Prenatal diagnosis of a long QT syndrome by fetal magnetocardiography in an unshielded bedside environment

Abstract

Bedside fetal magnetocardiography revealed the exact diagnosis of the long QT syndrome in a period of the gestation when the fetus was electrically isolated by the vernix caseosa that hinders electrocardiography. To patients at risk of fetal cardiac abnormalities, magnetocardiography can be offered as a non-invasive diagnostic bedside procedure. The diagnosis should trigger closer surveillance and delivery in a perinatal center.

Magnetocardiography in Early Detection of Electromagnetic Abnormality in Ischemic Heart Disease

“…However, this problem does not arise with fetal magnetocardiography as we can monitor the fetal heart in a completely noninvasive fashion. In fact, a number of reports on the detection of the various fetal cardiac conditions, such as normal fetal cardiac development, 6) fetal bradyarrhythmias, 7) tachyarrhythmias, 8,9) Wolf-Parkinson-White syndrome, 10) long QT syndrome, 11) and cardiac hypertrophy 12) are reported. As described above, MCG is so sensitive to minor electromagnetic abnormalities of the heart, that the His bundle potential 13) and partial atrial standstill 14) may be detected using MCG mapping.…”

Fetal Presentation of Long QT Syndrome – Evaluation of Prenatal Risk Factors: A Systematic Review

“…Thus, fetuses with LQTS can exhibit bradycardia as a result of AVB, sinus bradycardia and tachyarrhythmias leading to a prenatal suspicion or diagnosis of LQTS. The antenatal diagnosis of a long QT interval was possible using fetal magnetocardiography [9,11,14,20] or fetal electrocardiography [17]. …”

“…In particular, attention should be paid to fetuses with a slightly reduced FHR of 110–120 bpm as well as fetuses with bradycardia <110 bpm, tachyarrhythmias or clinical signs of heart failure, such as pleural effusion and hydrops. As shown in cases 6, 9, 10 and 11 in table 1, some fetuses with LQTS exhibit a reduced heart rate variability [6,9,10,11]. Fetal magnetocardiography is able to detect the prolongation of the QT interval [9,11,14,20] as well as subtle changes in the short-term heart rate variability [41], thereby facilitating the prenatal diagnosis of LQTS [9,11,14,20].…”

“…The search terms ‘long QT syndrome’, ‘fetal arrhythmia’ and ‘congenital heart disease’ were used. The 30 reports were classified into three categories according to content: 20 reports [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21] describing 21 patients with LQTS documented abnormal cardiac findings found in utero (table 1); 5 reports [23,24,25,26,27] described series of LQTS patients and included prenatal cardiac findings for some of the fetuses (table 2), and 5 reports [28,29,30,31,32] described series of fetuses, some of whom were subsequently diagnosed as having LQTS, for whom echocardiography examinations had been performed because of abnormal cardiac findings detected incidentally during antenatal care (table 3). …”

“…LQTS accounts for more than 10% of the causes of sudden infant death syndrome [1]. Although several reports have described the prenatal cardiac findings of single or multiple cases of LQTS [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21], some patients with LQTS show only a slightly reduced baseline fetal heart rate (FHR) of 110–120 bpm in utero, as shown in figure 1. Since some fetuses with LQTS die in utero or during the neonatal period and because effective measures exist that are capable of preventing life-threatening episodes, such as syncope and ventricular tachycardia [1], antenatal diagnosis or a suspicion of LQTS may be helpful for improving the outcomes of fetuses with LQTS.…”