[Remote catamnesis of paroxysmal supraventricular arrhythmias which debuted in childhood].

This article deals with the 23-years assessment of natural history of 57 patients with paroxysmal supraventricular tachycardia debuted in childhood. Variants of clinical course of disease are described: cardiac, syncopal, abdominal, asymptomatic. In absence of treatment majority of paroxysmal tachycardias were characterized by wavy change of their clinical manifestations with periods of pronouncedly increased and decreased activity lasting from 3 to 5 years. Time interval between attacks was important for prognosis. Severity of disease was determined by relationship of three factors: frequency, duration of attacks and ability of a tachycardia to cause disturbances of central hemodynamics. Tachycardia with asynchronous AB conduction and heart rate above 250/min in one year old and above 220/min in older children was associated with increased risk of development of acute heart failure during an attack. Risk of heart failure was not related directly to frequency of attacks but arose when duration of tachycardia with critical heart rate exceeded 8 hours.