Non-paroxysmal tachycardia in children

Non-paroxysmal tachycardia refers to widespread heart rhythm disturbances in children and occurs in 13.3% of all arrhythmias. In the category of chronic carry tachycardia in the case of its existence in the patient over 3 months. Contract (with chronic sinus) and more than 1 month. - with tachycardia, which is based on an abnormal electrophysiological mechanism. The pulse rate with non-paroxysmal tachycardia 90-180 in 1 min, there is no sudden onset and end. Significantly more rare in children are ventricular and chaotic tachycardia.

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What causes non-paroxysmal tachycardia in children?

Non-paroxysmal tachycardia can occur in acute and chronic heart diseases - myocarditis, rheumatism, heart defects. The appearance of this kind of arrhythmias due to severe metabolic disturbances, hypoxia, ischemia in the heart muscle is characteristic mainly for adult age, and in children with non-paroxysmal tachycardia this cause of arrhythmia is much sharper. It is shown that at the heart of this kind of arrhythmias lies the change in the functioning of the conduction system of the heart (PSS), responsible for the formation and propagation of impulses.

What happens with non-paroxysmal tachycardia in children?

The universally recognized cardiac mechanism of non-paroxysmal tachycardia is based on the concept of ectopic focus, re-entry of excitation and trigger activity. Myocardial fibers under certain conditions exhibit the ability to spontaneously generate depolarizing pulses, thus acquiring the properties of pacemakers. For the propagation of excitation through the myocardium, it is necessary to have pathways that are functionally isolated from the rest of the heart: additional conducting paths (DPT) (bundles of Kent, Maheima, etc.). There was a high incidence of DPP in non-paroxysmal tachycardia in persons with systemic connective tissue disorder (Marfan's disease, Ehlers-Danlos syndrome and other hereditary diseases). The importance of genetic factors is emphasized by the description of family cases.

However, the findings of detection of DPP in healthy individuals without any arrhythmias suggest that the anomaly of the conduction system of the heart is a condition for development, and not the cause of non-paroxysmal tachycardia. The same rhythm disturbance is based on a change in the neurohumoral regulation of the heart, noted in 87% of patients and realized through vagosympathetic influences. It has been established that non-paroxysmal atrioventricular tachycardia in children without signs of organic damage to the heart is the result of a change in the functional state of the cerebral structures, which through the disturbed vegetative regulation leads to tachycardia.

There is no generally accepted classification of chronic non-paroxysmal tachycardia. Three main clinical and pathogenetic variants of non-paroxysmal tachycardia are distinguished: sinus, recurrent heterotopic and constant, differing in character and degree of manifestation of disorders from the autonomic and central nervous system. All children with non-paroxysmal tachycardia have a psycho-vegetative syndrome of varying severity.

Symptoms of non-paroxysmal tachycardia in children

Chronic sinus tachycardia (HST) in girls is more common than in boys. Duration of the disease until the diagnosis is correct - from 6 months. Up to 6 years. These children are noted for the unfavorable course of the perinatal and postnatal period (70%), a high infectious index (44.8), unfavorable stressing circumstances in their surroundings (single parent family, parents' alcoholism, school conflicts, etc.). In addition to environmental, family features are noted in children with sinus tachycardia: increased concentration in the pedigree of psychosomatic diseases of the ergotrophic orientation (hypertension, IHD, diabetes, thyrotoxicosis, etc.), and in 46% of cases, sympathetic-tonic reactions with parents and siblings side cardiovascular system (increased blood pressure, frequent heart rate, etc.).

Chronic tachycardia can be an accidental finding during examination, especially if the child does not make complaints. As a rule, all children subjectively tolerate tachycardia. Among frequent complaints fatigue, excitability, pain in the abdomen and legs, dizziness, headache, cardialgia prevail. In children with chronic sinus tachycardia, attention is drawn to the asthenic constitution, decreased body weight, pallor of the skin, anxiety. Neurological symptoms are represented by individual organic micro-signs, manifestation of compensated hypertensive-hydrocephalic syndrome. According to the combined clinical data and the results of vegetative sampling, these children are diagnosed with mixed-type vegetative dystonia syndrome in 56% and sympathetic syndrome in 44%. In 72.4% of children with echocardiography, prolapse syndrome and mitral valve dysfunction due to autonomic dysregulation are noted.

It is important to note that 60% of children with chronic sinus tachycardia in their time were observed in psychoneurologists about tics, stuttering, nightly fears, headaches. Children of this group are characterized by high emotional instability, anxiety, increased aggression. In the intersocial contacts, the zone of their adaptation is sharply narrowed, they experience discomfort in almost half of all possible normal life situations, which is accompanied by anxious and depressive neurotic reactions. On the EEG, there are irregular changes in the form of irregular, low-amplitude alpha-rhythm, smoothening of zonal differences. There are signs of increased activity of mesencephalic structures.

Thus, chronic sinus tachycardia occurs in children with autonomic dystonia, a feature of which is the presence of a hereditary predisposition to sympathetic reactions of the cardiovascular system against the background of a protracted neurotic condition. Peripheral mechanisms of arrhythmias are that the acceleration of the automatism of the sinus node is achieved through hyperkatecholamineemia (50%) or through the hypersensitivity of the sinus node to catecholamines (37.5%), less often when hypovaginating (14.3%).

How is non-paroxysmal tachycardia diagnosed in children?

Heterotopic chronic tachycardia of functional genesis in 78% of cases is detected accidentally during medical examination. Ignorance of this form of vegetative cardiac rhythm disruption in 54.8% of the examined children was the reason for erroneous diagnosis of the myocardium, rheumatism with the appointment of hormones, antibiotics without any effect, which led to unjustified restrictions on the regime, neurologization of children. The peculiarity of the ECG of this kind of arrhythmia is the presence of two types of rhythm disturbance: a permanent form of non-paroxysmal tachycardia, in which the ectopic rhythm is not interrupted by sinus contractions (chronic tachycardia of the permanent type - XNTPT), and recurrent - when ectopic contractions alternate with sinus (the so-called chronic non-paroxysmal tachycardia of recurrent type - KHNTVT). The transformation of the constant form of chronic tachycardia into a recurrent and, in turn, transition of non-paroxysmal tachycardia to paroxysmal, indicates the presence of common pathogenetic links of these rhythm disturbances.

Treatment of non-paroxysmal tachycardia in children

In contrast to the organic forms of rhythm disturbance, treatment of non-paroxysmal tachycardia with antiarrhythmic drugs in 81% of cases is completely unsuccessful. Like sinus, heterotopic tachycardia without treatment can exist for many years. However, prolonged tachycardia (especially at high heart rate) can lead to arrhythmogenic cardiomyopathy (in the form of myocardial hypertrophy, increase in heart size, decrease the contractile capacity of the heart muscle) and even heart failure. Thus, arrhythmias in children with vegeto-dystonia are far from a safe manifestation, in need of timely and correct correction.

In this group of patients, no gender predominance was noted. Attention is drawn to the lag in the physical development of patients (85%) - 2-3 years against the age standard, the delay in puberty (75% of children) - in girls over 10 years and in boys over 12 years.

Early history of children with KHNTVT and KHNTPT differs little from the group of children with non-paroxysmal tachycardia in the frequency of pathology, but more often there is prematurity, the percentage of asphyxiated disorders in labor is higher (chronic sinus tachycardia 28%, heterotopic tachycardia 61%). When studying a family history, the trophotropic orientation of diseases in relatives of children (84%), especially arterial hypotension, is revealed.

Children with this type of chronic non-paroxysmal tachycardia with an external appearance significantly differ from children with chronic sinus tachycardia: as a rule, they are flaccid, asthenic children with normal or overweight, presenting numerous complaints of anxious-depressive and hypochondriacal content. Despite the fact that in general the frequency of psychotraumatic situations in this group of children is sharp, they have their own specificity in the form of pathological forms of upbringing - with the child's hyper-socialization, education in the "cult of sickness," in families with an anxious-phobic type of parents, the formation of the iatrogenic principle in the structure of the child's disease.

Expressed autonomic dysfunction was noted in all children with heterotopic tachycardia, while in 86% of cases with CNTT and 94% - in CHDTTT there is a developed syndrome of vegetative dystonia, while the remaining children have autonomic lability. By the vegetative tone more than half of the children are parasympathetic influences, in 1/3 children - mixed tone. Vegetative maintenance of activities was inadequate in 59% of children with CNTT and in 67% of cases with CNTPT. This indicates a functional deficiency of the sympathetic-adrenal system, which is confirmed by biochemical indicators.

Children with heterotopic tachycardia often have various neuropsychiatric abnormalities: stuttering, enuresis, tics, delay in the formation of psychomotor skills, convulsive syndrome. Neurological examination in more than 85% of children showed microorganism, similar to that found in other forms of vegetative dystonia, but it is more distinct, combined with signs of hypertensive hydrocephalic syndrome in 76% of patients.

Children with this type of tachycardia are characterized by high anxiety, difficulties of adaptation in school, among peers, and the presence of conflicts, as a rule, is predetermined by the existence of the disease and the attitude of the child towards it. In children of this group, the formation of the internal picture of the disease is associated with hypertrophied ideas about the dangers of arrhythmia for life, a prolonged hypochondriacal "elaboration" of neurotic information. The use of EEG in children with heterotopic tachycardia showed the presence of functional shifts, characterized by an increased presence of slow-wave oscillations (6-8-range), a general immaturity of rhythm. Electrophysiological changes reflect the dysfunction of the diencephalic stem structures of the brain and in children older than 11 years indicate a delay in the morphofunctional maturation of cortical-subcortical relationships. The functional state of the brain is characterized by insufficient mobilization of the activation systems entering the limbic-reticular complex. Given the features of cerebral organization of children with heterotopic tachycardia, the presence of signs of partial delays in maturation, the existence of autonomic dysfunction with a predominance of the parasympathetic link and pronounced neurotic personality changes, a basic therapy that takes into account these features, including stimulant effects on metabolism (pyriditol, glutamic acid, etc.), psychotropic and vascular agents.