Fetal tachyarrhythmia with 1:1 atrioventricular conduction. Adenosine infusion in the umbilical vein as a diagnostic test.

This is the report of a case of fetal tachyarrhythmia with 1:1 atrioventricular conduction detected by pre-natal echocardiography in a fetus at 25-weeks gestation. Adenosine infusion via cordocentesis was performed as a diagnostic test to differentiate between atrioventricular nodal reentrant supraventricular tachyarrhythmia and atrial flutter. After infusion, transient 2:1 atrioventricular dissociation was obtained and the diagnosis of atrial flutter was made. Transplacental therapy with digoxin and amiodarone was then successfully used.

[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.

[Prenatal restriction of the foramen ovale]. / Restrição pré-natal do forame oval.

The parallel arrangement of the fetal intracardiac circulation requires unrestricted flow of blood through the foramen ovale in the atrial septum. Restriction to this flow is a significant cardiac abnormality, with potentially serious sequelae in post-natal life. A wide spectrum of abnormalities has been associated to the restriction of flow through the foramen ovale, including enlargement of right atrium, hypertrophy of right ventricle, enlargement of tricuspid valve annulus, hypoplastic syndrome of left heart, non-immune hydrops fetalis and supraventricular tachycardias. We report the diagnosis and follow-up of a fetus identified in the prenatal period, in whom the restriction of the foramen ovale originated severe tricuspid regurgitation and severe right ventricular hypocontractility, despite the morphologically normal tricuspid valve. After delivery, there was complete resolution of the clinical findings. The paramount importance of complete assessment of interatrial flow in high risk fetuses, allowing for the early detection and intervention, is emphasized.

[Intrauterine and perinatal management of complete atrioventricular block in the fetus]. / Manejo intra-uterino e perinatal do bloqueio atrioventricular total no feto.

PURPOSE: To report the experience of one of the most severe fetal rhythm disturbances, the complete atrioventricular block. METHODS: Descriptive study of 14 fetuses diagnosed and monitored at the Fetal Cardiology Unit, from January, 1991 to August, 1995. RESULTS: Fourteen cases of complete AV block were identified during the study period, with post-conceptional age between 22 and 38 weeks at the moment of diagnosis. Twelve cases were referred to the Fetal Cardiology Unit because of low heart rate during obstetric examination. Eight fetuses showed complete AV block without evidence of structural heart disease; maternal collagen tissue disease was diagnosed in three of these cases. Four neonates were discharged from the hospital, two of them with a permanent pacemaker, one with complete AV block but no pacemaker and the fourth with sinus rhythm. The remaining seven neonates presented with severe heart failure leading to death despite treatment. CONCLUSION: Complete AV block is a rare fetal condition, but carries a high morbidity and mortality. A several treatment techniques have been suggested to improve monitoring and survival of these patients, particularly in utero.