[Echocardiographic detection of fetal cardiac arrhythmias]

Using real-time directed M-mode and Doppler echocardiography we identified cardiac arrhythmias in 10 fetuses. One had signal tachycardia, one bradycardia, 5 supraventricular premature contractions, and 2 ventricular premature contractions (VPC), which were all self-limited. The diagnosis of VPC in one case was based on premature ending of foramen ovale flap's 2 nd wave on M-mode recording. All cases carried a favorable prognosis except the one with VPC who had a small ventricular septal defect overlooked prenatally. The 10 th case had II degrees atrioventricular block complicated by heart failure and died in utero. This study showed that most arrhythmias can be detected antenatally by analysing atrioventricular contraction sequences. It also proved that the characteristic M-mode pattern of foramen ovale flap is of value in evaluating the types of arrhythmias.