[Fetal supraventricular tachyarrhythmias. Experience of a fetal cardiology referral center]. / Taquiarritmias supraventriculares no feto. Experiência de uma unidade de referência em cardiologia fetal.

PURPOSE: To describe the presentation, diagnosis and treatment of fetal supraventricular tachyarrhythmias in a series of fetuses followed in a tertiary Fetal Cardiology Center. METHODS: Twenty-five fetuses with diagnosis of supraventricular tachyarrhytmia were reported from January 1989 to October 1997, among 3117 pregnant women referred for fetal cardiac evaluation. RESULTS: There were 17 fetuses with the diagnosis of supraventricular tachycardia (SVT) and 8 patients with atrial flutter (AF). Gestational age ranged from 26 to 40 weeks. Twelve patients were hydropic at presentation (6 with SVT and 6AF). Four fetuses with SVT showed structural abnormalities (two with Ebsten's anomaly and two with VSD). All patients were admitted to the Fetal Cardiology Unit for monitoring and treatment. Among 17 fetuses with SVT, twelve showed good response to digoxin administration, but this drug was not useful in any of the patients with flutter. In two patients with SVT and in six with AF, the pregnancy was interrupted to perform post-natal cardioversion. The mortality rate was 3/17 in the SVT group (including 2 patients with ebstein's anomaly and 0/8 in the flutter group) CONCLUSION: Fetal supraventricular tachyarrithmias are rare in the general population. Nevertheless, the fetus may present with severe heart failure and death. Considering the satisfactory therapeutic response, accurate diagnosis and early treatment of these conditions are extremely important.

Radiofrequency ablation of bundle branch reentrant tachycardia in a patient with atrial septal defect.

A 22-year-old woman with an atrial septal defect surgically corrected during childhood presented with a wide QRS complex tachycardia with left bundle branch block morphology. Electrophysiological study was performed and bundle branch reentrant tachycardia was induced with morphology identical to clinical tachycardia. Radiofrequency catheter ablation of the right bundle branch was successful, resulting in complete right bundle branch block and cure of her ventricular arrhythmia.