Ventricular Tachyarrhythmias (VT) in Children

Introduction to Ventricular Tachyarrhythmias in Children

Ventricular tachyarrhythmias are abnormal heart rhythms originating from the ventricles that can be life-threatening in children. These arrhythmias are characterized by a rapid heart rate (typically >120 beats per minute) and can lead to hemodynamic instability if left untreated. While less common than supraventricular tachycardias in the pediatric population, ventricular tachyarrhythmias require prompt recognition and management due to their potential for sudden cardiac death.

The incidence of ventricular tachyarrhythmias in children is estimated to be 1-2 per 100,000 per year, with a higher prevalence in those with underlying structural heart disease or channelopathies. Understanding the etiology, classification, clinical presentation, and management strategies is crucial for healthcare providers dealing with pediatric patients.



Objective QnA: Ventricular Tachyarrhythmias in Children
  1. Question: What is the definition of ventricular tachycardia (VT) in children? Answer: Ventricular tachycardia in children is defined as three or more consecutive ventricular beats at a rate > 120 beats per minute.
  2. Question: Which congenital heart disease is most commonly associated with ventricular tachycardia in children? Answer: Tetralogy of Fallot repair is most commonly associated with ventricular tachycardia in children with congenital heart disease.
  3. Question: What is the most common cause of polymorphic VT in children with structurally normal hearts? Answer: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is the most common cause of polymorphic VT in children with structurally normal hearts.
  4. Question: Which inherited channelopathy is associated with bidirectional VT? Answer: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is associated with bidirectional VT, typically induced by exercise or emotional stress.
  5. Question: What is the typical ECG appearance of torsades de pointes? Answer: Torsades de pointes appears as a polymorphic VT with characteristic twisting of the QRS complexes around the isoelectric line.
  6. Question: Which medication is first-line therapy for hemodynamically stable VT in children? Answer: Amiodarone is often considered first-line therapy for hemodynamically stable VT in children due to its efficacy and relatively low risk of pro-arrhythmia.
  7. Question: What is the immediate management for pulseless VT in children? Answer: Immediate defibrillation with 2 J/kg is the first step in managing pulseless VT in children, followed by CPR if unsuccessful.
  8. Question: Which imaging modality is preferred for identifying structural abnormalities associated with VT in children? Answer: Cardiac MRI is the preferred imaging modality for identifying structural abnormalities associated with VT in children, such as fibrosis or infiltrative diseases.
  9. Question: What is the role of beta-blockers in managing ventricular arrhythmias in children? Answer: Beta-blockers are first-line therapy for many ventricular arrhythmias in children, particularly those associated with long QT syndrome, CPVT, and some forms of idiopathic VT.
  10. Question: Which electrolyte abnormality can precipitate ventricular arrhythmias in children? Answer: Hypokalemia can precipitate ventricular arrhythmias in children, particularly in those with underlying channelopathies or on medications that prolong the QT interval.
  11. Question: What is the most common site of origin for idiopathic VT in children? Answer: The right ventricular outflow tract is the most common site of origin for idiopathic VT in children.
  12. Question: Which genetic syndrome is associated with an increased risk of ventricular arrhythmias and sudden cardiac death in children? Answer: Marfan syndrome is associated with an increased risk of ventricular arrhythmias and sudden cardiac death in children, particularly in those with significant aortic root dilation.
  13. Question: What is the role of implantable cardioverter-defibrillators (ICDs) in managing ventricular arrhythmias in children? Answer: ICDs are used for primary or secondary prevention of sudden cardiac death in children at high risk of life-threatening ventricular arrhythmias, such as those with certain channelopathies or cardiomyopathies.
  14. Question: Which antiarrhythmic medication is contraindicated in children with Brugada syndrome? Answer: Class IC antiarrhythmic drugs (e.g., flecainide, propafenone) are contraindicated in children with Brugada syndrome as they can unmask or exacerbate the ECG pattern and increase arrhythmia risk.
  15. Question: What is the significance of epsilon waves on ECG in children with ventricular arrhythmias? Answer: Epsilon waves are characteristic of arrhythmogenic right ventricular cardiomyopathy (ARVC) and represent delayed activation of the right ventricle due to fibrofatty replacement of myocardium.
  16. Question: Which non-invasive test is useful in risk-stratifying children with hypertrophic cardiomyopathy for ventricular arrhythmias? Answer: Ambulatory ECG monitoring (Holter) is useful in risk-stratifying children with hypertrophic cardiomyopathy, as the presence of non-sustained VT is a risk factor for sudden cardiac death.
  17. Question: What is the role of catheter ablation in managing ventricular arrhythmias in children? Answer: Catheter ablation can be curative for some forms of idiopathic VT in children and may be used as an adjunct therapy in those with recurrent VT despite medical management.
  18. Question: Which medication is used as an adjunct to beta-blockers in children with CPVT who continue to have arrhythmias? Answer: Flecainide is often used as an adjunct to beta-blockers in children with CPVT who continue to have arrhythmias despite maximal beta-blocker therapy.
  19. Question: What is the typical ECG appearance of accelerated idioventricular rhythm (AIVR)? Answer: AIVR typically presents as a wide complex rhythm with a rate slightly faster than the underlying sinus rate (usually 60-120 bpm) and often shows fusion or capture beats.
  20. Question: Which cardiomyopathy is associated with an increased risk of ventricular arrhythmias in children who are competitive athletes? Answer: Hypertrophic cardiomyopathy is associated with an increased risk of ventricular arrhythmias in children who are competitive athletes, particularly during intense physical exertion.
  21. Question: What is the role of left cardiac sympathetic denervation in managing ventricular arrhythmias in children? Answer: Left cardiac sympathetic denervation can be used as an adjunct therapy in children with refractory ventricular arrhythmias, particularly in those with long QT syndrome or catecholaminergic polymorphic ventricular tachycardia.
  22. Question: Which metabolic disorder can present with life-threatening ventricular arrhythmias in infants? Answer: Certain fatty acid oxidation disorders, such as very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency, can present with life-threatening ventricular arrhythmias in infants, particularly during fasting or illness.
  23. Question: What is the significance of T wave alternans in children with ventricular arrhythmias? Answer: T wave alternans is a marker of electrical instability and may indicate an increased risk of life-threatening ventricular arrhythmias, particularly in children with long QT syndrome or cardiomyopathies.
  24. Question: Which antiarrhythmic medication is preferred for treating ventricular arrhythmias in children with significant left ventricular dysfunction? Answer: Amiodarone is often preferred for treating ventricular arrhythmias in children with significant left ventricular dysfunction due to its minimal negative inotropic effect compared to other antiarrhythmic drugs.
  25. Question: What is the role of mexiletine in managing ventricular arrhythmias in children? Answer: Mexiletine, a Class IB antiarrhythmic, can be used as an adjunct therapy in children with long QT syndrome type 3 and can also be effective in some cases of idiopathic ventricular tachycardia.
  26. Question: Which imaging finding on cardiac MRI is suggestive of arrhythmogenic right ventricular cardiomyopathy (ARVC) in children? Answer: Late gadolinium enhancement in the right ventricular free wall or localized right ventricular aneurysms on cardiac MRI are suggestive of ARVC in children.
  27. Question: What is the significance of a short-coupled variant of torsades de pointes in children? Answer: Short-coupled variant of torsades de pointes is a rare but malignant form of polymorphic VT that can occur in children with structurally normal hearts and is characterized by a very short coupling interval of the initiating premature ventricular complex.
  28. Question: Which surgical procedure can be considered for children with recurrent ventricular tachycardia originating from a discrete myocardial scar? Answer: Surgical ventricular tachycardia ablation or aneurysmectomy can be considered for children with recurrent ventricular tachycardia originating from a discrete myocardial scar, particularly when catheter ablation has failed or is not feasible.


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