Which are the symptoms?
The symptoms of arrhythmias in children depends essentially on the underlying cardiac conditions, as well as on the age at presentation. Usually neonates and infants with fast supraventricular or ventricular arrhythmias present with congestive heart failure due to tachycardiomyopathy. This symptom may occur in permanent junctional reciprocating tachycardia, incessant atrial ectopic tachycardia, and ventricular tachycardia. Palpitations are generally the first clinical manifestation of tachyarrhythmias in older children, and require clinical investigation, generally with ECG and Holter recording. Syncope (loss of consciousness) may be due either to bradyarrhythmias or to ventricular tachyarrhythmias, and always requires a complete diagnostic work-up. Sudden death is uncommon in children, but when it occurs, it is generally caused by ventricular arrhythmias degenerating into ventricular fibrillation. In case of sudden death in children, a familial diagnostic work-up is generally recommended.
How is it diagnosed?
- Supraventricular arrhythmias
Supraventricular arrhythmias in children may occur either in the presence of a structurally normal heart or in the presence of congenital heart disease.
The incidence of atrioventricular reciprocating arrhythmias associated with WPW is 85% of arrhythmias during the fetal stage of life, and 82% of arrhythmias occurring during infancy. The incidence decreases to 65% in the 1-5 year-old age group, 56% in the 6-10 year-old age group, and 68% in children over 10 years of age. In most cases, tachycardias will resolve spontaneously by the end of infancy, but late recurrency may occur. Catheter ablation is frequently performed to treat tachyarrhythmias involving a single or multiple accessory pathway in highly symptomatic WPW children or in asymptomatic WPW children found at a high risk of sudden death.
Nodal reentrant tachycardia is uncommon during infancy, with an incidence of 23% in the 1-5 year-old age group, 34% in the 6-10 year-old age group, and 20% in those over 10 years of age. Most cases do not resolve spontaneously, requiring catheter ablation. Less common arrhythmias include atrial flutter and atrial ectopic tachycardia, with an incidence of about 10-15% during childhood, and most of them resolve spontaneously. If not, then persistent radiofrequency ablation is required to definitively cure them.
- Ventricular arrhythmias
Ventricular tachycardias are rare in childhood. Ventricular arrhythmias are diagnosed in children using EKG, chest X-Ray, echocardiograms, an electrophysiological study, or cardiac magnetic resonance. These arrhythmias are generally benign, normally disappear during exercise, and have a good long-term prognosis. Ventricular tachycardia occurring in children in association with hypertrophic cardiomyopathy, long QT syndrome (LQTS), Brugada syndrome (BrS), and arrhythmogenic right ventricular cardiomyopathy (ARVC) may have a worse prognosis, and must be studied with great care on a case-by-case basis.
Right ventricular outflow tract (RVOT) tachycardia is occasionally discovered in teenagers and, in these cases, ARVC must be excluded. The EKG shows left bundle branch block (LBBB) with a vertical or right axis. This form of ventricular tachycardia is commonly induced by exercise or emotions, can be reproducibly induced by isoprenalin, and is responsive to RF catheter ablation.
Idiopathic left ventricular tachycardia arising from the posterior fascicle of the left bundle branch is rare, and it responds to radiofrequency ablation. Catecholaminergic ventricular tachycardia is also induced by emotion, exercise, or isoprenaline and may degenerate into polymorphic ventricular tachycardia (torsade de pointes), frequently causing syncope if it terminates spontaneously, or cardiac arrest and sudden death if it degenerates into ventricular fibrillation. Torsade de point may also occur in children with long QT-syndrome, a familial disease characterized by prolonged and abnormal ventricular repolarization and risk of life-threatening ventricular arrhythmias, cardiac arrest, or sudden death. The mortality among untreated symptomatic children is up to 70% within 15 years after the first syncopal episode. Treatment includes beta-blockade, antiarrhythmic drugs, left cardiac ganglionectomy, and implantable cardiac defibrillator (ICD).
Complete atrioventricular block is the most important bradyarrhythmia in childhood. This arrhythmia may be congenital or may occur after cardiac surgery in congenital heart diseases. The symptom is usually syncope (loss of consciousness) due to the bradycardia, and the therapy generally is a pacemaker implant.
How is it treated?
Our center has specific experience with pediatric arrhythmias, and younger patients will be assisted by dedicated personnel throughout their clinical course, will be hospitalized with a parent, and will have dedicated leisure areas.