Arrhythmias in children and their treatment

Relatively frequent cause of circulatory failure in pediatric practice is the development of various variants of heart rate abnormalities - arrhythmias in children. It is known that the pacemaker cells of the sinoatrial (CA) node have the highest activity in pulse generation, which is the source of impulse formation or first-order automatism.

Pacemaker cells located in the atria, atrioventricular (AB) junction, the Gysa system, refer to the centers of automatism of the 2nd and 3rd order. Normally, they are suppressed by impulses originating from the CA node, but under certain circumstances they can take the lead, causing disturbances in the rhythm of the heart contraction and reducing the effectiveness of its pumping function, so arrhythmias can cause OCH.

[1], [2], [3], [4], [5], [6], [7], [8], [9]

Symptoms of arrhythmia in children

When arrhythmia occurs in children, they complain of increased heart rate, anxiety, weakness. Violated not only the rhythm of the heart, but also blood circulation (lowering blood pressure, microcirculation disorders). Often arrhythmias in children are detected accidentally during medical examination, as patients do not experience painful sensations. Particular attention is caused by arrhythmias accompanied by circulatory failure, hypoxic encephalopathy (for example, in the form of Morganyi-Adams-Stokes attacks with complete AV blockade). Significant effects on blood circulation also have stable, serial ventricular extrasystoles (bigeminy, triheminia), AV- and ventricular tachycardia, fibrillation and flutter of the ventricles, tachiiformes of atrial fibrillation.

What are the arrhythmias in children?

The conventional classification of arrhythmia in children does not yet exist, but we can use the classification of AP Meshkov (1996), in which two groups are formed according to the source of pulse generation:

1 st group - nomotopic arrhythmias in children (from the CA node): 

• sinus tachycardia, 
• sinus bradycardia.

2nd group - ectopic arrhythmias in children (other sources of impulses):

• passive (replacing the absence of pulses from the CA node): 
  • slow AV-rhythm, 
  • slow idiopathic (ventricular) rhythm;
• Active (manifesting, in addition to impulses from the CA node, competitively): 
• accelerated ectopic rhythms emanating from different parts of the heart,
  • extrasystole and parasystole,
  • flicker and flutter of the atria,
  • flicker and flutter of the ventricles.

Arrhythmias in children of the 1st group arise, as a rule, as a result of changes in the vegetative regulation of the heart (neuroses, stresses, etc.), in connection with which they are also called functional arrhythmias. The second group relates to the organic nature of arrhythmias associated with toxic, inflammatory or morphological lesions of the heart. Organic arrhythmias include rhythm disturbances in Wolff-Parkinson-White syndrome (WPW), weakness syndrome of the CA node, and other variants of premature ventricular excitation. In their genesis, additional (shunting) ways of conducting the pulse from the atria to the ventricles, bypassing the CA node (Kent, James, etc.) play an important role. ECG signs of these anomalies are the shortening of the segment PQ <0.09 s, the presence of a sigma wave on the ascending knee with broadening of the ARS complex and a decrease or inversion of the T wave.

Treatment of arrhythmia in children

The determination of the pulse helps in the diagnosis of arrhythmias, although an accurate diagnosis is possible only when recording and analyzing the ECG.

There are paroxysmal and chronic arrhythmias in children. By paroxysmal rhythm disturbance is understood as the sudden appearance and disappearance. A distinctive feature of paroxysmal supraventricular tachycardia (PNT) is the presence on the ECG of a correctly located tooth P and a narrow (<0.12 sec) QRS tooth. The diagnosis is established if there are more than 3 complexes on the ECG with a heart rate of 120 to 300 per minute. In children, sinus PNT is more common. With AB-node PNT, the P-wave may be in front of the complex (2N8 (the source of the rhythm in the upper part of the AV node), merge with it or follow it (in the middle and lower part of the node, respectively) .PHT only reflex therapy methods to the cheek, one-sided irritation of the carotid sinus, reflexes of Aschner, Valsalva - straining, vomiting.) Beta-blockers are effective intravenously slowly. You can use novocainamide (at a dose of 5 mg / kg) with mezaton (0.1 ml for each year of life; not more than 1 ml) to prevent possible arteries cial hypotension.

You can use cordarone in a dose of 8-10 mg / kg-day) in 2-3 oral administration for 5-6 days, followed by a decrease in the dose in 2 times. During the admission and 15-20 days after the withdrawal of the cordarone, paroxysmal tachycardia attacks are not repeated. Unfortunately, this drug has a number of side effects that limit its long-term use (for example, the development of fibrosing alveolitis, hypothyroidism or thyrotoxicosis).

Cardiac glycosides (digoxin at a saturation dose of 0.05 mg / kg with the introduction of it fractional for 24-36 h) are used in the treatment of supraventricular tachycardia in children. Usually, digoxin is prescribed after an arrest of an attack of PNT with antiarrhythmic drugs for several days or weeks. More often, their use is shown in infants with a low initial blood pressure and a decrease in the contractility of the myocardium. In newborns, the dose of digoxin saturation is less - 0.01-0.03 mg / kg.

Strengthens the effect of antiarrhythmic treatment of children with potassium preparations in the form of a polarizing mixture, asparcam, then - nonsteroidal anabolics (potassium orotate, riboxin), as well as the use of sedative therapy, neurometabolic drugs (piracetam, aminalon, pyriditol, phenibut, etc.) vegetative vascular dystonia.

In the case of repeated and frequent attacks of PNT it is necessary to resort to electropulse therapy, as well as to surgical destruction of additional pathways in the myocardium.

Cardiac glycosides and verapamil (phinoptin, etc.) are contraindicated in WPW syndrome and other variants of premature ventricular contraction.

Nadzheludochkovye extrasystoles also differ from ventricular by the presence of a tooth R. Directed treatment requires extrasystoles that occur more often than 6-15 times per minute. Apply obzidan (0.1 mg / kg intravenously struino) or finaptin (0.1 mg / kg intravenously struino), potassium preparations, sedatives.

Ventricular extrasystoles are distinguished by the absence of the P wave and extended (> 0.12 s) QRS complexes. They can be monotopic; This includes allorhythmias (bigeminy, trigeminia), polyfocal and volley extrasystoles. Patients in need of emergency therapy with lidocaine (bolus injected 1-2 mg / kg, then drip - 2 mg / kg per hour). With tolerance to lidocaine, electropulse therapy is prescribed followed by the introduction of cordarone (2-3 mg / kg drip, then inside).

Ventricular paroxysmal tachycardia (HPV) is characterized by the appearance on the ECG of 3 or more broadened (> 0.12 s) deformed QRS complexes without the preceding or QRS-conjugated tooth P. Bi-directional and fusiform (pirouette) forms of HPT can be noted. The most effective lidocaine, may be used mexyl, rhythmylene, cordarone or novocainamide. In case of ineffectiveness, electropulse therapy is prescribed, since in the absence of rhythm conversion, arrhythmogenic collapse and pulmonary edema inevitably develop. Cardiac glycosides are not indicated in the treatment of FAT.

Atrial paroxysmal arrhythmia (MPA) is caused by trembling (the number of reductions is 220-350 per minute) or by flickering (> 350 per minute) of the atria and by an independent, rarer rhythm of the ventricles. According to the frequency of ventricular contractions, brady, normo- and tachyform of MPA are distinguished. Atrial flutter on the ECG, there is a separate correct rhythm of the P waves instead of the P teeth, reflecting the appearance of the pulse in the atrium, and the periodic occurrence of QRS-conjugated T (or not). The ventricular rhythm can be right and wrong. At fibrillation of the atria, there is a clinically observed "delirium of the heart" with a pulse deficit on the periphery. On the ECG there are no teeth P, duration RR is different.

In the opinion of MA Shkolnikova and co-workers. (1999), digoxin (especially with MPA tachyform) in combination with antiarrhythmic drugs of subgroup 1a (quinidine, novocaineamide, kinilentine, aymalin) or 1c (rhythm monm, flecainide) is used in the treatment of MPA. To monitor the frequency of the ventricular rhythm in chronic forms of atrial fibrillation, children use anaprilin, finaptin, amiodarone, sotalol. At bradyformah MPA is not strictly indicated the appointment of antiarrhythmic drugs and cardiac glycosides.

The use of membrane-stabilizing (cytochrome C, polarizing mixture - potassium, glucose), antioxidant (dimephosfon, Aevit, etc.) and neurometabolic (trental, coenzymes, cavinton, cinnarizine, nootropics, etc.) drugs that affect neurovegetative and metabolic mechanisms arrhythmias. Particularly effective dimephosphone (100 mg / kg per day) intravenously drip (duration of the course 10-14 days) in complex therapy of arrhythmia in children was noted by LA Balykova et al. (1999).

General principles of arrhythmia treatment:

• etiotropic treatment of arrhythmia in children, including psychotherapy, sedatives with neuroses, drugs that stabilize neurovegetative regulation, as well as treatment of diseases that caused organic damage (myocarditis, myocardial ischemia, rheumatism, intoxications, infections, etc.);
• basic treatment of arrhythmia in children, which means the restoration of electrolyte (primarily potassium-sodium) and energy balance (panangin, polarizing mixture, potassium orotate, etc.) in cardiomyocytes;
• drugs related to different groups of antiarrhythmic drugs.

1. blockers of sodium channels or membrane-depressants (subgroup 1a - quinidine, novocaineamide 1b - lidocaine, 1c - etatsizin, etc.);
2. beta-adrenoblockers, limiting the sympathetic effect on the heart (propranolol cordane, tracicor, etc.);
3. drugs that increase the repolarization phase and the duration of the action potential (cordapon, etc.);
4. blockers of slow calcium channels (veragtamil, diltiazem, etc.);
5. preparations of mixed action (rhythm monm, bonnecor, etc.).

Bradycardia is recorded at a heart rate of> 60 per minute. It can be in healthy adults and adolescents. At a pathology the bradycardia differs on a source of automatism:

1. Sinus: myogenic, neurogenic.
2. Replacement idiopathic or AV-rhythm.
3. Ventricular rhythm: sinoatrioventricular blockade 2: 1 (II degree), complete AV blockade (grade III).

With a sinus bradycardia, there is always a positive tooth of the QRS complex before the QRS complex. Neurogenic sinus bradycardia is observed in autonomic dysfunction, gastrointestinal diseases, meningitis and is accompanied by a distinct respiratory arrhythmia (inhalation reveals an increase in frequency, and exhalation of the pulse on exhalation). With myogenic bradycardia with myocardial damage, there is no connection with the respiratory cycle, respiratory arrest. In addition to inflammation of the myocardium (past or present), the cause of myogenic bradycardia can be the toxic effect of medications. With a pulse of less than 40 per minute, the probability of sinus bradycardia is low.

In the treatment of sinus bradycardia, atropine is usually used at a dose of 0.05-0.1 ml of 0.1% solution for 1 year of life (not more than 0.7 ml per injection) subcutaneously, intravenously; it is also possible to administer it inside (1 drop per 1 year of life). You can also use krasavki extract, bicarbon, besalol. Bellaspan and belloid should not be administered.

An alternate bradycardia, for example AV rhythm, may occur in the syndrome of weakness of the sinus node. CA-blockade 2: 1 on the ECG is represented by the rhythmic fallout of each 2nd complex of the NSA, while preserving the solitary tooth P through a strictly defined interval.

Complete AV-blockade is accompanied by two independent rhythms: more frequent rhythm of the atria (tooth P) and rare - of the ventricles. There are no regularities in the ratio of the teeth P and QRS.

Stable cardiac blockade, accompanied by attacks of Morgagni-Adams-Stokes (loss of consciousness, convulsions) and bradycardia of ventricular origin, serves as an indication for the use of an endocardial pacemaker. In the preoperative period, the required minute volume of the heart can be maintained by dobutamine, isadrin, sometimes adrenaline, and by using the transesophageal pacemaker. The same treatment regimen is also used in the syndrome of sinus node weakness accompanied by bradycardia.

The probability of antiarrhythmic effect in most antiarrhythmic drugs is 50% and only in a few clinical forms arrhythmia reaches 90-100%.

All antiarrhythmic treatment of arrhythmia in children is contraindicated in the stage III stage, SA-blockade and AB-blockade of II and III degree and syndrome of weakness of the sinus node. In these cases, cardiotonics, M-cholinolytics (atropine), rhythm drivers are used. In addition, antiarrhythmic drugs, which include glycosides, can themselves determine the arrhythmogenic effect, which often develops against hypokalemia and severe myocardial damage (inflammatory or toxic-metabolic genesis).