Treatment of supraventricular tachyarrhythmias

Emergency treatment of paroxysmal supraventricular tachycardia is aimed at interrupting the paroxysm of tachycardia and normalizing hemodynamics.

Stopping the attack begins with vagal tests: upside down, stand on hands, Aschner's test, Valsalva test, carotid sinus massage, pressing the root of the tongue. In young children, the most effective is upside down for a few minutes.

The tactics of emergency medication depend on the electrophysiological substrate of paroxysmal supraventricular tachycardia. Emergency therapy of paroxysmal supraventricular tachycardia with a narrow QRS complex and also with a wide QRS as a result of functional blockade of the bundle of the bundle are started with intravenous adenosine phosphate (1% solution in / in strumno: up to 6 months - 0.5 ml, from 6 months to 1 year - 0.8 ml, from 1 to 7 years - 1 ml, 8-10 years - 1.5 ml, over 10 years - 2 ml). If the ineffectiveness of the introduction can be repeated twice more with an interval of at least 2 minutes. Adenosine phosphate slows down through the AV node, interrupts the re-entry mechanism and helps restore sinus rhythm. The drug can cause cardiac arrest, so it should be administered under conditions that allow resuscitation if necessary. With the ineffectiveness of a triple adenosine injection of phosphate injected antiarrhythmic drug class IV verapamil (0.25% solution iv / slowly in a dose of 0.1-0.15 mg / kg). With the preservation of tachycardia, intravenous administration of a preparation of class III amiodarone is recommended. The drug is very effective in preventing development and arresting ventricular fibrillation. It has a long half-life (from 2 to 10 days). The peak concentration of the drug in the blood is reached within 30 minutes. If necessary, the drug can be administered for several days (not more than 5 days). In paroxysms of atrial flutter, ectopic and ge-entry-atrial tachycardia, ortodromic AV-reciprocal tachycardia, arrest of an attack in older children (7-18 years) is possible by administering procainamide attributable to 1a class of antiarrhythmic drugs (10% IV solution slowly in dose 0.1-0.2 ml / kg). The administration is carried out under the control of ECG and BP data and is stopped with a sharp drop in blood pressure, the appearance of a progressive expansion of the ventricular complex on the ECG. In the presence of conditions, it is possible to stop an attack by radiofrequency catheter destruction of the arrhythmogenic zone. This type of non-drug treatment is performed under conditions of X-ray surgery.

Emergency antiarrhythmic therapy of paroxysmal supraventricular tachycardia with a wide complex of QRS (antidromic tachycardia) includes preparations of I class (procainamide) and aimalin close to them by electrophysiological properties. Reducing the rate of depolarization, increasing the duration of repolarization, refractory periods in the atria, ventricles, additional ways of conducting [2.5% IV solution at a dose of 1 mg / kg (1-2 ml) slowly for 7-10 minutes in 10 ml isotonic solution of sodium chloride]. Drugs are administered under the control of ECG and BP data, administration is discontinued with the appearance of progressive intraventricular delay, ECG phenotype of Brugada syndrome. Prolonged hemodynamically significant antidromic paroxysmal supraventricular tachycardia, as well as attacks of atrial flutter with additional atrial-ventricular connections, are indications for an emergency radiofrequency catheter destruction of an abnormal additional AV compound.

In order to create favorable conditions for the drug-induced paroxysm of tachycardia, immediately after the development of paroxysm, sedatives, aminophenylbutyric acid (a tranquilizer of the phenibut that exerts a sedative, anxiolytic action and possessing elements of nootropic activity), and carbamazepine (possesses antidepressant, membrane stabilizing and antiarrhythmic action due to inactivation of the incoming sodium current). The purpose of these drugs is especially important in cases when the attacks of tachycardia in children are accompanied by a pronounced psychoemotional agitation and have a vegetative color. With prolonged, prolonged seizure, the introduction of diuretic drugs is recommended. In cases of ineffectiveness of complex medicamentous therapy, the increase of heart failure is shown the conducting of transesophageal stimulation and cardioversion to 2 J / kg.

Rational therapy of paroxysmal supraventricular tachycardia during the interictal period influences the neurogenic basis of arrhythmia, contributing to the restoration of the neurovegetative balance in the regulation of the heart rhythm. Nootropic and nootropic drugs [gamma-aminobutyric acid (aminalon), glutamic acid] exert a trophic influence on vegetative regulation centers, enhance metabolic activity of cells, mobilize energy reserves of cells, regulate cortical-subcortical relationships, exert a mild and persistent stimulating effect on sympathetic regulation heart. With psychoemotional disorders, aminophenylbutyric acid (phenibut) is prescribed, which has a sedative, anxiolytic effect and possesses elements of nootropic activity. In paroxysmal supraventricular tachycardia in children, the long-term administration of classical antiarrhythmic drugs has significant limitations and adversely affects the long-term prognosis of paroxysmal supraventricular tachycardia.

In cases where tachycardia is persistent and there is a need to connect classical antiarrhythmic drugs, radiofrequency catheter ablation is the method of choice. In determining the evidence, one should adhere to reasonable conservatism in young children, which is associated with a high probability of a spontaneous disappearance of a rhythm disorder by 8 months of age. However, in 30% of them, the arrhythmia subsequently recurs, which leads to the need to observe and decide on further treatment tactics. In children under 10 years of age, the risk of complications with interventional treatment is higher than in the older age group. In children older than 10 years, indications for interventional methods of treatment of tachyarrhythmias are comparable to those for adult patients. The effectiveness of radiofrequency ablation of supraventricular tachycardia is, according to different authors, from 83 to 96% and depends on the type of arrhythmia, technical capabilities and experience of the clinic. With frequent paroxysmal supraventricular tachycardia (monthly seizures) and the inability to perform interventional treatment of arrhythmia (small age of the patient localization of the electrophysiological substrate in close proximity to the structures of the conduction system of the heart or epicardial), an antiarrhythmic effect can be exerted by an anticonvulsant drug carbamazepine (at a dose of 5-10 mg / kg per day in 2-3 doses for a long time), which has antidepressant, membrane stabilizing and antiarrhythmic effect due to inactivity novation incoming sodium current. In children of preschool age, with frequent and / or hemodynamically unstable attacks of paroxysmal supraventricular tachycardia on the background of pharmacological basic therapy and inefficiency of carbamazepine (finlepsin), it is possible to prescribe antiarrhythmic drugs: amiodarone or propafenone.

The goals of rational drug therapy for non-paroxysmal supraventricular tachycardia are correction of neurovegetative disorders that contribute to the functioning of abnormal electrophysiological mechanisms of myocardial stimulation (basic therapy), and direct effects on the electrophysiological substrate of arrhythmia (antiarrhythmic drugs). Basic therapy contributes to the restoration of the protective function of the sympathetic-adrenal system and has a trophic effect on vegetative regulation centers, restoring the balance of vegetative regulation of the heart rhythm, displaced in children with non-paroxysmal supraventricular tachycardia, in the direction of relative predominance of parasympathetic influences. For this purpose, children with non-paroxysmal supraventricular tachycardia are prescribed nootropic and vegetotropic drugs with a stimulating action component (gamma-aminobutyric acid (aminalon), glutamic acid, pyrithinol (pyriditol).] Neurometabolic stimulants have anti-asthenic, sympathomimetic, vasovegetative, antidepressant and adaptogenic (improve tolerance to exogenous stressors) .In children with non-paroxysmal supraventricular tachycardia, these drugs are prescribed (the total duration of the first course is 6 months.) With a significant decrease in the severity of arrhythmia after the first course, a second course is scheduled for 3 months If there are signs of diastolic myocardial dysfunction according to EchoCG, disturbances of the repolarization process according to ECG data, stress tests, metabolic therapy, antihypoxants and antioxidants, vitamins and vitamin-like agents, macro- and microelements are prescribed for this purpose: levokarnitin inside 50-100 mg / day for 1-2 months, kudesan inside 10-15 drops a day for 2-3 months. Actovegin in / m 20-40 mg for 5-10 days.

Indications for interventional treatment of children with non-paroxysmal supraventricular tachycardia are non-paroxysmal, recurrent (continuously-recurrent) over-ventricular tachycardia of various genesis with the development of arrhythmogenic myocardial dysfunction in children of any age, with ineffective drug therapy and no contraindications to intervention therapy. Indications for the appointment of classical antiarrhythmic therapy (antiarrhythmic drugs I-IV classes) are similar to those for interventional treatment. That is why the appointment of antiarrhythmic drugs is possible only if there are contraindications to the interventional treatment. Methods of interventional treatment of supraventricular tachycardia are generally accepted. It is important for children to use the most sparing protocol of radio-frequency influences.

In paroxysmal supraventricular tachycardia, the efficacy of drug-based basal therapy is assessed no earlier than 3-6 months. Positive dynamics from the side of symptoms appears consistently and has certain regularities. Initially there is a change in circadianity in the occurrence of tachycardia attacks: the most unfavorable night and evening paroxysms are replaced by day or morning. Then the character of relief of attacks of supraventricular tachycardia changes: seizures previously stopping only against the background of intravenous antiarrhythmic drugs become susceptible to cupping with vagal samples. And, finally, there is a decrease in the duration and frequency of seizures, followed by the disappearance of paroxysms.

The effectiveness of radiofrequency catheter ablation is assessed intraoperatively on the basis of special electrophysiological criteria, as well as in the early and late postoperative period on the basis of the disappearance of seizures, both in the early and late period, and the inability to provoke the appearance of paroxysm of tachycardia of the former morphology during the special transesophageal atrial stimulation protocol. The study is conducted no earlier than 3 months after the intervention. In cases of interventional treatment, when exposed in an area close to the anatomically normal structures of the normal cardiac conduction system, a complete transverse blockage may occur, which will lead to the need for an implantation of the pacemaker. The probability of developing this complication with modern technologies for carrying out this procedure is small. When localizing the electrophysiological substrate of supraventricular tachycardia subepicardially, in the immediate vicinity of the structures of the main cardiac conduction system, of the coronary arteries, the procedure for radiofrequency catheter ablation can be regarded as inappropriate because of the risk of complications. In these cases, the main emphasis should be placed on drug therapy - a combination of basic and antiarrhythmic therapy, if the treatment is ineffective, the prognosis is regarded as unfavorable.