Amiodarone in Treatment of Fetal Supraventricular Tachycardia

Abstract

We report a case of nonimmune hydrops fetalis detected at 32 weeks of gestation. Fetal heart rate was 300 beats per minute. Ultrasound and fetal Doppler echocardiography showed it to be due to supraventricular tachycardia (SVT). Following failed maternal therapy with digoxin alone, amiodarone with digoxin was used. Conversion to sinus rhythm and resolution of hydrops followed this treatment. Since there is no ideal treatment protocol for these cases at present, we reviewed reports of transplacental treatment of SVT.

Maternal monitoring and safety considerations during antiarrhythmic treatment for fetal supraventricular tachycardia

“…Our initial search yielded 93 titles and abstracts, 19 full-text articles were retained for manual review 4,7,[13][14][15][17][18][19][20][21]38,[68][69][70][71][72][73][74][75] ( Figure 1). This represented a total of 495 cases of fetal SVT, 107 of which had hydrops fetalis.…”

“…Although some investigators specified that they performed investigations daily—including electrolytes, 17,18 ECG, 15,18,19 and drug levels 18 —most authors remained nonspecific about the frequency of testing during follow-up. 7,13,14,20,38,69,70,72–74 At a minimum, the signs and symptoms of toxicity, electrolyte abnormalities, and evidence of toxicity on ECG should be sought after initiation of treatment, at time of dose adjustment, or as indicated by clinical judgment. In the absence of resolution of the fetal SVT, doses should be increased or a new agent should replace/be added to the current treatment regimen.…”

Successful Digoxin Therapy of Fetal Supraventricular Tachycardia

“…However adverse effects of Amidrone are of concern (mainly neonatal hypothyroidism) and hence should be used as second line treatment. 6 Transplacental therapy should be the mode of therapy in nonhydropic fetuses and first choice in hydropic fetuses. However, when conversion to sinus rhythm is not achieved with several maternally administered antiarrhythmic drugs, one may also opt for direct fetal therapy.…”

Favorable neurodevelopmental outcome in a hypothyroid neonate following intracordal amiodarone for cardioversion of refractory supraventricular tachycardia in a fetus

“…Transplacental therapy consisting of antiarrhythmic medication (e.g., digoxin, flecainide, sotalol, and amiodarone) taken orally by the mother is usually effective in non-hydropic fetuses, with some studies reporting a cardioversion success rate of approximately 84% [1][2][3][4]. For fetuses with hydrops, transplacental therapy yields suboptimal cardioversion outcomes and is associated with a fetal and neonatal mortality as high as 30% [1,2,4].…”