Clinical Characteristics of Focal Atrial Tachycardias Arising from the Atrial Appendages during Childhood

BACKGROUND: Focal atrial tachycardias (ATs) arising from the atrial appendages (AAT) are uncommon in adults. On the other hand, we frequently encounter AATs during childhood. However, the topographic distribution and clinical characteristics of focal ATs during childhood have not yet been clearly revealed. The aim of this study was to investigate the clinical characteristics of AATs in childhood. METHODS: The study population consisted of 16 consecutive pediatric patients with focal AT enrolled between March 1991 and June 2009. A retrospective analysis was performed. The patients with focal AT were divided into two groups: the AAT group and other AT (OAT) group, in which the foci arose from other atrial sites. RESULTS: Fifty percent had AAT. The AAT patients consisted of more males (88% vs 25%; P < 0.05), were more often asymptomatic at the initial visit (75% vs 25%; P < 0.05), and more often presented with an incessant form of the AT (88% vs 25%; P < 0.05) than the OAT patients. Second-degree atrioventricular block during slow ATs of <120 beats per minute were more often observed in the AAT patients (63% vs 13%; P < 0.05). The incidence of tachycardia-mediated cardiomyopathy was 19% out of all our subjects and 38% of the AAT patients. CONCLUSIONS: The AATs are the major source of focal ATs in pediatric patients that are typically incessant. These characteristics probably explain why a much higher percentage of the patients are presented with TMC.