Fetal tachycardias: management and outcome of 127 consecutive cases

Abstract

Objective: To review the management and outcome of fetal tachycardia, and to determine the problems encountered with various treatment protocols.

Study design: Retrospective analysis.

Subjects: 127 consecutive fetuses with a tachycardia presenting between 1980 and 1996 to a single tertiary centre for fetal cardiology. The median gestational age at presentation was 32 weeks (range 18 to 42).

Results: 105 fetuses had a supraventricular tachycardia and 22 had atrial flutter. Overall, 52 fetuses were hydropic and 75 non-hydropic. Prenatal control of the tachycardia was achieved in 83% of treated non-hydropic fetuses compared with 66% of the treated hydropic fetuses. Digoxin monotherapy converted most (62%) of the treated non-hydropic fetuses, and 96% survived through the neonatal period. First line drug treatment for hydropic fetuses was more diverse, including digoxin (n = 5), digoxin plus verapamil (n = 14), and flecainide (n = 27). The response rates to these drugs were 20%, 57%, and 59%, respectively, confirming that digoxin monotherapy is a poor choice for the hydropic fetus. Response to flecainide was faster than to the other drugs. Direct fetal treatment was used in four fetuses, of whom two survived. Overall, 73% (n = 38) of the hydropic fetuses survived. Postnatally, 4% of the non-hydropic group had ECG evidence of pre-excitation, compared with 16% of the hydropic group; 57% of non-hydropic fetuses were treated with long term anti-arrhythmics compared with 79% of hydropic fetuses.

Conclusions: Non-hydropic fetuses with tachycardias have a very good prognosis with transplacental treatment. Most arrhythmias associated with fetal hydrops can be controlled with transplacental treatment, but the mortality in this group is 27%. At present, there is no ideal treatment protocol for these fetuses and a large prospective multicentre trial is required to optimise treatment of both hydropic and non-hydropic fetuses.

Figure 1

Characteristics of 127 fetuses with tachycardias. AF, atrial fibrillation; SVT, supraventricular tachycardia.

Figure 2

Treatment and outcome of non-hydropic fetuses with tachycardias. AF, atrial fibrillation; SVT, supraventricular tachycardia; TVD, tricuspid valve dysplasia; NND, neonatal death; IUD, intrauterine death.

Figure 3

Treatment of hydropic fetuses with tachycardias. AF, atrial fibrillation; IUD, intrauterine death; NND, neonatal death; SID, sudden infant death; SVT, supraventricular tachycardia; TOF, tracheo-oesophageal fistula; TOP, termination of pregnancy.