Cardiac arrhythmias in children

Main causes of development

The etiology of pediatric arrhythmias differs fundamentally from pathology in adult patients. The leading role here is played not by organic myocardial changes, but by functional failures against the background of immaturity of regulatory systems.

All factors are usually divided into two large groups:

• Extracardiac causes. Most common. Arrhythmia is triggered by a disruption of neurohumoral regulation in an intact heart. Triggers include perinatal nervous system lesions (hypoxia, prematurity), endocrine disorders, psychautonomic overloads, dysmetabolic states (magnesium and selenium deficiency), and acute infections.
• Cardiac (organic) causes. Associated with anatomical damage to the heart itself. These include congenital heart defects (CHD), carditis, acute rheumatic fever, cardiomyopathies, and minor developmental anomalies. Defects form from the 2nd to the 8th week of embryogenesis.

A combined mechanism is often encountered, where the organic substrate is exacerbated by extracardiac autonomic shifts.

How arrhythmias manifest at different ages

The specifics of the clinical presentation directly depend on the child's age and ability to articulate complaints. About 40% of cases have no external manifestations at all and are discovered incidentally after an acute respiratory viral infection (ARVI) or during a routine ECG.

Neonates and infants Symptoms are maximally nonspecific. The infant cannot voice discomfort, so signs of hypoxia and autonomic failure come to the foreground:

• weak suckling and poor weight gain;
• motiveless anxiety or, conversely, severe lethargy;
• transient cyanosis of the nasolabial triangle, pallor;
• dyspnea, tachycardia, and excessive sweating.

Older children and adolescents Unlike adults, children rarely complain about classic "fluttering" or skipped heartbeats. During puberty, symptoms acquire an emotional coloring. Patients report cardialgia, insomnia, weather sensitivity. If the arrhythmia is hemodynamically significant (sinus bradycardia, pronounced AV blocks, paroxysmal tachycardia), cerebral perfusion is impaired, leading to dizziness and syncopal states.

Diagnostic algorithm

Due to the close connection of arrhythmias with comorbid conditions (hypertensive-hydrocephalic syndrome, connective tissue dysplasia), diagnostics are always multidisciplinary, involving a neurologist, endocrinologist, and ENT specialist.

1. Physical examination. Thorough pulse palpation (detecting tachy-, bradycardia, skipped pulse waves) and auscultation to rule out organic murmurs.
2. Standard ECG. Basic screening. Sinus arrhythmia and incomplete right bundle branch block may be normally detected in children.
3. Holter monitoring (Holter ECG). Indispensable for finding hidden disorders and assessing their connection with periods of sleep or wakefulness.
4. Functional tests. Treadmill test or cycle ergometry helps differentiate functional extrasystoles (they disappear during exertion) from organic ones.
5. Assessment of autonomic status. Cardiointervalography confirms the typical pattern—vagotonia against the background of weak sympathetic influences.

In complex cases, invasive ECG mapping and transesophageal ECG are used in specialized departments.

Prognosis and basic treatment principles

The prognostic significance of an arrhythmia depends on the presence of an organic substrate and its impact on hemodynamics.

Favorable course is typical for functional shifts (isolated sinus tachycardias, rare monotopic extrasystoles). They are asymptomatic and rarely require aggressive intervention. Unfavorable prognosis is associated with persistent forms (ventricular tachycardias, long Q-T interval syndrome, AV blocks) that reduce cardiac output.

Treatment is based on three pillars: relief of emergency life-threatening conditions, preventive support against recurrences, and etiopathogenetic therapy. Basic therapy for 2–3 months is mandatory to improve myocardial trophism and normalize the tone of the autonomic nervous system.

Class and exam questions

What else to study on this topic

• Classification of arrhythmias by impulse formation mechanism
• Hemodynamic consequences of paroxysmal tachycardias in children
• Features of congenital heart defects (CHD) and their impact on rhythm
• The role of 24-hour ECG monitoring (Holter) in pediatrics
• Sick sinus syndrome (SSS) in childhood

Other topics in "Chapter 6. Diseases of the Cardiovascular System"

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