Paroxysmal tachycardia in children

This type of heart rhythm disturbance is understood as a sudden, sharp increase in cardiac rhythm, manifested as specific changes in the ECG, lasting from a few seconds to many hours (sometimes days) with a characteristic sudden termination of the attack and normalization of the rhythm.

Paroxysmal tachycardia of childhood is a fairly common type of arrhythmia, occurs with a frequency of 1: 25,000 children. Among other types of heart rhythm disturbances, paroxysmal tachycardia is detected in 10.2% of all arrhythmias.

Paroxysmal tachycardia is a violation of the rhythm of the heart, which is manifested by sudden palpitations with specific electrocardiographic manifestations (heart rate more than 150-160 per minute in older children and more than 200 in younger children), lasting from several minutes to several hours.

[1], [2], [3], [4], [5], [6]

Causes of paroxysmal tachycardias:

• disorders of vegetative regulation of the heart rhythm;
• organic heart damage;
• electrolyte disturbances;
• psychoemotional and physical stress.

Paroxysmal tachycardia in most cases occurs in children who do not have organic damage to the heart, and is regarded as the equivalent of a panic attack. In the age aspect, seizures of paroxysmal tachycardia are noted in both older children, adolescents, and infants. The maximum frequency of seizures is established at the age of 4-5 years.

Intracardiac mechanisms for the initiation and implementation of an attack of paroxysmal tachycardia have been studied in sufficient detail. The electrophysiological basis of paroxysmal tachycardia is the emergence from the sinoatrial, atrioventricular node or atrium of a circular wave (ri-entri) or a sharp increase in self-automatism in the ectopic focus.

[7], [8], [9], [10], [11], [12]

Symptoms of paroxysmal tachycardia

Clinically, in children with paroxysmal tachycardia attacks, both pre-positional and provoking factors are noted. Adverse during the period of pregnancy and childbirth is noted in almost all mothers. As a rule, in families of children with paroxysmal tachycardia, the percentage of people with autonomic dysfunction, psychosomatic diseases, and neuroses is high.

Features of the constitution, the structure of the conduction system of the heart can serve as the basis for the development of paroxysmal tachycardia. The existence of additional ways of conducting (DPP) contributes to the emergence of WPW syndrome, predisposing to attacks of paroxysmal tachycardia and weighting them. In WPW syndrome paroxysmal tachycardia attacks occur in 22-56% of children, which confirms the importance of a thorough ECG study of this category of patients. In general, the presence of foci of chronic infection (chronic tonsillitis, chronic diseases of the paranasal sinuses, etc.), dyshormonal disorder (delay in puberty, in girls irregular menstruation, etc.), diskinetic manifestations from the side gastrointestinal tract and biliary tract. Body weight of children with paroxysmal tachycardia, as a rule, is within the norm, but often there are children with a reduced mass, especially aged 10-12 years.

In a neurological status, 86% have separate organic micro-signs. In 60% of children, signs of hypertension-hydrocephalic syndrome are revealed. Children have a pronounced vegetative lability of the vasomotor apparatus, which is manifested by persistent, red spilled dermographism, acrohyperhidrosis of the brushes, and strengthening of the vascular pattern of the skin. In the vegetative status, the majority have a vagotonic initial tone, hypersympathic-tonic reactivity. Vegetative maintenance of the activity, as a rule, is insufficient, manifested in the hyperdiastolic version of the wedge-orthostatic test.

In general, we can talk about the lack of sympathetic autonomic nervous system in patients with paroxysmal tachycardia, which is associated with an increased parasympathetic tone.

Anxious-depressive and phobic experiences are a characteristic component of the mental status of this group of patients. This is especially true for older children, who have a fairly long experience of unsuccessful treatment of attacks of paroxysmal tachycardia, especially if they occur frequently, and intravenous injection of antiarrhythmic drugs by an ambulance team is necessary to stop them. In addition to mental trauma of this kind, the microsocial environment of a child with paroxysmal tachycardia is very often unfavorable (incomplete families, chronic alcoholism of parents, conflicts in the family, etc.), which contributes to the formation of a pathocharacterological anxiety radical personality.

The most characteristic manifestations are noted during the paroxysm of paroxysmal tachycardia. The paroxysmal tachycardia attack predominantly occurs against the background of emotional stress, and only 10% of the provoking factor is physical activity. Some children may have a premonition of an approaching attack. Most children of the senior, adolescence absolutely accurately determine the time of onset and end of the attack. The paroxysmal tachycardia attack is accompanied by noticeable changes in hemodynamics: impact shock is reduced, peripheral resistance is increasing, resulting in deterioration of the regional blood supply to the brain, heart, and other internal organs, accompanied by painful, painful sensations. During an attack of paroxysmal tachycardia, attention is drawn to the increased pulsation of the cervical vessels, pallor, sweating of the skin, slight cyanotic lips, mucous membranes of the oral cavity, possibly raising the temperature to subfebrile digits and chill-like hyperkinesia. After an attack, a large amount of light urine is released. The child's reaction to the onset of an attack is determined by his age and emotional-personal characteristics. Some children suffer an attack of tachycardia rather calmly, they can continue to practice their usual affairs (play, read). Sometimes only careful parents can catch on some subjective signs the presence of short attacks of paroxysmal tachycardia. If the attack is prolonged (hours, days), then the well-being of children noticeably worsens. Patients are attracted by anxious behavior, anxiety, complain of a strong tachycardia ("the heart jumps out of the chest"), a feeling of pulsation in the temples, dizziness, weakness, dark circles in the eyes, a feeling of lack of air, nausea, urges to vomit.

Some children have developed skills that help to stop an attack using breathing delay and straining (i.e., vagal reflexes), sometimes vomiting helps, after which the attack stops. In 45% of children attacks occur in the evening and night hours, in 1/3 - only in the afternoon. The most severe are evening attacks of paroxysmal tachycardia. The average duration of an attack is 30-40 minutes.

It is necessary to make a differential diagnosis between chronic (non-paroxysmal) tachycardia and paroxysmal tachycardia, if the paroxysm of tachycardia lasts several days. The first attack of paroxysmal tachycardia is self-cured in 90% of cases, repeated ones - only in 18%. In stopping the paroxysmal tachycardia attack, use vagal tests (eye-heart reflex, Valsalva's test, Tom-Roux's solar reflex - pressure of the fist clenched in the area of the solar plexus). Worse are paroxysmal tachycardia attacks in children who have an extended QRS complex on the ECG during an attack, with regional hemodynamic disorders being possible with this option.

Changes in the secondary ECG due to a decrease in stroke volume with paroxysmal tachycardia and worsening of coronary blood flow can be noted even several days after the attack. On the EEG, 72% show signs of insufficiency of the mesodiencephalic structures of the brain with a decrease in the threshold of convulsive readiness when provoked by 66%. There is no epileptic activity.

Types of paroxysmal tachycardia

Most authors distinguish two main forms of paroxysmal tachycardia: supraventricular (supraventricular) and ventricular.

• Paroxysmal supraventricular tachycardia. In children, in most cases, they are of a functional nature, often arise as a result of changes in the vegetative regulation of cardiac activity.
• Ventricular paroxysmal tachycardia. They are rare. They are classified as life-threatening states. As a rule, they arise against the background of organic heart diseases.

To diagnose an attack of paroxysmal tachycardia, the following criteria are used:

1. heart rate more than 200 in 1 min in small children and more than 150 in 1 min in older children and adolescents, while the rhythm is stable;
2. unusual different from sinus tooth P;
3. paroxysmal is the presence of at least 3 contractions in a row;
4. the ventricular complex of QRS is preceded by the tooth P;
5. the PR interval is usually normal or elongated;
6. Secondary changes in ST-T are noted;
7. the use of vagal samples (Dagnini-Aschner, a solar reflex) leads to an end to the attack (in the ectopic version of paroxysmal tachycardia, the effect is often absent).

Treatment of paroxysmal tachycardia

Paroxysmal supraventricular tachycardia

In the treatment of paroxysmal supraventricular tachycardia, vagal tests are performed, prescribe medications that affect the central nervous system, and antiarrhythmic drugs.

• Vagal tests (reflex action on the vagus nerve).
• Massage of the carotid sinus. Each sinus is alternately affected by 10-15 seconds, starting with the left as a more rich end of the vagus nerve.
• Valsalva test - straining at maximum inspiration with a delay of breathing for 30-40 seconds.
• Mechanical irritation of the pharynx - provocation of the vomiting reflex. In younger children, these procedures are replaced by a strong pressure on the stomach, which often causes reflex reflexes or reflex "diver." This complex reflex can also be caused by the irritation of the head and (or) the face of the child with ice water. It is necessary to be ready for the treatment of severe bradycardia and even asystole, which can arise due to a sharp increase in the tone of the vagus nerve with a similar interruption of supraventricular arrhythmias.
• Drugs affecting the central nervous system.

The arrest of paroxysmal supraventricular tachycardia should begin with the appointment of drugs that normalize the cortical-subcortical relationship. It is possible to appoint Phenibutum (from 1/2 to 1 tablet), carbamazepine (10-15 mg / kg per day), tincture of valerian (1-2 drops per year of life), peony tincture (1-2 drops per year of life), tincture hawthorn (1-2 drops per year of life), as well as potassium and magnesium preparations (potassium and magnesium asparaginate).

• Antiarrhythmic drugs

If the above therapy is ineffective after 30-60 minutes, antiarrhythmic drugs are prescribed, which are applied sequentially (with no effect on the previous one) at an interval of 10-20 minutes. First recommend to apply 1% solution of trifosadenin without dilution at an age dose of 0.5 mg / kg intravenously struino quickly (2-3 seconds). If necessary, the drug can be re-entered in a double dose after 5-10 minutes. If the QRS complex is narrow on the electrocardiogram, and the use of trifosadenin did not lead to an end to the attack, it is recommended to use a 0.25% solution of verapamil intravenously on a 0.9% solution of sodium chloride at a dose of 0.1-0.15 mg / kg. Contraindications for his appointment include atrioventricular blockade, arterial hypotension, Wolff-Parkinson-White syndrome, severe breach of myocardial contractility, and beta-blockers. If necessary, after verapamil with supraventricular tachycardia, 0.1-0.3 ml of 0.025% digoxin solution is slowly injected intravenously.

The termination of an attack of supraventricular tachycardia can be achieved with beta-blockers (propranolol is prescribed in a dose of 0.01-0.02 mg / kg with its increase to a maximum total of 0.1 mg / kg, esmolol - at a dose of 0.5 mg / kg and others intravenously). However, in children the drugs of this group are rarely used.

• Paroxysmal tachycardia with wide QRS complexes

Coping of an attack of a tachycardia after the use of trifosadenin is first carried out with giluritmal, amiodarone or procainamide together with phenylephrine, and only in the absence of effect lidocaine is used as a 1% solution intravenously slowly in 5% dextrose solution at the rate of 0.5-1 mg / kg.

• Treatment if the electrocardiogram can not be recorded

Intravenous slow administration of a 2.5% solution of giluritmal at a dose of 1 mg / kg was shown. In addition, a 5% solution of amiodarone is administered intravenously slowly on a 5% dextrose solution at a dose of 5 mg / kg. In the absence of the effect, 10% solution of procainamide is slowly introduced intravenously on a 0.9% solution of sodium chloride from the calculation of 0.15-0.2 ml / kg with simultaneous intramuscular injection of 1% phenylephrine solution at a dose of 0.1 ml per year of life.

• Electropulse therapy

If the medication is ineffective, the attack persists for 24 hours, and when signs of heart failure increase, electropulse therapy is performed.

The prognosis for paroxysmal tachycardia is good, unless, of course, the organic defeat of the heart is attached. Treatment of paroxysmal tachycardia, in addition to the attack, when antiarrhythmic drugs are used (in the case of failure of the reflex action by vagal tests), are performed during the interictal period. Effectively, the use of finlepsin (in the age-related dose) in combination with psychotropic (sedative) drugs, the appointment of acupuncture, vegetotrophic drugs, psychotherapy.