Home monitoring detects fetal supraventricular tachyarrhythmia recurrence during dose reduction of antiarrhythmic therapy
Year: 2020
Type: article
Study design: Observational Study
Abstract: Home fetal heart-rate monitoring (FHRM) using a home Doppler monitor has been shown to be useful in surveillance of fetal atrioventricular block in anti-Ro/SSA-positive pregnancies1. We applied this technique in a single-center study of fetuses with supraventricular tachyarrhythmia (SVA). Over a 12-year period, we evaluated 27 maternal–fetal pairs treated for sustained (> 70% of a 4-h monitoring period and/or hydrops) SVA. SVA types included atrial flutter (AF) (n = 4), atrioventricular re-entry tachycardia (AVRT) (n = 15, including three with AF), junctional ectopic tachycardia (JET) (n = 1), atrial ectopic tachycardia (n = 3) and permanent junctional reciprocating tachycardia (PJRT) (n = 4). Fetuses received transplacental treatment with digoxin (3/27), flecainide (5/27), sotalol (4/27) or combination therapy (15/27). Two hydropic fetuses with AVRT were treated with intramuscular and transplacental digoxin and transplacental sotalol. Once SVA converted to sinus rhythm (SR), the woman was discharged on the conversion dose of antiarrhythmic medication and instructed to carry out home FHRM three times a day, using a commercially available Doppler device. The women were asked to count the fetal heartbeat and describe the rhythm as regular or irregular; they sent a SMS audio text of the recording from their phone to their physician if the fetal heart rate was: (1) > 180 bpm or too fast to count; (2) < 100 bpm; or (3) irregular (Figure 1). If SVA recurred, the physician instructed the woman to take the usual dose of medication and monitor the fetal heart rate again after 2 h. If the fetus was still tachycardic after 2 h, the woman was seen in the clinic or the dosing regimen was changed. After 1–3 weeks of SR and resolution of hydrops, if present, the dose was reduced (Figure S1). The goal of dose reduction was monotherapy with the least proarrhythmic medication at the lowest dose. If SVA recurred during dose reduction, the dose was increased to the previous dose before a second attempt at reduction. Women were seen in the clinic for follow-up every 2–4 weeks. Characteristics of the SVA cohort are shown Table S1. Fetuses presented in SVA at a mean ± SD gestational age of 28.7 ± 5.7 weeks, and conversion to SR (25/27) occurred on average 1.3 ± 1.7 weeks later. Maintenance doses were decreased by a median of 33% to 50% (Table S2): digoxin by 50%, flecainide by 33% and sotalol by 33%. One fetus with JET and one with PJRT achieved rate control only; their doses were not reduced. Seven women detected SVA recurrence by home FHRM; all were confirmed by audio text message to the physician. Increasing the maintenance drug dose restored SR in 4/7 fetuses, which was confirmed by home FHRM, obviating the need for an outpatient visit. The increased dose was subsequently reduced, without recurrence of SVA 1–3 weeks later. SR could not be restored by dose escalation in 3/7 fetuses; they required a change in medication or addition of a new medication and hospital readmission for maternal monitoring. However, in these three cases, a subsequent change to monotherapy or a lower dose of two antiarrhythmic medications was possible. There were no false-positive episodes of SVA during home FHRM and no instances of undetected SVA during clinic visits during or after dose reduction. Infants in SR (n = 25) were delivered at a mean ± SD gestational age of 38.1 ± 1.3 weeks. SVA recurred after birth in 8/25 (32%) cases, of which 5/8 had AVRT. The fetus with rate-controlled PJRT was treated for 12 weeks with 360 mg/day of sotalol and was stillborn at 37 weeks. The fetus with rate-controlled JET was live born in JET at 37 weeks. Home FHRM, which is well accepted and successful in the surveillance of anti-Ro/SSA antibody-mediated atrioventricular block1, is also a reliable adjunct to fetal SVA management. Home FHRM can detect SVA recurrence in a timely manner, mitigating the risk of heart failure from undetected SVA. Furthermore, it can be used to reduce the antiarrhythmic drug dose, which may reduce the toxicity to the fetus from exposure for many weeks to antiarrhythmic medications associated with proarrhythmia2,3. It is well known that SVA recurrence may cease spontaneously. For example, over time, AVRT and PJRT become less likely to persist due to changes in the antegrade and retrograde conduction properties of accessory pathways associated with these types of SVA4. There is a possibility that success in maintaining SR following antiarrhythmic dose reduction is actually a manifestation of the natural history of spontaneous cessation of SVA. Implementation of home FHRM allows the antiarrhythmic dose to be reduced safely after conversion to SR in fetuses with SVA and may decrease the risk of proarrhythmia during maintenance antiarrhythmic therapy. 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DOI: 10.1002/uog.22172
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W3049366661