Prenatal diagnosis of junctional ectopic tachycardia

Fetal ventricular tachycardia: betablockers should be the first line treatment

Ventricular tachycardia (VT) is a rare cause of tachycardia during the fetal life. Coexistence of VT with sinus bradycardia or second-degree heart block strongly suggests long QT syndrome (LQTS) [1-3] and needs to administrate to the mother beta-blockers and in some cases magnesium sulfate [1,2,4]. When there is no argument for a LQTS several drugs have been proposed, most of them contraindicated in LQTS. We present a case of fetal LQTS with fetal VT and cardiac insufficiency with no antenatal clue for LQTS, successfully managed with propranolol. Thus, we suggest that in case of isolated fetal VT (i.e. without tumor or cardiomyopathy) beta blockers (excluding sotalol) should be the first line treatment since LQTS can be a possible cause for the dysrhythmia.

Fetal dysrhythmias

Fetal dysrhythmias are common abnormalities, usually manifesting as irregular rhythms. Although most irregularities are benign and caused by isolated atrial ectopics, in a few cases, rhythm irregularity may indicate partial atrioventricular block, which has different etiological and prognostic implications. We provide a flowchart for the initial management of irregular rhythm to help select cases requiring urgent specialist referral. Tachycardias and bradycardias are less frequent, can lead to hemodynamic compromise, and may require in utero therapy. Pharmacological treatment of tachycardia depends on the type (supraventricular tachycardia or atrial flutter) and presence of hydrops, with digoxin, flecainide, and sotalol being commonly used. An ongoing randomized trial may best inform about their efficacy. Bradycardia due to blocked bigeminy normally resolves spontaneously, but if it is due to established complete heart block, there is no effective treatment. Ongoing research suggests hydroxychloroquine may reduce the risk of autoimmune atrioventricular block. Sinus bradycardia (rate <3rd centile) may be a prenatal marker for long-QT syndrome.

Transplacental fetal therapy for junctional ectopic tachycardia

Junctional ectopic tachycardia (JET) is a rare type of tachyarrhythmia. A 39-year-old woman was transferred to our hospital for fetal tachyarrhythmia at 32 weeks' gestation. Fetal cardiac sonography revealed atrial and ventricular rates of 120-130 and 175-230 bpm, respectively, without 1:1 atrioventricular relationship. As ventricular tachycardia was considered to be the most probable diagnosis, transplacental therapy with digoxin and sotalol was done with partial response. Diagnosis of JET was made after birth. Although fetal JET is rare and prenatal diagnosis and treatment of this condition is still a challenge, differential diagnosis of fetal tachyarrhythmia should include this disorder.

Case report: an infant with congenital junctional ectopic tachycardia requiring extracorporeal mechanical oxygenation

PURPOSE OF REVIEW

A case report of an infant with hemodynamic compromise and impending collapse due to congenital junctional ectopic tachycardia. Medical therapy was maximized and he required the rapid initiation of extracorporeal life support, in order to achieve hemodynamic stability.

RECENT FINDINGS

This case report briefly reviews the presentation and treatment options for congenital junctional ectopic tachycardia, as well as the indications for initiation of mechanical support for this potentially lethal condition.

SUMMARY

Congenital junctional ectopic tachycardia is a rare though often fatal arrhythmia of the newborn or infant. Medical treatment options may be limited, or may require time to attain efficacy. Despite aggressive escalation of antiarrhythmic therapy, mechanical support in the form of extracorporeal mechanical oxygenation is a viable option, until the arrhythmia is well controlled and the myocardium recovers function.

A Case of Congenital Junctional Ectopic Tachycardia: Prenatal Diagnosis and Successful Radiofrequency Catheter Ablation in Infancy

It is difficult to make a definitive diagnosis of congenital junctional ectopic tachycardia (JET) in utero. We report a case in which congenial JET was suspected by fetal M-mode echocardiography. Fetal M-mode tracing of the atria and ventricle clearly showed a gradual acceleration of ventricular activity at the beginning of tachycardia, the warming-up sign of ectopic tachycardia, which was followed by simultaneous contractions of atrium and ventricle. This report also describes successful emergent radiofrequency catheter ablation of congenital JET in infancy with preservation of normal AV nodal conduction for this patient.

Persistent junctional reciprocating tachycardia in the fetus

BACKGROUND

Persistent junctional reciprocating tachycardia (PJRT) tends to be a persistent arrhythmia and requires aggressive therapeutic management. Diagnosis and management of this infrequently occurring tachycardia in the fetus at an early stage is of importance for the prevention of congestive heart failure (CHF).

METHODS

A retrospective study of four fetuses with supraventricular tachycardia (SVT) of the PJRT type was performed.

RESULTS

All had sustained SVT (mean of 228 beats/min) at a mean gestational age of 34 + 5 weeks, with CHF present in two. Three fetuses had prenatal characteristics of PJRT on M-mode echocardiography with a ventriculoatrial (VA)/atrioventricular ratio of > 1 on M-mode echocardiography suggesting a slow conducting accessory pathway. All four fetuses had postnatal confirmation of the diagnosis. Transplacental treatment with flecainide was effective in one patient; sotalol as a single drug or in combination with digoxin was partially effective in the remaining three. Two developed sinus rhythm, with short intermittent periods of tachycardia and decreasing signs of CHF; one case showed a minimal decrease in heart rate. Oral propranolol therapy converted two patients postnatally; in the remaining two patients radiofrequency ablation was performed at the age of 5 months and 6 years.

CONCLUSIONS

The characteristics of our prenatal PJRT cases included a sustained heart rate not exceeding 240 beats/min with a long VA interval, the presence of CHF and therapy resistance. Transplacental treatment should be initiated, possibly with a combination of sotalol and digoxin in non-hydropic cases, or flecainide, especially in case of fetal hydrops. Pharmacological therapy is to be preferred postnatally, but radiofrequency ablation seems to be indicated in therapy-resistant cases with CHF, even in the first months of life.