Effect of QT interval-prolonging drugs taken in pregnancy on the neonatal QT interval

Introduction: Acquired QT interval prolongations due to drug side effects can result in detrimental arrhythmia. Maternal use of placenta-permeable drugs may lead to fetal exposure, thus leading to an increased risk of neonatal QT prolongation and arrhythmia. Objectives: This study aimed to evaluate the influence of maternal QT-prolonging medication on the neonatal QT interval. Methods: In the prospective KUNO-Kids health study, an ongoing population-based birth cohort, we classified maternal medications according to the known risk of QT interval prolongation. Effects on the neonatal QT interval were tested by linear regression analyses, correcting for perinatal confounders (birth weight, gestational age, birth mode, and age at ECG recording). Subgroup analyses were performed for selective serotonin reuptake inhibitors, proton pump inhibitors, and antihistamine dimenhydrinate. Logistic regression analysis was performed using a QTc of 450 ms as the cut-off value. Results: A total of 2,550 pregnant women received a total of 3,990 medications, of which 315 were known to increase the risk of QT prolongation, resulting in 105 (4.1%) neonates exposed in the last month of pregnancy. Overall, the mean age of the neonates at ECG was 1.9 days and the mean QTc (Bazett) was 414 ms. Univariate (regression coefficient -2.62, p = 0.288) and multivariate (regression coefficient -3.55, p = 0.146) regression analyses showed no significant effect of fetal medication exposure on the neonatal QT interval, neither in the overall nor in the subgroup analysis. Logistic regression analysis showed no association of exposure to maternal medication with an increased risk of neonatal QT interval prolongation (OR (odds ratio) 0.34, p = 0.14). Conclusion: The currently used maternal medication results in a relevant number of fetuses exposed to QT interval-prolonging drugs. In our cohort, exposure was found to have no effect on the neonatal QT interval.

Electrocardiographic Screening in the First Days of Life for Diagnosing Long QT Syndrome: Findings from a Birth Cohort Study in Germany

INTRODUCTION

Newborn sudden infant death syndrome (SIDS) has failed to decrease in the last decades, and a third of the neonatal cases occurred within the first 6 days of life. The long QT syndrome (LQTS) is a genetic disease with a prevalence of 1 in 2,000 live births and contributes to almost 10% of SIDS cases. Early identification of LQTS through electrocardiogram (ECG) screening is likely to reduce mortality.

METHODS AND RESULTS

In this ongoing prospective study we evaluated 2,251 ECGs from newborns participating in the KUNO Kids birth cohort study between July 2015 and July 2018. ECGs were recorded at a mean age of 2.0 days (IQR 0 days). The QT interval was corrected for heart rate using Bazett's formula (QTc). A QTc between 451 and 460, 461-470, and >470 ms was measured in 23 (1.0), 14 (0.6), and 62 (2.8%) participants, respectively. Fourteen neonates (0.62%) were admitted and monitored because their initial QTc was ≥500 ms. In 2 genetically analyzed participants, a mutation was found. One disease-causing for LQTS type 1 and the other of unclear significance. Cascade screening revealed affected members in both families.

CONCLUSION

A standardized neonatal ECG screening in the first days of life is able to identify neonates with a relevant transient form of prolonged QT intervals and to aid diagnosing congenital LQTS.