The heart of a newborn infant undergoes 'programmed' postnatal transition

June 13, 2018, Medical University of Vienna

In the fetus, the blood vessel known as the ductus arteriosus, or ductus Botalli, bypasses blood from the lung artery to the aorta. A MedUni Vienna research group has now shown that this blood vessel remains open during the first few days of life to increase the pumping force of the left ventricle (which is less challenged before birth). This vessel then closes, having achieved its purpose.

Since lung respiration is not yet established in the unborn baby and oxygen is provided by the placenta, the pumps only a maximum of 20% of its oxygen-poor into the lung artery, the rest passes via the ductus Botalli into the descending aorta and to the lower body, approximately 30% of this blood is sent to the placenta via the umbilical arteries. The oxygen-rich blood from the placenta reaches the right atrium via the umbilical vein. Most of it flows via the open foramen ovale into the left atrium, the and finally into the ascending aorta and the vessels of the head and arms, thereby supplying both the coronary vessels and the baby's brain with oxygen.

With the onset of respiration after birth, the right pumps its oxygen-poor blood into the lung vessels. Oxygen exchange takes place in the inflated lungs, due to a reduction in lung pressure, the blood flow route in the ductus Botalli reverses and now goes from the aorta to the lung artery. These circulatory changes – the transition from prenatal to postnatal circulation – are part of a very complex process, which takes place in a programmed manner. The ductus arteriosus constricts and closes, usually only after the first few days of life.

Supportive effect in preterm infants clearly measurable

Since the lungs of a preterm infant are often immature, the described transition is often delayed and thus, the ductus Botalli may remain open longer. The immature left ventricle, which primarily pumped blood into the upper body before birth, now faces the challenge to pump its blood into the whole body. In preterm infants, in whom the ductus Botalli constricted as "programmed," an improvement in the pumping performance of the immature left ventricle could be demonstrated. The failure of the programmed closure of the ductus however led to a consistently lower pumping force.

This led the authors to conclude that the ductus arteriosus Botalli, by remaining open in the days following birth, "facilitates" the transition of the left ventricle. This occurs by the reversed blood flow route into the and thus, a greater cardiac "preload," which, via the so-called Frank Starling mechanism, results in an enhanced cardiac pumping force. In fact, the ductus arteriosus not only trains the left ventricle but also supports the circulation following birth. "The study conducted by Sigrid Baumgartner has shown us why the ductus Botalli remains open during the first days of life," explains lead investigator Ulrike Salzer-Muhar from the Division of Paediatric Cardiology of the Department of Pediatrics and Adolescent Medicine, "the programmed circulatory transition after birth is intended to ensure that we have a good start in life."

Use of functional echocardiography

The Department of Pediatrics and Adolescent Medicine of MedUni Vienna/Vienna General Hospital (Division of Neonatology, Intensive Care Medicine and Neuropediatrics) uses echocardiography to monitor cardiovascular function in premature babies. This cardiac ultrasound programme was set up by Ulrike Salzer-Muhar in 2009. This neonatology-cardiology working group recently used a pump model to analyse the pump function of the left ventricle in during their first four weeks of life.

Explore further: Researchers solve mystery behind baby's first breath

More information: Sigrid Baumgartner et al. Left ventricular pumping during the transition–adaptation sequence in preterm infants: impact of the patent ductus arteriosus, Pediatric Research (2018). DOI: 10.1038/pr.2018.22

Related Stories

Researchers solve mystery behind baby's first breath

March 5, 2013
(Medical Xpress)—Queen's University researchers have discovered how a key artery in a newborn baby's heart constricts and eventually closes when the baby takes its first breath and adjusts to the shock of being born. The ...

Benefit of early screening for vascular disorder among extremely preterm infants

June 23, 2015
Among extremely preterm infants, early screening for the vascular disorder patent ductus arteriosus before day 3 of life was associated with a lower risk of in-hospital death and pulmonary hemorrhage, but not with differences ...

No lasting benefit for early Tx of patent ductus arteriosus

December 16, 2015
(HealthDay)—Early treatment to induce closure of the patent ductus arteriosus (PDA) in preterm infants does not improve long-term outcomes, according to a clinical report published online Dec. 15 in Pediatrics.

D-transposition of the great arteries—a new era in cardiology

June 11, 2018
In the current issue of Cardiovascular Innovations and Applications , Angeline D. Opina and Wayne J. Franklin from the Baylor College of Medicine and Texas Children's Hospital, Houston, TX, USA consider the D-transposition ...

Congenital heart disease specialists develop nonsurgical technique to correct birth defects

July 29, 2014
A new technique for repairing the most common cardiac birth defect in newborns, commonly referred to as "a hole in the heart," has been used successfully to mend the condition in six premature infants without subjecting the ...

New nonsurgical repair of common heart defect in premature babies is shown to be effective

December 12, 2016
A new minimally invasive technique for repairing the most common cardiac birth defect in extremely premature newborns can be performed safely with a high success rate in babies as small as 755 grams - about 1.6 pounds - only ...

Recommended for you

Urgent call for prevention strategies for sleep-related infant deaths

June 22, 2018
Dr. Kyran Quinlan and colleagues at Rush issue an urgent call for prevention strategies for sleep-related infant deaths in his viewpoint, "Protecting Infants From Sleep-Related Deaths" published in the June 18 online issue ...

Infant colic leads to no ongoing problems, study shows

June 21, 2018
Colicky babies whose crying eases within three months have no ongoing behavioural problems according to new research by the Murdoch Children's Research Institute (MCRI).

Diagnosing and treating disorders of early sex development

June 19, 2018
Diagnosing, advising on and treating disorders of early sex development represent a huge medical challenge, both for those affected and for treating physicians. In contrast to the earlier view, DSD (Difference of Sex Development) ...

Use of alternative medicines has doubled among kids, especially teens

June 18, 2018
A new study published in JAMA Pediatrics shows that since 2003, the use of alternative medicines, such as herbal products and nutraceuticals, among children has doubled. The University of Illinois at Chicago researchers who ...

Virtual reality headsets significantly reduce children's fear of needles

June 18, 2018
The scenario is all too familiar for the majority of parents. The crying, the screaming and the tantrums as they try to coax their children into the doctor's office for routine immunizations. After all, who can't relate to ...

Both quantity and quality of sleep affect cardiovascular risk factors in adolescents

June 15, 2018
A study from a research team led by a MassGeneral Hospital for Children (MGHfC) physician finds that both the quantity and quality of sleep—the amount of time spent sleeping and the percentage of sleep that is undisturbed—in ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.