Tag Archive for: congenital heart defect

Paper cutout of head with brainwaves

Lifesaving ICDs can cause anxiety, stress, PTSD for parents and kids

Paper cutout of head with brainwaves

Research shows that children with implantable cardioverter-defibrillators, and their parents, are at risk for anxiety, post-traumatic stress disorder and other psychological distress.

Recent advances in design and efficiency of implantable cardioverter-defibrillators (ICDs) have led to their increased use in younger patients, protecting more children with congenital heart disease from sudden cardiac arrest and sudden cardiac death, says a commentary in the journal Heart Rhythm. However, living longer with these devices and the day-to-day worry that they may have to deliver a lifesaving shock in the blink of an eye, may cause unusually high rates of anxiety, stress and other psychosocial distress for children with ICDs and their families.

Commentary authors Vicki Freedenberg, Ph.D., RN, electrophysiology nurse scientist, and Charles Berul, M.D., chief of cardiology, both from Children’s National Hospital, note that current available research shows both children with these ICDs and their parents are at risk for anxiety, post-traumatic stress disorder (PTSD) and other psychological distress. They highlight a new study published in the same journal that reports data related to prevalence and factors associated with PTSD in children with ICDs and their parents as a good start to better understanding these impacts.

Why it matters

Freedenberg and Berul say that the new study adds important information to an area without a lot of previous research. They also point out that understanding the long-term impacts of life with these devices is critical to ensuring the overall long-term health and wellbeing of both the children with these devices and their families.

What’s been the hold-up in the field?

The development of devices that work for younger children with congenital heart disease, including advances in ICDs and pacemakers, has increased in the last decade. In this time, studies of how these devices work for children have focused predominantly on clinical outcomes and questions related to clinical care.

As survival rates for children have increased, research needs to shift from the study of mortality and clinical outcomes toward understanding the full spectrum of how these devices impact daily life for these children and their families.

Moving the field forward

According to Freedenberg and Berul, the new study importantly includes both patient and parent perspectives, which is a first in this research area. They also offer recommendations for future studies, including the use of comparison groups to allow for generalization of findings. Researchers might also ask research questions to determine whether the device itself or the medical and non-medical factors that often occur simultaneously are more important to predicting mental health and wellbeing.

However, the commentary concludes with the most important takeaway: More research, with specific parameters focused on the impact of clinical interventions, is desperately needed to truly understand all the ways that children and their families are affected throughout life by the clinical care and support they receive.

Read the full commentary, Potential for shock leads to potential for stress, in the journal Heart Rhythm.

Baby on ventilator

JAMA study shows no benefit to nitric oxide in cardiopulmonary bypass for young children

Baby on ventilator

An international clinical trial showed that nitric oxide doesn’t help kids recover faster from cardiac surgery with cardiopulmonary bypass.

A study published in JAMA finds that the practice of introducing nitric oxide into the gas flow of the cardiopulmonary bypass oxygenator does not improve recovery or reduce the amount of time a child under age 2 needs to be on a ventilator after cardiac surgery.

Children’s National Cardiac Surgery Chief Yves d’Udekem, M.D., Ph.D., co-authored the international study, which is already leading to changes in how hospitals around the world care for children with congenital heart disease (CHD).

The results are from a double-blind, randomized controlled trial with more than 1,200 participants across six centers in Australia, New Zealand and the Netherlands. The research team found that children under age 2 who had cardiac surgery with cardiopulmonary bypass spent about the same number of days on ventilators after surgery, whether nitric oxide was used during surgery or not.

“These findings do not support the use of nitric oxide delivered into the cardiopulmonary bypass oxygenator during heart surgery,” the authors conclude.

What this means

Previous smaller, single center studies had shown early indications that nitric oxide delivered during heart surgery could possibly improve recovery and shorten the need for respiratory support after surgery by reducing the occurrence of low cardiac output syndrome in children under age 2.

This large-scale international trial showed that this is not the case.

Why it matters

Based on these earlier studies, many hospitals in the United States and around the world who perform critical heart surgery on young children with congenital heart disease had already started to incorporate nitric oxide into cardiopulmonary bypass. This new, more robust data is helping hospitals reassess this practice. Many are stopping it altogether based on the findings.

This work is an important reminder of how valuable well-designed, large-scale, double-blind, randomized, controlled trials are to defining, improving and refining best practices in clinical care.

Also, trials of this size and significance in pediatrics generally, and CHD specifically, take a very long time to complete, if they are ever able to be completed at all. That’s because the number of children with these conditions is relatively small and spread out, even though CHD is the most common birth defect in the world. The authors say it is a major accomplishment to have completed a trial of this size and  in such a short time. Even better, the data gathered from this sample of patients from across international borders can be used to provide even more insights into how best to care for these children as they continue to grow and develop.

caspase molecule

Caspases may link brain cell degeneration and cardiac surgery

caspase molecule

The review summarizes both the known physiological roles of caspases as well as some of the well-characterized neurotoxic effects of anesthetics in pre-clinical models.

A review article in the journal Cell Press: Trends in Neuroscience outlines the wide variety of cellular signaling roles for caspase proteins — a type of cellular enzyme best known for its documented role in the natural process of cell death (apoptosis). The authors, including Nemanja Saric, Ph.D., Kazue Hashimoto-Torii, Ph.D., and Nobuyuki Ishibashi, M.D., all from Children’s National Research Institute, pay particular attention to what the scientific literature shows about caspases’ non-apoptotic roles in the neurons specifically. They also highlight research showing how, when activated during a cardiac surgery with anesthesia and cardiopulmonary bypass, these enzymes may contribute to the degeneration of brain cells seen in young children who undergo heart surgery for critical congenital heart defects (CHDs).

Why it matters

The review summarizes both the known physiological roles of caspases as well as some of the well-characterized neurotoxic effects of anesthetics in pre-clinical models.

The authors propose that these non-apoptotic activities of caspases may be behind some of the adverse effects on the developing brain related to cardiac surgery and anesthesia. Those adverse effects are known to increase risk of behavioral impairments in children with congenital heart disease who underwent cardiac surgery with both anesthesia and cardiopulmonary bypass at a very young age.

This work is the first to propose a possible link between developmental anesthesia neurotoxicity and caspase-dependent cellular responses.

The patient benefit

Better understanding of the time and dose-dependent effects of general anesthetics on the developing brain, particularly in children who have genetic predispositions to conditions such as CHDs, will help researchers understand their role (if any) in behavioral problems often encountered by these patients after surgery.

If found to be a contributing factor, perhaps new therapies to mitigate this caspase activity might be explored to alleviate some of these adverse effects on the developing brain.

What’s next?

The authors hope to stimulate more in-depth research into caspase signaling events, particularly related to how these signaling events change when an anesthetic is introduced. Deeper understanding of how anesthetics impact caspase activation in the developing brain will allow for better assessments of the risk for children who need major surgery early in life.

Children’s National leads the way

Children’s National Hospital leads studies funded by the U.S. Department of Defense to better understand how these other roles of caspases, which until now have not been well-documented, may contribute to brain cell degeneration when activated by prolonged anesthesia and cardiopulmonary bypass during cardiac surgery for congenital heart disease.

Anitha John

Youth with heart defects need a smooth transition to age-appropriate heart care, says AHA

Anitha John

Anitha John, M.D., Ph.D., director of the Washington Adult Congenital Heart Program (WACH) at Children’s National Hospital and incoming chair of the AHA Young Hearts council, served as lead author on the statement, which provides the latest evidence-based best practices for a successful transition from pediatric care to adult care.

The American Heart Association (AHA) issued a scientific statement capturing the best practices for helping children with congenital heart disease successfully transition to adulthood and receive health care tailored to their needs as they continue to age. Ensuring a smooth and supported transition and establishing relationships with these young patients as they grow into adults is key to maintaining their engagement and connection to health care decisions that will improve their long-term health and well-being.

Anitha John, M.D., Ph.D., director of the Washington Adult Congenital Heart Program (WACH) at Children’s National Hospital and incoming chair of the AHA Young Hearts council, served as lead author on the statement, which provides the latest evidence-based best practices for a successful transition from pediatric care to adult care. This work is critical given that today, thanks to the tremendous advances in care and treatment of congenital heart defects in the last two decades, there are more adults living with congenital heart conditions than children.

What this means

The AHA describes a scientific statement as an “expert analysis of current research” that “can inform future care guidelines.” This scientific statement demonstrates the scientific evidence supporting what adult congenital heart specialists have advised for years—that making sure children with congenital heart defects continue to stay engaged in their care and actively seek out health care specialized for them as they grow through adolescence and into adulthood is critical. Keeping that connection plays a pivotal role in their overall quality of life as they age.

Why it matters

Treatments and care for children with congenital heart defects has improved so greatly that, according to the AHA, “most people born with heart defects today, including those with complex heart conditions, survive past childhood and become adults.” But the same care they received as children is not enough to address their needs as adults. Adult-oriented congenital heart care can be the difference between a long and healthy life or continued health challenges and dangerous side effects. Adults with congenital heart conditions should seek out care that serves them best, and it should be accessible to everyone who needs it.

By issuing this updated scientific statement, the AHA is broadcasting the important take home message that adults with congenital heart disease and their care providers need (and should seek) access to an adult-focused program with expertise in caring for the unique challenges they face. Establishing that connection at the transition point from adolescence to adulthood can set the stage for long term engagement and health.

Children’s National Hospital leads the way

As director of the WACH program at Children’s National, Dr. John is one of the nation’s experts in care for adults living with congenital heart disease. She also leads significant patient-centered research efforts focused on understanding barriers to care and other challenges faced by these adult heart patients, including serving as co-principal investigator on one of the largest patient-centered studies of adults living with congenital heart disease, supported by the Patient-Centered Outcomes Research Institute (PCORI). The findings from these studies will help fuel further recommendations and guidelines that will improve the standards of care for these patients.

Read the AHA News overview of the Scientific Statement.

Read the Scientific Statement from the Journal of the American Heart Association.

newborn baby

Study suggests chronic hypoxia delays cardiac maturation in CHD

newborn baby

Every year, nearly 40,000 babies are born with a congenital heart defect (CHD) — the leading cause of birth defect-associated infant illness and death.

Every year, nearly 40,000 babies are born with a congenital heart defect (CHD) — the leading cause of birth defect-associated infant illness and death. An event that may contribute to cyanotic CHD is the lack of oxygen, known as hypoxia, before and after birth, impacting gene expression and cardiac function that delay postnatal cardiac maturation, according to a new pre-clinical model led by researchers at Children’s National Hospital.

Single ventricle, transposition of the great arteries, truncus arteriosus and severe forms of tetralogy of Fallot, such cyanotic congenital heart diseases have lower circulating blood oxygen levels. The lack of oxygen in the blood begins prenatally and continues after birth until definitive repair, suggesting a delay on cardiac maturation.

There is little research on the underpinnings that explain the lack of oxygen’s effects on the developing heart, which could help inform adequate therapies in the pediatric population to promote cardiovascular health across the lifetime. The researchers developed the first pre-clinical model that explores the effects of chronic hypoxia in perinatal and postnatal stages on the developing heart under conditions seen in cyanotic CHD.

“To the best of our knowledge, ours is the first study to perform complete gene expression arrays on animals after perinatal hypoxia,” said Jennifer Romanowicz, senior noninvasive imaging fellow at Boston Children’s Hospital and lead author of the study. “Not only did these studies allow us to determine the effects of hypoxia on heart development, but the detailed results of our study will be available to other researchers to independently address other questions about perinatal hypoxia and heart development.”

The study published in the American Journal of Physiology: Heart and Circulatory Physiology suggests that chronic lack of oxygen alters the electrical properties of heart tissue, called the electrophysiological substrate, and the contractile apparatus, a muscle composed of proteins that control cardiac contraction. Multiple genes involved with the contractile apparatus were expressed differently in the non-human subjects.

“What was remarkable was that most abnormalities normalized after the animals recovered in normal oxygen levels,” said Romanowicz. “This is an optimistic sign that early repair of cyanotic congenital heart disease may allow the heart to finish development.”

The researchers placed pregnant non-human subjects in hypoxic chambers starting on embryonic day 16, mimicking the second trimester in humans. The same subjects gave birth in the hypoxic chambers, and the newborns were kept there until postnatal day eight when the heart muscle maturation is nearly complete. To understand how human infants recover with normalized oxygen levels after surgical repair of cyanotic CHD, the researchers moved hypoxic subjects to normal oxygen conditions for recovery and tested again at postnatal day 30.

“Next steps include using a pre-clinical model of cyanotic congenital heart disease that more accurately represents human neonatal physiology,” said Devon Guerrelli, Ph.D. candidate at Children’s National. We plan to work with the cardiac surgery team at Children’s National to investigate changes in the myocardium due to hypoxia in pediatric patients who are undergoing surgical repair.”

Nikki Posnack, Ph.D., principal investigator at Sheikh Zayed Institute for Pediatric Surgical Innovation and Nobuyuki Ishibashi, M.D., director of Cardiac Surgery Research Laboratory at Children’s National, led and guided the team of researchers involved in the study.

Nikki Gillum Posnack

Research team develops new and improved method for studying cardiac function

Nikki Gillum Posnack

While researching how plastic affects heart function in sensitive populations, such as children born with congenital heart defects, Children’s National researcher Nikki Posnack, Ph.D., led a team that developed a new and improved, replicable method of performing simultaneous dual optical mapping to examine electrical activity and calcium for the study of cardiac function.

Since arriving at the Sheikh Zayed Institute for Pediatric Surgical Innovation, researcher Nikki Gillum Posnack, Ph.D., a principal investigator with the institute and assistant professor of pediatrics at the George Washington University School of Medicine and Health Sciences, has been focused on examining how exposure to plastic affects heart function in sensitive populations, such as children born with congenital heart defects. She performs optical mapping to conduct this research, but the industry standard approaches of either using dual cameras or sequential single cameras were cost prohibitive and technically challenging while also diminishing the quality of the imaging results.

Fast forward to July 2019 when Dr. Posnack and her team published “Plasticizer Interaction With the Heart” in the journal Arrhythmia and Electrophysiology, which used imaging techniques to reveal the impact of plastic chemicals on the electrical activity of the heart. Dr. Posnack’s laboratory has since expanded this technique and revealed a new replicable method of performing simultaneous dual optical mapping to examine electrical activity and calcium handling in the heart.

Sharing a new method for studying cardiac function

This groundbreaking method is itself the focus of a new BMC Biomedical Engineering journal article titled “Lights, camera, path splitter: a new approach for truly simultaneous dual optical mapping of the heart with a single camera.”

The article compares and contrasts the current standard for dual camera simultaneous configurations and single camera sequential configurations to Dr. Posnack’s new single camera simultaneous configuration.

Simultaneous dual mapping systems use two probes and dual dyes – one for electrical voltage and the other for calcium. While dual-dye combinations like Di-4-ANEPPS with Indo-1, Di-2-ANEPEQ and calcium green have been developed to separate fluorescence signals by emission, these dye combinations can have spectral overlap, creating the need for non-ideal emission bandpass to negate spectral overlap and/or the inclusion of a calcium probe with an inferior dissociation constant. Additionally, dual-sensor systems require proper alignment to ensure that fluorescence signals are being analyzed from the same tissue region on each individual detector, which could lead to erroneous results. The dual-camera optical setup is expensive, technically challenging and requires a large physical footprint that is often not feasible for basic science and teaching laboratories conducting critical research.

As an alternative, some researchers use a single camera configuration to sequentially image the voltage and calcium probes using excitation light patterning. This approach also has limitations. These single-sensor designs use dual-dye combinations that require two or more excitation light sources, but share a single emission band. Like the dual camera system, this platform design is also technically challenging since the different excitation light wavelengths require light source triggering, camera synchronization and frame interleaving. Due to timing coordination, decreased frame rates, excitation light ramp up/down times and shutter open/close times, single system setups require shorter exposure times compared to dual sensor setups, diminishing the signal-to-noise quality without offering the same temporal fidelity. There is a cost advantage to the single camera system, however, because the additional camera is often one of the most expensive components.

This new single camera, simultaneous dual optical mapping approach is the first multiparametric mapping system that simultaneously acquires calcium and voltage signals from cardiac preparations, using a commercially available optical path splitter, single camera and single excitation light. Using a large field of view sCMOS sensor that is faster and more sensitive, this configuration separates the two emission bands for voltage and calcium probes and simultaneously directs them to either sides of the single, large camera sensor. This protocol employs a commonly used dual-dye combination (RH237 and Rhod2-AM). In contrast, other protocols may require genetically-encoded indicators or fluorescent probes that are not yet commercially available.

The team validated the utility of the approach by performing high-speed simultaneous dual imaging with sufficient signal-to-noise ratio for calcium and voltage signals and specificity of emission signals with negligible cross-talk. Demonstrating the need for simultaneous electrical and calcium sensors, they found that when ventricular tachycardia is induced, there is spatially discordant calcium alternans present in different regions of the heart even when the electrical alternans remain concordant.

Having eliminated the second camera as well as the need for multiple excitation light sources, light pattering and frame interleaving, this system is more cost effective, simpler, and can be easily setup by various types of researchers, not just those with engineering backgrounds.

With a limited research budget and a background in physiology, Dr. Posnack worked collaboratively with her post-doctoral fellow Rafael Jaimes III, an engineer in the Sheikh Zayed Institute for Pediatric Surgical Innovation, to develop a cost-effective system that would enable her to truly study the effects of plastics on the heart.

Multidisciplinary approach

“We’re fortunate to have a multidisciplinary team in the Sheikh Zayed Institute so that I could work with an engineer to develop the technology and system we needed to propel our research,” said Dr. Posnack. “There are so many researchers who have the science background, but not necessarily the technical aptitude, and they get stymied in their research, so we’re proud that this paper will help other researchers replicate the system to study cardiac function.”

The research paper was funded by a grant from the National Institutes of Health as well as support from the Children’s Research Institute, Children’s National Heart Institute and the Sheikh Zayed Institute for Pediatric Surgical Innovation.

The applications for this optical mapping system are significant and Dr. Posnack has been consulted by other research teams looking to implement it in their labs. Additionally, Dr. Posnack has collaborated with several neuroscience teams at Children’s National Hospital, including one that is investigating the effects of hypoxia on brain and heart development, and another that is interested in using image modalities and data processing to analyze calcium as an indicator of neuron firing.

Dr. Posnack continues to use this new dual optical mapping system to further her research as she anticipates the publication of a new article about age-dependent changes in cardiac electrophysiology and calcium handling.

heart and medical equiptment

How much do you know about congenital heart defects?


Newborn pulse oximetry screening: which algorithm is best?

Gerard Martin

There’s a consensus that Pulse oximetry screening (POS) is a proven way to find critical congenital heart defects. But, screenings, specifically the algorithm used, vary. Gerard R. Martin, M.D., Medical Director of Global Health at Children’s National Health System, and Andrew K. Ewer, MD, explore which algorithm is best in their just-published article in Pediatrics. Read more.