (AV) junction. Unless these pathways originate from areas of specialized tissue of the atrioventricular ring, first described by S. Kent, it is incorrect to designate them as “bundles of Kent”. In 1914, this scientist studied and described an additional node (connection), which was located in the right free wall of the atrioventricular ring and was represented by the structural elements of the compact part of the normal AV connection. There are reports in which histologically

The material shows the presence of DPVCs, consisting of elements of the conduction system of the heart, including nodular tissue.

DPVS was first identified histologically by F. Wood et al. , but its most accurate description is given by R. Ohnell. Most histologically identified accessory tracts represent thin filaments of working atrial myocardium. The width of these beams ranges from 0.1 to 7 mm (average 1.3 mm).

The bundles of Kent are called accessory connections because they begin and end in the working myocardium, in contrast to accessory tracts that are embedded in the specialized conduction system of the heart.

Additional pathways cannot be visually differentiated from the working myocardium, and therefore only accurate topical diagnosis of the area of ​​the earliest activation of ventricular depolarization through one of the types of cardiac mapping allows them to be identified for the purpose of further elimination. Currently, there are surface mapping systems that make it possible to determine the location of the DPJ non-invasively with an accuracy of 2-3 mm. DPVS can be localized along the AV groove along the perimeter of the right and left AV rings, in the area of ​​the septum, as well as in the area of ​​the mitral-aortic contact, where there is no contact of the left ventricular myocardium with the fibrous ring.

Classification of additional pathways

For clinical practice, the classification of ventricular preexcitation, proposed by R. Anderson and A. Becker in 1975 and approved by the European Ventricular Preexcitation Study Group, deserves attention. This classification is presented in Table 1.

Depending on the location, according to the ECG signs of M.E. Josephson subdivides DPHS into five types: 1) anterior septal; 2) posterior septal; 3) right-sided (along the right free wall of the right atrium); 4) posterior left-sided and 5) lateral left-sided - considering that there are ECG differences between the latter.

In 1978, J. Gallagher et al. According to epicardial mapping data, the following localizations of the RPVS were identified: 1) right anterior

Table 1

Anatomical classification of accessory pathways (R. Anderson, A. Becker)

New terminology for additional pathways

Former name

Atrioventricular AV connections

Nodoventricular connection between the distal part of the AV node and the interventricular septum

Fasciculoventricular connection between the common trunk of the His bundle or its left bundle and the ventricular myocardium (rarely functions)

Atriofascicular tract connecting the right atrium with the common trunk of the His bundle (rare)

Atrionodal tract between the SP node and the inferior part of the AV node

Hidden retrograde ventriculoatrial connections Multiple accessory tracts

Kent Bundles Maheim Fibers

Maheim fibers

Brechenmacher Tract

James Tract Retrograde Bundles of Kent

Multiple additional routes

Note. AB - atrioventricular; SP - sinoatrial.

paraseptal; 2) right front; 3) right lateral; 4) right rear; 5) right paraseptal; 6) left posterior paraseptal; 7) left rear; 8) left side; 9) left front; 10) left anterior paraseptal.

In 1998 M.S. Arruda et al. , having modified the classification of J. Gallagher et al., they proposed to subdivide DPHS according to their localization in three main areas:

1) septal DPVS: anteroseptal and anterior paraseptal along the tricuspid valve (TC) ring, midseptal along the TC ring, posteroseptal along the TC ring, posteroseptal along the mitral valve ring;

2) DPJS of the right free wall: right anterior, right anterolateral, right lateral, right posterolateral, right posterior;

3) DPJS of the left free wall: left anterolateral; left lateral, left posterolateral, left posterior.

In 1999 F.G. Cosio et al. proposed their anatomical and physiological classification of the localization of DPVS in VPU syndrome, taking into account the anatomical location in the chest and the structure of the heart, which, according to these scientists, is more correct. They divided the DPHS into three groups: right-sided, left-sided and paraseptal.

DPVC can also be classified according to the type of conduction: decremental (increasing slowdown of conduction along an additional pathway in response to an increase in the frequency of stimulation;

tions) or non-decremental - and also depending on whether they are capable of antegrade, retrograde conduction, or a combination thereof.

Clinical forms of Wolff-Parkinson-White syndrome

There are concepts of “phenomenon” and “syndrome” of premature excitation of the ventricles: the first includes those cases where there are only typical ECG changes, and the second - where there are also attacks of tachycardia. Clinically, the following forms of VPU syndrome are distinguished:

1) the manifesting form, which is characterized by the constant presence of a delta wave, present in 0.15-0.20% of the total population, antegrade and retrograde conduction along the DPV; the degree of preexcitation is determined by the ratio of conduction to the ventricles through the AV node and the His-Purkinje system;

2) intermittent form - detected mainly by clinical data; it is characterized by transient signs of pre-excitation (Fig. 1);

3) latent form - manifests itself with signs of preexcitation only when the atria are stimulated (most often the left, through the coronary sinus with invasive EPI) or when conduction through the AV node is slowed down as a result of massage of the carotid sinus, administration of verapamil or propranolol;

4) latent form, in which only retrograde preexcitation of the atrial

Rice. 1. Electrocardiogram of a 14-year-old boy with intermittent VPU syndrome (leads I, II, III, aVR, aVL, aVF, V1-V6 of standard ECG)

Rice. 2. Electrocardiogram of a 12-year-old girl with continuously recurrent orthodromic AV reentry tachycardia. Negative _P-waves are visible in leads II, III, aVF. P-R interval is shorter than R-P interval

diy, therefore paroxysms of antidromic tachycardia or atrial fibrillation with conduction through the RPV do not develop; with sinus rhythm, there are no signs of VPU syndrome (characteristic delta wave) on the electrocardiogram.

Hidden retrograde RPV can be of two types: fast (common) and slow (rare). Fast DPHS

are the basis of paroxysmal orthodromic AV reentry tachycardias, in which the V-A interval (R-P/) is less than 1/2 R-R; and the so-called slow DPVS are the basis of non-paroxysmal (persistent, chronic), or continuously recurrent orthodromic AV reentry tachycardias, in which the V-A interval (R-P/) is greater than 1/2 R-R (Fig. 2).

Rice. 3. Patterns of conduction through the accessory pathway (AP) and normal conduction system (AVN-HB) during orthodromic (left) and antidromic (right) tachycardia

The mechanism of tachycardia in VPU syndrome

D. Durrer et al. in 1967, for the first time, they were able to cause an attack of paroxysmal AV reentry tachycardia in a patient who had signs of VPU syndrome on the ECG. Depending on the size of the reentry loop, reciprocal arrhythmias are divided into macro- and microreentry. With macro-re-entry, the impulse circulates along an anatomically defined path - re-entry around the “anatomical obstacle”. With microreentry, the circulation of the impulse occurs along functional paths - re-entry according to the “leading circle” type. The latter is the path of shortest duration in which the impulse continues to circulate, exciting tissues that are in a relative refractory period; As a rule, a minimal number of cardiomyocytes and elements of the cardiac conduction system participate in this microcircle.

It is now generally accepted that paroxysmal tachycardia in VPU syndrome is a classic example of macroreentry due to the fact that the reentrant loop is large and includes the following structures: AV node, common trunk of the His bundle, bundle branch, network of fibers Purkinje, ventricular myocardium up to the site of localization of the ventricular vein joint, the ventricular vein itself, atrial myocardium from the area of ​​​​localization of the ventricular vein joint to the AV node. The atrium and ventricle form the upper and lower terminal tracts in this circle. Since this circle is made up of different types of tissue, it can be affected at many levels.

parathas affecting the AV node, accessory atrioventricular tract, ventricular or atrial myocardium. In patients with different locations of the DPVS, there are differences in the atrial part of the reentry circle. If, with right-sided and septal RPVS, the reentry circle includes the inferior septal part of the right atrium, then with left-side RPVS, this part of the atrium, apparently, is not always an obligatory component of the reentry circle. Therefore, it is assumed that some patients with VPU syndrome have entrances to the AV node from the right and left atria.

Depending on the electrophysiological properties of the RPV, AV node, atria and ventricles, only antidromic and/or orthodromic tachycardia may occur in VPU syndrome.

With orthodromic AV reentrant tachycardia, an antegrade propagation of the excitation wave occurs through the AV node into the His-Purkinje system and retrograde propagation through the ventricular vasculature to the atrium. Much less frequently, in only 5-10% of patients with VPU syndrome, a variant of antidromic reentry tachycardia is observed, when the excitation wave makes a circular motion along the same loop, but in the opposite direction: antegrade - through the DPJ, retrograde - through the His-Purkinje system and AV -node to the atrium (Fig. 3).

Ventricular preexcitation tachycardias may also occur in people with atrial tachycardia, atrial flutter, atrial fibrillation (AF), or atrioventricular nodal reentrant tachycardia (AVNRT),

in this case, the DPVS acts as a “witness” (that is, it is not a critical part of the tachycardia circle).

Diagnostic methods

Currently, there are quite a few methods for diagnosing Wolff-Parkinson-White syndrome and determining the localization of DPVS. In the manifesting form of the syndrome in the Scientific Center for Cardiovascular Surgery named after. A.N. Bakulev, as in most cardiac surgery clinics, electrocardiography, surface electrocardiographic mapping and invasive electrophysiological examination of the heart are widely used for these purposes, which will be discussed in this section. At the same time, to diagnose Wolff-Parkinson-White syndrome and determine the localization of RPV, a number of clinics also use vectorcardiography, magnetocardiography, echocardiography, and radionuclide ventriculography. These methods are not more informative, but are more labor-intensive, require the use of special equipment and the work of specialists, and are also not without drawbacks, so they have not been widely used in clinical practice. Diagnosis of pre-excitation syndrome is essentially based on an analysis of the characteristics of the processes of depolarization, repolarization or contraction of the ventricles of the heart that occur during excitation along the DPJ (in sinus rhythm or during an attack of tachycardia) and depending on the location of the additional conduction bundle.

Electrocardiographic diagnostics (ECG in 12 conventional leads)

Historically, the first method for diagnosing VPU syndrome was ECG analysis, which, due to its simplicity and accessibility, became the most widespread.

Currently, the electrocardiographic signs of VPU syndrome include the following:

Shortening of the P-Q interval, which is facilitated by faster penetration of the electrical impulse into the ventricles along the ventricular ventricle; this impulse does not have a delay (pause), unlike the AV node, where the latter reaches at least 120 ms;

Deformation of the beginning of the QRS complex with positive or negative delta waves

noah, which is a reflection of the excitation of part of the myocardium along an additional pathway;

Expansion of the ventricular complex due to the summation of the duration of the delta wave and the main QRS complex;

Displacement of the ST segment and T wave in the direction opposite to the direction of the QRS complex.

For the first time, the types of VPU syndrome (A and B) were described by F.F. Rosenbaum et al. in 1945, based on differences in vector polarity and morphology of the QRS complex in the chest and esophageal leads. Type A was characterized by the presence of an R wave in the right thoracic and esophageal leads, and type B was characterized by the presence of an S wave in at least one of these leads.

Based on the characteristics of the ECG, in particular the direction and magnitude of the delta wave, there are mainly three types of syndrome associated with the localization of RPV.

Type A is characterized by a positive delta wave in lead V1-2. The DPVS between the atrium and the ventricle is located on the left side of the septum; the left ventricle is excited earlier (Fig. 4).

Type B is characterized by a negative delta wave in leads V1-2, but a positive delta wave in leads V4-6. The DPVS is located on the right and, accordingly, the right ventricle is excited earlier (Fig. 5).

Type C has a positive delta wave in leads V1-4 and a negative delta wave in leads V5-6, the RPV is located in the lateral wall of the left ventricle and connects the subepicardial portion of the left atrium with the lateral wall of the left ventricle.

Extensive experience in examining and surgically treating patients with VPU syndrome allowed scientists from Duke University in 1978 to develop and publish an electrocardiographic classification of VPU syndrome. Based on the analysis of the polarity of the delta wave vector 40 ms after the onset of the QRS complex using 12 ECG leads, they identified 10 zones of the location of the RPV along the AV sulcus. This classification is presented in Table 2.

This algorithm has gained very wide popularity and to this day remains a kind of standard for comparison.

When developing diagnostic methods, the problem arose of the practical applicability of various components of the QRST complex for localization

II III aVR aVL aVF

Rice. 4. Electrocardiogram of a 23-year-old woman with VPU syndrome, type A (leads I, II, III, aVR, aVL, aVF, V1-6 of standard ECG)

I II III aVR aVL aVF

Rice. 5. Electrocardiogram of a 26-year-old woman with VPU syndrome, type B (leads I, II, III, aVR, aVL, aVF, V1-6 of standard ECG)

table 2

Algorithm for topical diagnosis of RPV based on delta wave polarity (J.J. Gallagher et al.)

Localization of DPVS I II III aVR aVL aVF V1 V2 V3 V4 V5 V6

anteroseptal + + + (±) - ± (+) + ± ± + (±) + + +

front + + - (±) - + (±) ± (-) ± + (±) + (±) + + +

lateral + ± (-) - - + - (±) ± ± ± + + +

rear + - - - + - ± (+) ± + + + +

paraseptal + - - - (±) + ± + + + + +

posterior paraseptal + - - - + - + + + + + +

rear + - - ± (+) + - + + + + + - (±)

lateral - (±) ± ± ± (+) -(±) ± + + + + - (±) - (±)

front - (±) ± ± ± (+) - (±) + + + + + + +

anterior paraseptal + + + (±) - ± + ± (+) + + + + +

Note. “±” - the initial 40 ms delta waves are isoelectric; “+” - the initial 40 ms delta waves are positive; “-” - the initial 40 ms delta waves are negative.

DPZhS. J.J. Gallagher et al. were subjected to ECG analysis only in cases where the duration of the QRS complex was more than 140 ms. To achieve sufficient severity of the delta wave and a constant degree of fusion of excitation along the RPV and the normal conduction system of the heart, they used endocardial stimulation of the right atrium.

It is noted that with transient VPU syndrome, an ECG without pre-exitation may reveal changes in the T wave, which are preserved due to the phenomenon of “cardiac memory” and depend on the localization of the RPV. The T wave is usually inverted in those leads in which the delta wave is (or was) negative.

The accuracy of most algorithms when identifying 6-7 or more anatomical zones is about 60-70%.

According to the authors, who developed localization methods based on comparison of ECG data and endocardial mapping, verified by successful ablation of RPV, the higher accuracy of diagnosis of RPV during ablation compared to that during open surgery ensures an increase in the accuracy of the proposed algorithms.

Electrocardiographic surface mapping

The method of surface mapping for the purpose of localizing DPHS also began to develop in the 1970s. It consists of registration large quantity unipolar ECG (from 24 to 180 leads are used) from the surface of the torso, followed by analysis of the distribution of electrical potentials. The nature of the distribution of these potentials reflects the internal structure of the electrical generator of the heart. Unlike ECG, the surface mapping method has selective sensitivity to different areas of the heart. Based on a comparison of isopotential maps of surface activation with the results of intraoperative localization of the RPV, leads were found corresponding to one or another anatomical zone of the AV sulcus. IN different jobs From 6 to 17 such zones are identified, but the division of the AV sulcus into 6-7 zones is most often used. When the onset of excitation is localized in one of the zones, a conclusion is made about the location of the DPJ in the corresponding zone of the AV sulcus. However, it is quite difficult to accurately and correctly localize DPHS in practice. Most

a popular criterion is to achieve a certain stable minimum potential. Since the process of registration and processing of information during this method complicated, everything modern systems for surface mapping they operate on a computer base. The accuracy of localization of the DPV by the surface mapping method is quite high and amounts to (with adequate selection of diagnostic criteria) 69-95%.

The surface mapping method, as based on the study electric field hearts, to one degree or another have inherent shortcomings. Most often, difficulties are associated with the presence of a “small” delta wave (QRS complex duration less than 120 ms).

In conclusion, we note that the surface mapping method, despite its complexity and labor intensity, finds, if not widespread, then at least stable clinical application in a number of arrhythmology centers.

Electrophysiological diagnostics

To date, intracardiac electrophysiological study remains the “gold standard” and, according to most authors, a mandatory step in the preoperative topical diagnosis of RPV in patients with cardiac arrhythmias.

If catheter or surgical ablation of additional pathways is indicated;

If a patient with ventricular preexcitation has survived circulatory arrest or suffered unexplained syncope;

If the patient has clinical symptoms in which determining the mechanism of arrhythmia or knowledge of the electrophysiological properties of the DPVS and the normal conduction system can help in choosing the optimal therapy.

In other cases, such as a family history of sudden cardiac death or ventricular preexcitation, but without spontaneous arrhythmias, where knowledge of the electrophysiological characteristics of RPV or the mechanism of inducible tachycardia may help in the selection of appropriate recommendations for further treatment.

Depending on your lifestyle or therapy, as well as if the patient is pre-excited and planning other cardiac surgery, EPS can be performed, but is not mandatory. If an asymptomatic patient has the phenomenon of ventricular pre-excitation on the ECG, but does not belong to the groups described above, EPI is not indicated for him, since most likely this DPVS does not have those electrophysiological characteristics that can support tachycardia, and the patient’s life is not in danger.

Methodology

The main method is direct sequential endocardial mapping of the tricuspid and/or mitral valve rings. During spontaneous or induced (or enhanced) antegrade ventricular preexitation by atrial stimulation, the minimum AV interval and the minimum stimulus-delta interval are determined during mapping. Finding the potential of the so-called Kent bundle serves as evidence that the catheter is located on the DPJ. For better recording, special electrodes were proposed; the use of electrogram (EG) recording with signal averaging for better identification of the “centogram” was also described. The use of additional criteria - analysis of the ratio of the amplitude of spikes A and V, registration of unipolar EG from the distal pole of the catheter - is important during catheter ablation, allowing the ablation electrode to be optimally positioned in the already found localization zone of the DPV. Mapping against the background of orthodromic atrioventricular tachycardia or ventricular pacing is considered not as accurate, but more “convenient”.

In cases where catheter ablation is not planned, the left side of the heart is usually not catheterized. The electrical activity of the left atrium is recorded through an electrode inserted into the coronary sinus. In this case, it is possible to localize all DVCs, except for the left anterolateral ones.

Thus, intracardiac EPI allows for accurate topical diagnosis of RPV with an efficiency of up to 100%. However, the mapping procedure takes a lot of time in general and fluoroscopy time in particular. Problems may arise with the installation of electrodes - for example, catheterization of the

narny sinus is not possible in all cases, especially in children, as well as in patients with concomitant cardiac pathology.

First of all, it is possible to reduce the research time by immediately starting mapping in the area of ​​the expected localization of the DPV, which is determined by one or another non-invasive method.

The current use of multipolar ring-shaped catheters in contact with the entire circumference of the TC ring allows reducing EPI time due to the installation of fewer electrodes (usually two) and synchronous mapping of the entire TC ring. This technique is usually used in patients with manifesting VPU syndrome with right-sided DPJ, but can also be useful in the latent form of VPU syndrome.

Surgery

If we talk about surgical treatment of VPU syndrome as the optimal method for eliminating tachycardia, then during the evolution of the problem, for 20 years, surgeons have used different ways elimination of RPV: indirect methods of getting rid of atrioventricular reentry tachycardias by perinodal discrete cryodestruction of the AV node; partial surgical isolation of the AV node, supplemented by cryodestruction; laser photoablation of the AV node; endocardial RFA of additional pathways on the “open heart”, including the Sealy operation, which was widely used in the elimination of DPVS.

Surgical removal of DPVC relieves attacks of supraventricular tachycardia in patients with VPU syndrome in 95% of cases. Good results are due to reliable clinical diagnosis of this pathology: the characteristic shape of the QRS complex, the development of diagnostic programmed cardiac stimulation, as well as epicardial mapping techniques.

Catheter radiofrequency ablation of additional atrioventricular connections

Direct current catheter ablation and, more recently, radiofrequency energy have been used to treat patients with chronic AV tachycardias, idiopathic

ventricular tachycardia and various types atrial tachycardias with promising results. The effectiveness of the RFA procedure in the treatment of atrioventricular reentry junctional tachycardias is more than 95%.

1) Patients with symptomatic AV-reciprocal tachycardias that are resistant to antiarrhythmic drugs, as well as when the patient is intolerant of drugs or is unwilling to continue long-term drug therapy.

2) Patients with atrial fibrillation (or other atrial tachyarrhythmia) and a rapid ventricular response associated with anterograde impulse conduction along the accessory pathway, if the tachycardia is resistant to the action of antiarrhythmic drugs, as well as if the patient is intolerant of the drugs or is unwilling to continue long-term antiarrhythmic therapy.

1) Patients with AV reentrant tachycardia or atrial fibrillation with a high frequency of ventricular contractions, determined by electrophysiological studies to study the mechanisms.

2) Patients with ventricular preexcitation who have no symptoms, if professional activity, insurance options, peace of mind, or public safety interests will be impaired as a result of the occurrence of spontaneous tachyarrhythmias.

3) Patients with atrial fibrillation and controlled rate of ventricular responses with conduction along an accessory pathway.

4) Patients with a family history of sudden cardiac death.

Patients whose accessory pathway-related arrhythmias respond to antiarrhythmic therapy are easily tolerated, including those who prefer drug therapy over ablation.

Since the early 1990s. There have been reports of the use of RFA in a clinical setting for the treatment of

human heart rhythm disturbances refractory to antiarrhythmic therapy. Since then, many investigators have performed catheter ablation of various animal cardiac structures, including the ventricles, coronary sinus, and tricuspid valve. Radiofrequency ablation turned out to be quite simple to use (does not require general anesthesia), safe (virtually not accompanied by life-threatening complications or mortality) and effective in more than 95% of cases, and in many types of arrhythmias it can achieve 100% results.

Recently, as a result of the achievement of catheter methods for treating arrhythmias high level the need for open surgical interventions for supraventricular tachyarrhythmias resistant to antiarrhythmic therapy, in particular for VPU syndrome, has sharply decreased.

In 1994, E.J. Thompson, evaluating the effectiveness of RFA in the treatment of VPU syndrome, noted that RFA significantly reduces the morbidity, mortality and dependence of such patients on antiarrhythmic therapy (AAT). RFA is the method of choice for patients with VPU syndrome. The procedure is highly effective (95%), mortality is equal to zero.

In recent years, high technologies have been increasingly used in surgical arrhythmology. Thus, non-fluoroscopic mapping systems CARTO and LocaLisa are currently widely used.

There have also been reports of successful use of radiofrequency ablation to eliminate RPV via an epicardial approach.

Atrial fibrillation and VPU syndrome

AF is life-threatening in patients with VPU syndrome. If the accessory pathway has a short antegrade effective refractory period (AERP), then delivering pulses to the ventricles at high rates during AF may result in ventricular fibrillation (VF). Approximately one third of patients with VPU syndrome have AF. DPVCs play a pathophysiological role in the development of AF in this category of patients; most of them are young people who do not have structural heart pathologies. Atrioventricular reciprocal tachycardia (AVRT) with high

Which rhythm frequency may play a role in the induction of AF. Surgical treatments or catheter ablation of the ventricular vein can eliminate AF, as can AVRT.

The incidence of sudden death among patients with VPU syndrome varies from 0.15 to 0.39% during a follow-up period of 3 to 10 years. Cardiac arrest is rarely the first symptomatic manifestation of VPU syndrome. In contrast, in almost half of the cases, cardiac arrest in patients with VPU syndrome is the first manifestation of the syndrome. Considering the potential for the development of AF in patients with VPU syndrome and the risk of sudden death as a result of AF, even low frequency annual cases of sudden death among patients with VPU syndrome and the need for catheter ablation is important.

1) Catheter ablation of the RPV in patients with AF and VPU syndrome with severe symptoms, especially in the presence of syncope due to high heart rate or in patients with a short refractory period of the RPV (evidence level B).

2) Immediate electrical cardioversion to prevent VF in patients with VPU syndrome in whom AF is combined with high heart rate and hemodynamic instability (level of evidence B).

3) Intravenous administration of procainamide or ibutilide in an attempt to restore sinus rhythm in patients with VPU in whom AF develops without hemodynamic instability and is associated with wide QRS complexes (more than 120 ms).

Intravenous use of quinidine, procainamide, disopyramide, ibutilide, or amiodarone in stable hemodynamics in patients with AF associated with ventricular vascular disease (evidence level B).

a) if patients with AF develop tachycardia associated with APP conduction with a very high heart rate and hemodynamic instability, immediate cardioversion is required (evidence level B).

Prescription of intravenous beta-blockers, cardiac glycosides, diltiazem or verapamil in patients with VPU syndrome and signs of ventricular preexcitation in AF (evidence level B).

Studies have revealed that from 0 to 0.6% of asymptomatic patients with VPU syndrome die from VF due to the presence of short AERP DPJS - an obvious risk factor, although previously it was assumed that patients with VPU syndrome and short AERP DPJS have a good prognosis and do not need AAT. Ablation of the DPV with a short AER was recommended only for professional reasons - pilots, athletes, etc.

A study of patients with SUD who had suffered cardiac arrest retrospectively identified a number of criteria that can be used to identify patients at increased risk of sudden cardiac death (SCD). These include:

Shortened R-R interval- less than 250 ms with ventricular preexcitation during spontaneous or induced AF;

History of symptomatic tachycardia;

Multiple additional paths;

Ebstein's anomaly.

Reported high frequency SCD in familial VPU syndrome. Familial forms of VPU syndrome are extremely rare. A number of non-invasive and invasive studies have been proposed to help stratify the risk of SCD.

To determine the risk of sudden death in patients with a manifest form of VPU syndrome, it is possible to conduct a test with intravenous administration of procainamide at a dose of 10 mg/kg for 5 minutes with recording of several ECG leads simultaneously to record changes in the ECG resulting from artificial anterograde blockade in DPZhS. If the test is ineffective, this indicates a short AERP of the DPJ (less than 270 ms). However, given the effect of procainamide on conduction in the AV node (prolongation of the AV node AERP) and the likelihood of transient AV blockade, this test must be carried out in a specialized laboratory. By combining various non-invasive tests, it is possible to identify and identify patients with high

risk of SCD due to a relatively short AERP of the DPJ.

The detection of intermittent ventricular pre-excitation syndrome, characterized by the sudden disappearance of the delta wave and normalization of the QRS complex, indicates that RPV has a relatively long refractory period and the occurrence of VF is unlikely. It is believed that non-invasive research methods are inferior to invasive electrophysiological assessment of the risk of sudden death. Therefore, at present, non-invasive methods do not play a serious role in the study of this group of patients.

Conclusion

VPU syndrome is the second most common cause of supraventricular tachycardia in the world, accounting for up to 0.3% of the general population and 0.5% of people with congenital heart disease. The morphological substrate of the VPU syndrome is represented by the DPVS, or the so-called muscle bridges, which exist in addition to the specialized area of ​​the AV connection and are capable of conducting electrical impulses from the atria to the ventricles. The use of highly informative methods for diagnosing VPU syndrome, such as ECG, surface ECG mapping, transesophageal and intracardiac EPI, has made it possible to create several classifications of VPU syndrome for the topical diagnosis of PVHD. Today, intracardiac EPI is the “gold standard” for diagnosing VPU and, according to most authors, a mandatory stage in the preoperative topical diagnosis of RPV. In addition, intracardiac EPS allows one to assess the risk of SCD in a particular patient by determining the duration of AERP of the ventricular vein and identifying the presence of AF. As is known, patients with short AERP have a higher risk of SCD, and the presence of AF in this category of patients increases this risk several times more, being a pathological link in the development of fatal ventricular arrhythmias. Radiofrequency ablation, which is a safe and highly effective method of therapy, is currently considered the “gold standard” for the treatment of VPU syndrome.

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