Summary
Ventricular tachycardia is an arrhythmia which is faster than sinus rhythm and which originates in the ventricles. By definition, it is present when three or more consecutive beats are observed, but as a clinically significant arrhythmia it is usually sustained. It is rare in infancy and incidence is estimated at 1 in 50,000 - 1in 100,000 live births. Pediatricians are reluctant to establish the diagnosis of ventricular tachycardia in infancy and most cases are initially mistaken for 'supraventricular'' tachycardia. If the QRS complex in a sustained tachycardia is abnormal, the diagnosis of ventricular tachycardia should be considered more likely. Several types of ventricular tachycardia are encountered in infancy but the main significant arrhythmia is incessant infant ventricular tachycardia which presents between the age of three months and two years, usually with heart failure. Reported ventricular rates range from 167 - 440 with a mean of 260 per minute and the QRS most often shows a right bundle branch block/superior axis morphology indicating a posterior left ventricular origin for the tachycardia. The underlying problem in most cases is probably a tiny myocardial hamartoma, which is usually beyond the resolution of imaging techniques. Before the introduction of more effective and newer antiarrhythmic drugs, surgical ablation was often required. The most effective drugs in current clinical use include amiodarone and flecainide. This arrhythmia will usually resolve by the age of five years and drug treatment can be withdrawn without recurrence. Other ventricular tachycardias in infancy are rare and require specialist evaluation.
Expert reviewer(s)
Last update: April 2003
