[Disorders of cardiac rhythm of ventricular origin in children]

The present study, based on the recent data in the literature and the authors' own experience, is a complex and up-to-date analysis of the three entities closely related, forming the "ventricular dysrhythmias": ventricular extrasystoles, ventricular paroxysmal tachycardia and ventricular fibrillation. For the ventricular extrasystoles--the most frequently met of these anomalies--the authors present the etiologic context (metabolic disturbances, drugs, myocardial lesions) and then analyze at length the ECG aspects (complex premature QRS, with modified morphology, enlarged, not preceded by P waves, etc.). The importance of studying the "coupling interval", usually fixed in the child, on the ECG tracing, is underlined. This shows, together with the monomorphous aspect of the extrasystolic QRS complexes, the presence of a single ectopic focus, and indicates a benign situation, making useless, in most of these cases, some specific treatment measures. The possible diagnosis errors (atrial or junction extrasystoles mainly with aberrant ventricular leads) are also discussed. After presenting the etiopathogenic data of the ventricular paroxysmal tachycardia the authors show that it is a rate rhythm disturbance in paediatrics (3% of the ectopic tachycardias), and may appear both on a normal heart (about 25% of the cases), and mainly in the presence of some preexisting cardiac lesions. The paper reports on the clinical aspects (partly, similar to those in the supraventricular paroxysmal tachycardia, but more severe) and especially on the aspects of electrocardiographic diagnosis. The necessity of differentiating it from other tachycardias with enlarged QRS complexes (mainly atrial and junction tachycardias with aberrant ventricular leads) is emphasized. The ventricular fibrillation, although rare in children (6% of the forms of terminal electrical activity), is the most severe disturbance of cardiac rhythm, making a clinical picture of "heart rest", that requires a maximum therapeutic emergency. The paper concludes with short references on a ventricular arrhythmia, very rarely met in children, the peak torsade, a clinical disease of syncopal type, electrocardiographically intermediary between paroxysmal tachycardia and ventricular fibrillation.