Review of diagnosis, treatment, and outcome of fetal atrial flutter compared with supraventricular tachycardia

Abstract

Objective: To review the diagnosis, treatment, and outcome of fetal atrial flutter compared with supraventricular tachycardia. Design: Retrospective review of published reports: 11 papers about fetal tachyarrhythmia published between 1991 and 2002 were selected for review. Main outcome measures: All selected studies were analysed for the type of arrhythmia, degree of atrioventricular block in atrial flutter, occurrence of hydrops fetalis, gestational age at diagnosis, first and second line drug treatment, associated cardiac and extracardiac malformations, and mortality of the fetuses. Results: Atrial flutter accounted for 26.2% of all cases of fetal tachyarrhythmias, and supraventricular tachycardia for 73.2%. Hydrops fetalis was reported in 38.6% and 40.5% of fetuses with atrial flutter and supraventricular tachycardia, respectively (NS). Hydropic fetuses with atrial flutter had higher ventricular rates (median 240 beats/min, range 240-300) than non-hydropic fetuses (220 beats/min, range 200-310) (p = 0.02), whereas the atrial rates were not significantly different (median 450 beats/min, range 370-500). Digoxin treatment resulted in a higher conversion rate in non-hydropic fetuses with fetal tachyarrhythmias than in hydropic fetuses (p < 0.001). The overall mortality of atrial flutter was similar to that of supraventricular tachycardia, at 8.0% v 8.9% (p = 0.7). Conclusions: The prevalence of hydrops fetalis did not differ in fetal atrial flutter and supraventricular tachycardia with 1:1 conduction. There was no difference between the response rate to digoxin in fetus with atrial flutter or supraventricular tachycardia. Mortality was similar in the two types of tachyarrhythmia.A ccording to published reports, atrial flutter accounts for a fifth to a third of all fetal tachyarrhythmias. 1 2 Fetal atrial flutter is defined as a rapid regular atrial rate of 300-600 beats/min accompanied by variable degrees of atrioventricular (AV) conduction block, resulting in slower ventricular rates. Previous data have suggested that fetal atrial flutter carries a worse prognosis than fetal supraventricular tachycardia (SVT) with 1:1 AV conduction, because of difficulties in controlling this rhythm disorder and the likelihood of associated congenital cardiac malformations.3 In contrast, Simpson and Sharland recently reported that the outcome of fetal tachyarrhythmias depends on the presence or absence of hydrops fetalis but not on the type of arrhythmia.2 Our aim in the present study was to review the diagnosis, treatment, and outcome of fetal atrial flutter compared with SVT. METHODS Study populationFor the review, data were collected from publications about fetal tachyarrhythmias published from 1990 onwards. Eleven papers about fetal tachyarrhythmia 1 2 4-12 were selected from the Medline database according to the following criteria:• only articles with more than 10 cases of fetal tachyarrhythmia were included • all publications had to contain data about consecutive cases of fetal tachyarrhythmia.• articles dealing with isola...

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