Fabrice Cuillier, MD*; P Lemaire, MD**; M. Deshayes, MD**; T. Attali, MD***, Alice Berta****.

*    Department of Gynecology, Félix Guyon' Hospital, 97400 Saint-Denis, Ile de la Réunion, France;
**   Echographist, Moufia"s street, Ile de la Réunion, France;
***  Department of Neonatology, Félix Guyon Hospital, 97400 Saint-Denis, Ile de la Réunion, France.

**** Student. Arizona State University. University Drive and Mill Avenue Tempe, Arizona 85281, USA.

Definition

Supraventricular tachycardia is a cardiac rythm disturbance characterized by sustained fetal heart rate between 220 and 260 bpm [1].

Case report

A 24-year-old G1P0, with an unremarkable medical history, presented to our unit at 22 weeks of pregnancy. Her family history was negative for cardiac diseases. She didn't take any medication or substances potentially influencing cardiac rhythm (caffeine). Her ultrasound scan at 13 weeks and triple test were normal.

At 22 weeks a supraventricular fetal tachycardia was observed by ultrasound with a heart rate of 240/min. The architecture of the heart was normal. The amount of amniotic fluid was normal. The fetus presented with anasarca, ascites, pericardial and pleural effusions.

Amniocentesis was not recommended. The patient was admitted to the hospital for the antiarrhythmic therapy. Flecaine was administered to the patient with the initial dose of 200 mg per day. Despite a therapeutic maternal serum Flecaine levels, the fetus didn"t convert to normal sinusal rhythm. We increased the Flecaine dosage to 300 mg per day and after six days the fetus converted to a normal cardiac rhythm. One week later the fetal ascites and hydrothorax disappeared. No adverse maternal side effects were noted during the three months of therapy. At 32 weeks, a fetal cerebral MRI was done and no signs of leukomalacia were found. Viral serology tests were negative.

The neonate was delivered at 38 weeks after induction of the labor (3000g). After twelve days of neonatal cardiac monitoring the baby was discharged in good condition. Three weeks after delivery the baby is doing well. 

Postnatally the diagnosis of Wolff-Parkinson-White syndrome was postulated.

Images 1, 2: 22 weeks of pregnancy; Transverse scans through the fetal thorax showing the four-chamber view of the heart and and pericardial effusion.

Images 3, 4:  22 weeks of pregnancy; Image 3 shows the M-mode examination of the heart with the fetal heart rate 231 bpm. Image 4 shows transverse scans of the fetal abdomen with ascites.

Images 5, 6:  22 weeks of pregnancy; Reverse flow at the level of the ductus venosus was present during fetal tachycardia.

 Videos 1, 2: 22 weeks: tachycardia and pericardial effusion.

Video 3: 24 weeks of pregnancy - transverse scan of the fetal thorax at the level of the four-chamber view. Resolution of the pericardial effusion and cardiac rhythm after the Flecaine administration is visible.

History

Supraventricular tachycardia was treated for the first time in 1980 by transplacental application of digitalis [2]. In 1988, successful prenatal application of Flecaïne acetate in the case of supraventricular tachycardia was first time reported by Wren and Hunter. Favorable results and outcome were published by Allan in 1991 [3]. In 1995, Wladimiroff et all reported that transplacental administration of the Flecaïne is associated with more rapid control of the arrhythmia and more frequent resolution of hydrops, compared with other drugs given by the transplacental route [3].

Pathogenesis

Supraventricular tachycardia can be a consequence of an automatic focus activity provoking the atrial contractions of higher rate than is the rate of sinoatrial node, or is a result of the re-entry mechanism, characterized by a circular electrical current running between the fast-conductive accessory pathways, ventricles, atrioventricular node and the atria in either direction. When the tachycardia is sustained, the diastole is shortened with decreasing atrial and ventricular filling time. This increases the systemic venous volume load and central venous pressure. Insufficient blood supply via the coronary arteries during diastole causes cardiac ischemia. The cardiac dilatation impairs contractility and the dilatation of the annulus fibrosus causes atrioventricular valve regurgitation. These factors result in the heart failure manifested by fetal hydrops.

Sonographic findings

Fetal tachycardia without other cardiac malformations can be observed during the second or the third trimester.

Implications for targeted examinations

Cardiac malformations must be eliminated by ultrasonography. Viral test are recommended.

Differential diagnosis

Ventricular tachycardia [2], fetus with long QT syndrome, isolated extrasystoles.

Associated anomalies

Supraventricular tachycardia can result in impairment of cerebral vessel autoregulation and may interfere with brain oxygenation, producing brain edema, injury of the periventricular vessels and irreversible brain damage with periventricular leukomalacia, multicystic encephalomalacia and intraventricular hemorrhage. But there is a paucity of data regarding the neurological damage caused by supraventricular tachycardia and heart failure [1].

Prognosis

Supraventricular tachycardia is associated with significant morbidity and mortality. It can result in the fetal hemodynamic compromise and non-immune hydrops or even fetal death. If the fetal tachyarrhythmia is associated with hydrops, the mortality ranges from 20 to 50%, making rapid diagnosis and therapy imperative. Neurological morbidity has been linked to fetal tachycardia and is probably the result of dysfunction of cerebrovascular autoregulation in hemodynamically compromised fetuses.

Jouannic et al (2003) described the perinatal data of 66 fetuses with supraventricular tachycardia. Junctional tachycardia was found in 50 fetuses, atrial flutter was found in 16 fetuses and 26 fetuses were affected by hydrops. After first line therapy, the supraventricular tachycardia persisted in 10 fetuses. Psychological development was normal for all the children (age five), without one.

Management

The optimal duration of treatment of prenatally diagnosed fetal supraventricular tachycardia remains undetermined. Postnatal recurrence of arrhythmia has been described in approximatively 50% of neonates. Some favor prophylactic continuation of the drugs during the first six to twelve month of life to prevent recurrence. According with Hansmann, in 10 to 20% of cases, supraventricular tachycardia will persist beyond the first year of life.
Treatment goals are cardioversion to sinus rhythm and reversal of cardiac dysfunction. Supraventricular tachycardia without hydrops is first treated pharmacologically in utero by giving digitalis to the mother. If digitalization does not achieve cardioversion, or if the fetal status continues to deteriorate, the drug should be withdrawn and alternative second-line drugs (such as quinidine, procainamide, verapamil and propanolol) are indicated. Flecaine has been described as highly effective medication even in hydropic fetuses, working efficiently, because it crosses the placenta rapidly, and reaching 80% of the maternal serum levels. Cessation of fetal supraventricular tachycardia after compression of umbilical cord has either been described by Pal et al [5].

References

1. Porat S., Anteby Y., Hamani Y., Yagel S. Fetal supraventricular tachycardia diagnosed and treated at 13 WG: a case report. Ultrasound Obstet Gynecol 2003; 31: 302-5.
2. Schleich J. M., Bernard du Haut Cilly F., Laurent M.C., Almange C. Early prenatal managment of fetal ventricular tachycardia treated in utero by amiodarone with long term follow-up. Prenat Diagn 2000; 20: 449-52.
3. Frohn-Mulder I. M., Stewart P. A., Witsenburg M., Den Hollander N.S.,
Wladimiroff J. W., Hess J. The efficacity of Flecaïne versus digoxin in the managment of fetal supraventricular tachycardia. Prenat Diagn 1995, 15: 1297-1302.
4. Oudjik M. A., Gooskens R. H. J. M., Stoutenbeek P., De Vries L.S., Visser G.H.A., Meijbooms E.J. Neurological outcome of childreen who were treated for fetal tachycardia complicated by hydrops. Ultrasound Obstet Gynecol 2004; 24: 154-8.
5. Pal A., Katona M. Cessation of fetal supraventricular tachycardia after compression of the umbilical cord. Ultrasound Obstet Gynecol 1997; 9: 204.
6. Fouron J.C. Fetal arrhythmias: The saint-Justine Hospital experience. Prenatal Diagnosis 2004; 24: 1068-80.