Prenatal nicotine exposure was associated with long-term impact on the cardiovascular system and regulation-Review.

AIM: The aim of this structured review was to discuss knowledge of nicotine use during pregnancy and long-term effects on children's cardiovascular function. METHODS: PubMed and MEDLINE were searched for original papers that covered various forms of nicotine exposure during pregnancy and this identified 314 papers published in English from inception of the databases to 1 March 2021. The research focus was prenatal exposure that had long-term effects on the cardiovascular system. The search was expanded from the reference list of the selected papers, which identified another 17 papers. RESULTS: The 34 original papers that were included covered 172,696 subjects from foetuses to 19 years of age. Cardiovascular autonomic dysfunction was discussed in 12 of the papers and 16 studies reported on blood pressure. The remaining studies covered structural or functional changes in arterial wall or heart. There were convincing data on autonomic dysfunction and increased blood pressure. Some data were conflicting and problems with misclassification of exposure were evident. CONCLUSION: Prenatal nicotine exposure was associated with long-term developmental changes in the cardiovascular system and regulation. There were no safe periods, doses or nicotine products during pregnancy and women should abstain when planning a pregnancy.

Snus users had high levels of nicotine, cotinine and 3-hydroxycotinine in their breastmilk, and the clearance was slower than in smoking mothers.

AIM: Using snus, an oral moist tobacco, has increased among pregnant women in Sweden, the only European Union country where sales are legal. This study evaluated whether snus generated similar concentrations of nicotine and its metabolites in breastmilk to cigarette smoking. METHODS: We analysed 49 breastmilk samples from 33 nursing mother - 13 snus users, six cigarette smokers and 14 controls - for concentrations of nicotine, cotinine and 3-hydroxycotinine. The mothers were recruited at antenatal clinics in Sweden from 2007 to 2012. RESULTS: The median nicotine concentration in breastmilk of the snus users was 38.7 ng/mL (0-137) versus 24.0 ng/mL (0-56) in smokers, with median cotinine levels of 327.6 ng/mL (37-958) versus 164.4 ng/mL and median 3-hydroxycotinine levels of 202.7 ng/mL (28-452) versus 112.4 (0-231), respectively. Nicotine was still detected in the breastmilk of eight of the 13 snus users after abstaining from tobacco for a median duration of 11 hours (0.6-12.5), while the breastmilk of the smokers was nicotine-free after four hours' abstinence. CONCLUSION: Snus users had high levels of nicotine and metabolites in their breastmilk and nicotine was found even after 12.5 hours of abstinence.

Prenatal Exposure to Snus Alters Heart Rate Variability in the Infant.

INTRODUCTION: Maternal use of smoked tobacco during pregnancy causes significant morbidity and mortality in the human infant including alterations in autonomic control with increased risk of sudden infant death syndrome. We hypothesized that maternal snus (smokeless tobacco) use during pregnancy affects autonomic cardiac regulation in the infant, as measured by heart rate variability (HRV) and the low frequency and high frequency ratio (LF/HF ratio). METHODS: A prospective observational study of 56 infants of women who used snus (n = 23) or cigarettes (n = 13) during pregnancy versus tobacco- and nicotine-free controls (n = 19). The nicotine dose was estimated by questionnaires at 4 timepoints pre- and post-natally. The infants' urine cotinine concentration and HRV during 2 hours of sleep were studied 1-2 months after birth. RESULTS: LF/HF ratio was higher in snus (mean 3.31; 95% CI 2.78-3.83) and smoke (3.51;2.54-4.47) compared to controls (2.15; 1.76-2.54, p = .002). Early prenatal nicotine exposure "without" any further exposure increased the LF/HF ratio (3.19; 2.55-3.84, p = .02). Continuous prenatal nicotine exposure "without" postnatal exposure was also associated with a residual increase in LF/HF ratio (4.40; 3.38-5.42, p < .001). There was no difference between infants exposed to smokeless versus smoked tobacco, suggesting a common constituent (nicotine) altering autonomic cardiac regulation. CONCLUSION: Infants to mothers who used snus during pregnancy showed lower vagal activity with an increased LF/HF ratio compared to controls, and similar to infants of smokers. Even early prenatal exposure to snus has a lasting impact on autonomic cardiac regulation suggesting a fetal "re-programing" of the developing autonomic nervous system. IMPLICATIONS: The results indicate that smokeless tobacco (Swedish snus) affects the developing autonomic nervous system during gestation. Even if exposure is interrupted during the first or second trimester, effects in autonomic cardiac regulation are seen in the 1-2 month-old infant. This underlines the importance of abstaining from all types of tobacco use during the whole pregnancy. Our findings may also have more general relevance to other routes by which nicotine can be delivered to a fetus and newborn.

Arterial Stiffness and Carotid Intima-Media Thickness in Children Exposed to Smokeless Tobacco in Fetal Life.

BACKGROUND: Arterial stiffening and increased intima-media thickness can be seen as early as childhood and are associated with increased risk of cardiovascular events in adult life. The authors hypothesized that exposure to prenatal smokeless tobacco (Swedish snus) without additional nicotine exposure after the breastfeeding period would be associated with increased arterial stiffness and intima-media thickening in preschool children. METHODS AND RESULTS: This was a longitudinal follow-up cohort study of children aged 5 to 6 years exposed to high doses of nicotine in utero. Women exclusively using snus and unexposed controls were enrolled in early pregnancy (gestational age range, 6-12 weeks). Exposure data were collected during and after pregnancy with questionnaires from both groups. For this study, only children of women using >48 mg nicotine per day during their entire pregnancy were included in the exposure group. Outcomes were determined in 40 healthy children (21 exposed to snus in utero). Ultrasonography of the common carotid artery was used to determine carotid intima-media thickness and calculate arterial stiffness index from the relationship between pulsatile changes in arterial diameter and arterial pressure. Children exposed to snus in fetal life had higher carotid stiffness (median 4.1 [interquartile range (IQR), 2.4-5] versus 2.9 [IQR, 2.1-3.5]; P=0.014) than tobacco-free controls. Carotid strain (relative diameter change) was lower in children exposed to snus (mean 16% [SD, 5.7%] versus 21% [SD, 6.6%]) than in controls (P=0.015). Carotid intima-media thickness did not differ significantly between children exposed to snus and controls. CONCLUSIONS: Exposure to snus during fetal life was associated with a stiffer carotid artery in preschool children.

Left atrial strain in neonates with congenital diaphragmatic hernia and length of stay in pediatric intensive care unit.

Introduction: The role of cardiac left ventricle (LV) dysfunction in children with congenital diaphragmatic hernia (CDH) has gained increasing attention. The hernia allows abdominal mass to enter thorax and subsequently both dislocating and compressing the heart. The pressure on vessels and myocardium alters blood flow and may interfere with normal development of the LV. A dysfunctional LV is concerning and impacts the complex pathophysiology of CDH. Hence, assessing both the systolic and diastolic LV function in the newborn with CDH is important, and it may add value for medical treatment and prognostic factors as length of stay (LOS) in pediatric intensive care unit (PICU). LV strain is considered an early marker of systolic dysfunction used in the pediatric population. Left atrial (LA) strain is an echocardiographic marker of LV diastolic dysfunction used in the adult population. When filling pressure of the LV increases, the strain of the atrial wall is decreased. We hypothesized that reduced LA strain and LV strain are correlated with the LOS in the PICU of newborns with CDH. Methods: This retrospective observational cohort study included data of 55 children born with CDH between 2018 and 2020 and treated at Karolinska University Hospital, Sweden. Overall, 46 parents provided consent. Echocardiograms were performed in 35 children <72 h after birth. The LA reservoir strain (LASr), LV global longitudinal strain, LV dimensions, and direction of blood flow through the patent foramen ovale (PFO) were retrospectively assessed using the echocardiograms. Results: Children with LASr <33% (n = 27) had longer stays in the PICU than children with LA strain ≥33% (n = 8) (mean: 20.8 vs. 8.6 days; p < 0.002). The LASr was correlated with the LOS in the PICU (correlation coefficient: -0.378; p = 0.025). The LV dimension was correlated with the LOS (correlation coefficient: -0.546; p = 0.01). However, LV strain was not correlated to LOS. Conclusion: Newborns with CDH and a lower LASr (<33%) had longer stays in the PICU than children with LASr ≥33%. LASr is a feasible echocardiographic marker of diastolic LV dysfunction in newborns with CDH and may indicate the severity of the condition.

Longitudinal ECG changes in tetralogy of Fallot and association with surgical repair.

Background: ECG abnormalities have been linked to adverse changes in right ventricular (RV) morphology and poor clinical outcomes in repaired Tetralogy of Fallot (rTOF). Our aim was to describe how ECG changes progress in early and intermediate follow-up and whether types of surgical strategy at the time of primary repair affected these changes. Methods: We studied patients with rTOF born 2000-2018 operated at our institution. Seven time points in relation to primary repair, follow-up, and pulmonary valve replacement (PVR) were identified. Patients correct with valve sparing repair (VSR), trans-annular patch (TAP) including with a monocusp valve (TAP + M) and with at least 3 ECGs were included. PQ interval, QRS duration, dispersion, and fragmentation, QTc duration and dispersion, JTc as well as presence of a right bundle branch block (RBBB) were analyzed. Medical records were reviewed for demographic and surgical data. Results: Two hundred nineteen patients with 882 ECGs were analyzed with a median follow-up time of 12.3 years (8.4, 17) with 41 (19%) needing PVR during the study period. QRS duration increased at time of primary repair to discharge from 66 msec (IQR 12) to 129 msec (IQR 27) (p < 0.0001) and at 1- and 6- year follow-up but showed only a modest and temporary decrease after PVR. QTc increased at the time of primary repair as well as prior to PVR. PQ interval showed a small increase at the time of primary repair, was at its highest prior to PVR and decreased with PVR. Type of surgical repair affected mainly QTc and JTc and was consistently longer in the TAP + M group until PVR. In VSR, QTc and JTc were prolonged initially compared to TAP but were similar after 1 year. After PVR, there were no differences in adverse ECG changes between surgical groups. Conclusions: PQ interval and QRS duration best correspond to the assumed volume load whereas the relationship with QTc and JTc is more complex, suggesting that these represent more complex remodeling of the myocardium. Before PVR, QTc and JTc are longer in the TAP + M group which may be due to a longer surgical incision.

Cardiovascular Health in Pregnant Women and Their Off-Spring.

Child development requires complex interactions between the pregnant woman and the growing child [...].

Hidden cardiovascular morbidity in children and young adults born with congenital diaphragmatic hernia: A population-based study.

INTRODUCTION: Congenital diaphragmatic (CDH) hernia is a rare congenital malformation with considerable mortality and morbidity in the neonatal period. The majority of the children today survive but little is known about long term cardiovascular morbidity. MATERIAL AND METHODS: This was a nationwide population-based prospective case-control study within a cohort of Swedish children with CDH, born 1982-2015. Five controls for each patient were randomly sampled from the population. The outcomes were the corresponding International Statistical Classification of Disease (ICD) codes for cardiovascular diagnoses according to ICD 9 and 10. RESULTS: There was an overrepresentation of cardiovascular diagnoses in the CDH group after one year of age compared to the control group, 8.0vs 0.5% (n = 53 versus n = 16). The risk of having a cardiovascular diagnosis in this CDH group was 15 times higher compared to the control group (HR 15.8, 95% CI: 9-27.6, p < 0.005). The diagnoses of cardiac arrhythmias and systemic hypertension were less common in the CDH group before the age of one year compared to the CDH group beyond the age of one year. Arrhythmia 3.7 vs 15.1%, systemic hypertension 3.7 vs 7.5%. CONCLUSION: CDH survivors have increased cardiovascular morbidity during childhood and young adulthood. This implies that structured follow up programs, covering cardiovascular morbidity, needs to be developed and should be offered in pediatric and adult care. Being born with CDH seems to be a risk factor for future cardiovascular diagnoses. LEVEL OF EVIDENCE: Level 3: Case-Control Study.

Blood Pressure and Heart Rate Variability in Preschool Children Exposed to Smokeless Tobacco in Fetal Life.

Background Maternal smoking during pregnancy has been associated with higher blood pressure and autonomic imbalance in the offspring. However, it has been difficult to determine the selective prenatal and postnatal contributions as children frequently have been exposed to smoking both before and after birth. The specific role of nicotine is also unclear. We aimed to determine whether exclusive prenatal exposure to nicotine from maternal use of smokeless tobacco (Swedish snus) in pregnancy was associated with blood pressure and autonomic heart rate control in their children. Methods and Results We measured oscillometric blood pressures in forty 5- to 6-year-old children with snus exposure in fetal life (n=21) and in tobacco-free controls (n=19). Taking the child's age and height into account, snus-exposed children had 4.2 (95% CI, 0.2-8.1) mm Hg higher systolic blood pressure than controls (P=0.038). The corresponding sex-, age-, and height-standardized systolic blood pressure centiles were 61 and 46 (95% CI of the difference, 2-28) (P=0.029). Heart rate variability was tested in 30 of the children. The spectral heart rate variability variable low-frequency/high-frequency ratio was higher (median, 0.69; interquartile range, 0.45-1.21) in snus-exposed children than in controls (median, 0.21; interquartile range, 0.32-0.57; P=0.034). Conclusions Prenatal snus exposure was associated with higher systolic blood pressure and altered heart rate variability at 6 years of age. These findings may indicate adverse prenatal programming of nicotine, but implications for cardiovascular health in later life remain to be studied. Meanwhile, women should be recommended to abstain from all types of tobacco and nicotine products during pregnancy.

[Fetal Cardiology. Experiences from a tertiary referral centre in Stockholm, Sweden]. / Fosterkardiologiska erfarenheter från Astrid Lindgrens barnsjukhus.

Fetal Cardiology. Experiences from a tertiary referral centre in Stockholm, Sweden This review provides a brief overview of the current position and clinical experiences of fetal cardiology at a tertiary referral centre in Stockholm, Sweden. In Stockholm, more than 60% of congenital cardiac defects requiring surgery or catheter intervention before one year of age are detected before birth. This not only results in termination of pregnancy in the majority of cases carrying a poor prognosis, but also conveys a better postnatal care and prognosis in cases of continued pregnancy. Almost all mechanisms generating fetal arrhythmias are elucidated using Doppler techniques, and arrhythmia treatment is preferably given in utero. Prenatal fetal echocardiography also provides the diagnostic tool necessary to detect and follow treatment of extracardiac conditions associated with fetal heart failure.