Fetal Electrophysiology

describe the serial heart rate variability assessment and electrophysiologic assessment of a twin pregnancy, during flecainide treatment of fetal supraventricular tachycardia in one twin. 1 This analysis of medication effects in the mother and both twins demonstrates a degree of thoroughness uncommon to many accounts of supraventricular tachycardia (SVT) management in the fetal literature.While on the surface this manuscript represents a well-written case report, its importance is much greater to cardiac electrophysiology as a whole.Van Leeuwen demonstrates the ability, using fetal magnetocardiography (fMCG)-a completely passive, safe, and noninvasive tool-to detect potentially life-threatening heart rate variability abnormalities and cardiac conduction changes in a presumably healthy twin fetus.The author further analyzes the drug's effect in the pregnant patient herself.Whether the changes manifest in the "unaffected" twin occurred solely as the result of flecainide exposure or were due to natural complications of the twin gestation itself is not the point.This report shows the potential that a form of intensive cardiac electrophysiologic diagnostics and care might be possible using fMCG and might favorably impact pregnancy outcome.This case also demonstrated what many of us who are involved in the prenatal electrophysiologic assessment of the developing human have long suspected-that fetal distress and perhaps demise itself might be the final common pathway resulting from diagnosable and potentially preventable cardiac electrophysiologic disease.Electrophysiologic alterations appear to elude commonly used obstetrical tests such as echocardiography and fetal monitoring.In a recent report by Zhao et al., nearly one-third of fetuses with congenital heart block were found to have unsuspected junctional or ventricular tachycardia by fMCG. 2 Van Leeuwen points out the high incidence of fetal demise in the older mother.Indeed, Reddy and colleagues report that in just the last 3 weeks of pregnancy, primiparous mothers over 40 stand almost a 1% chance of fetal loss.3 Multiple pregnancy is known to be a significant risk factor for fetal death even in the most advanced healthcare systems.In one study 4 of 355 twin and triplet pregnancies, at least one fetus died in the latter two trimesters of pregnancy in 13 (3.5%).For the monamniotic monochorionic twin pregnancy, this risk is substantially higher.Often premature delivery is implemented on the basis of very scant information regarding the fetal ischemic condition, such as reduced fetal heart rate