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Robert D.B. "Jake" Jaquiss, M.D.; Chief, Pediatric and Congenital Cardiothoracic Surgery, Arkansas Children’s Hospital; Professor, Department of Surgery, University of Arkansas for Medical Sciences College of Medicine Heterotaxy (derived from the Greek words heteros meaning other and taxis meaning order) is a medical term used to denote abnormalities of “sidedness” or laterality of the internal organs, including the heart and blood vessels. In the normal anatomic arrangement, the external appearance is one of right-left symmetry, so that the right side of the body appears to be a mirror image of the left side. In contrast, all of the internal organs are actually asymmetric, whether single (for example the heart) or paired (for example, the lungs). During usual fetal development, as the organs grow in size and complexity, they also develop laterality so that the heart comes to lie in the left side of the chest and the liver on the right side of the abdomen. Conversely, if there is an abnormality in the development of laterality of an organ, it should not be surprising that there may be a corresponding abnormality in the development in the size or function of the organ. Likewise, if there is an abnormality in the development of the laterality of one organ system, there is frequently, but not always, abnormal development in the laterality of other organ systems.
Often
the abnormality takes the form of bilateral symmetry
of internal organs so that both lungs appear like a normal
right lung or both cardiac atrial appendages take the shape
of a normal left atrial appendage. In such cases, location
of the spleen is often indicative of the type of lateralization
abnormality that is present, since it is normally a left
sided structure. In general, although no two children with
heterotaxy are exactly alike, there are three broad types
of heterotaxy: situs inversus wherein the organs are on exactly
the opposite side of the body from the usual arrangement,
polysplenia wherein there tends to be bilateral left-sidedness,
and asplenia with bilateral right-sidedness. In this article,
I will focus on the latter two sub-types of heterotaxy, since
situs inversus is less commonly associated with cardiac abnormalities.
Polysplenia The term polysplenia is used interchangeably
with the term "left atrial isomerism" to indicate a
circumstance of bilateral left-handedness. The associated
cardiac anomalies tend to be less severe than in asplenia
and less commonly include “single
ventricle” physiology.
In polysplenia, there are frequently bilateral superior
vena cavae and the inferior vena cava is typically “interrupted”,
with return of inferior vena caval blood to the right
superior vena cava. The pulmonary veins usually return
directly to the heart, although they may return to
either or both atria. There are typically two well-developed
ventricles and only about one-third of patients have
a complete atrioventricular canal defect. Outflow obstruction
is frequent, although less so than in asplenia, and
usually involve sub-pulmonary narrowing. A “typical” heart
seen in a patient with polysplenia is shown in diagrammatic
form in Figure I. Important non-cardiac abnormalities
include a right sided-stomach in approximately half
of polysplenia patients with a midline liver in about
a third. There is extra-hepatic biliary atresia in
as many as 10 percent of polysplenia patients and intestinal
malrotation, with the implied risk for volvulus, occurs
in about 10-30 percent of polysplenia patients.
Asplenia is the term used to indicate bilateral right-sidedness, as is the term right atrial isomerism. The term “Ivemark syndrome” is also used to describe the condition, which was first described in 1959 and is often felt to convey a worse prognosis than polysplenia. In part, this relates to the fact that more than half of asplenia patient have functionally univentricular hearts, and that the majority have anomalous pulmonary venous drainage. The abnormal pulmonary venous drainage is not infrequently of the mixed variety and may be obstructed, both of which features are known to be associated with worse outcomes. There are usually bilateral superior vena cavae, but the inferior vena cava is normally not interrupted. The majority of patients with asplenia have complete atrioventricular canal defects, and the vast majority have obstruction to pulmonary outflow. An example of a heart which might be encountered in asplenia syndrome is shown diagrammatically in Figure II. The most common significant extracardiac abnormality is intestinal malrotation in about a third of patients with asplenia. Midline abnormalities such as fused adrenal glands, hypoplastic or horseshoe kidney and anal atresia are rare in asplenia, but much more common than in the general population. The absence of splenic tissue is also associated with greatly increased susceptibility to bacterial infection, and such children require lifelong antibiotic prophylaxis.
Figure 1 Typical Polysplenia Heart
The figure shows an interrupted inferior vena cava, with blood carried from below the diaphragm to the superior vena cava by the azygous vein. There is also obstruction below the pulmonary artery and an atrioventricular canal defect depicted by the absence of the upper ventricular septum and the lower atrial septum. Abbreviations AZ-azygous vein, HV-hepatic vein, LV-left ventricle, CA-common atrium, PA-pulmonary artery, AO-aorta, RV-right ventricle, LPV-left pulmonary vein.
Figure II Typical Polysplenia Heart
Pediatric Cardiac Intensive Care Medicine: The Evolution of a New Sub-Specialty in Pediatrics
Adnan T. Bhutta, M.D., M.B.B.S., F.A.A.P.; Co-Medical Director, Cardiovascular Intensive Care Unit, Arkansas Children’s Hospital; Instructor, Pediatric Critical Care Medicine and Cardiology, University of Arkansas for Medical Sciences College of Medicine. The 25th Anniversary of the Cardiovascular Intensive Care Unit (CVICU) at Arkansas Children’s Hospital is being celebrated this year. At the time of its creation, it was one of the first ICUs in the nation dedicated to the care of children with congenital heart disease. Since then, having a dedicated CVICU for the care of this population has become the norm across pediatric facilities. A cursory look at U.S. News & World Report’s ranking of the top 25 pediatric facilities in 2006 (a list that includes Arkansas Children’s Hospital) shows that about three-fourths of the hospitals listed now have a separate CVICU, a majority of them coming into existence in the last decade or two. The need for these units arose from the recognition that children with congenital heart disease have unique physiologies which require careful attention by a team of professionals intimately familiar with their diagnosis and management. No other group of patients have their circulation disrupted routinely as is done at the time of surgery in patients with congenital heart disease. Furthermore, reduced cardiac function and hypoxemia is common in this group of patients leading to alterations in function of various organ systems – a fact that is being increasingly recognized in follow-up studies of survivors with various cardiac lesions. Advances in CVICU Care
Rapid advances have occurred in diagnostic cardiology, cardiovascular surgery and intra-operative management for a variety of congenital heart conditions such hypoplastic left heart syndrome (HLHS) or transposition of great arteries (TGA). These advances have been complemented by rapid advances in the ICU management of these children, resulting in drastic reductions in both mortality and morbidity in a very short span of time. An example of such a reduction is seen in patients with HLHS. In 1994, one year after a Norwood procedure, their survival rate at leading U.S. centers was 42 percent (1). But today, that rate is above 90 percent at some hospitals, including ACH. The improved survival of patients with congenital heart disease is resulting in a demographic change in patients who are known to have congenital heart disease. A recently published study suggests that there are now as many adults as children (those under 18 years of age) with congenital heart disease (2). Furthermore, rapid changes in pre-operative and post-operative management have occurred in all facets of the care of these patients ranging from mechanical ventilation, therapies for pulmonary hypertension, inotropic and extracorporeal cardiac support, sedation and analgesia, hemodynamic and neurological monitoring and nutrition. All of these events have combined to give rise to the distinct clinical subspecialty of pediatric cardiac intensive care medicine. Cardiac intensivists have to develop expertise in pediatric critical care, cardiology, aspects of cardiac surgery and anesthesia and other sub-specialties (3). They also are now increasingly providing critical care to adults with congenital heart disease. An ability to provide comprehensive and coordinated care, an ability to manage acute hemodynamic disturbances and a proficiency in procedural skills are all essential for success in this field. Training of Pediatric Cardiac Intensivists See Reference Page
Oral Health and Congenital Heart Disease
Sana Ullah, M.D., Pediatric Cardiothoracic Anesthesiologist, Arkansas Children’s Hospital; Assistant Professor of Anesthesiology, University of Arkansas for Medical Sciences College of Medicine. “You don’t have to brush all your teeth – only the ones you want to keep” – Anon. Although not immediately obvious, there is a strong connection between poor oral hygiene and cardiovascular disease. Patients with congenital heart disease who have structural abnormalities or prosthetic materials in their hearts are especially at risk of complications. What is the link between dental and gum disease
and cardiovascular health? What is the special risk in patients who have congenital heart disease and bad teeth?
The most feared complication resulting from bad teeth and gums is infective endocarditis – an infection of the structures of the heart or blood vessels. This can be a life threatening condition which requires urgent treatment with powerful antibiotics and even surgery to cut out the infected tissues. Having bad teeth is the most common predisposing factor for infective endocarditis in patients with congenital heart disease. Several studies have shown that dental caries and poor oral hygiene is more prevalent in patients with congenital heart disease compared with normal controls, which further increases the risk. How do bad teeth and gums cause infective
endocarditis? Are there any special concerns for patients
having cardiac or non-cardiac surgery?
Are there any specific measures taken in the
peri-operative period? What can be done to improve oral health in patients with congenital heart disease?
Increasing awareness of the problem is the first step. Several studies have shown that up to 50 percent or more of parents are unaware of the risk of endocarditis associated with congenital heart disease. Even a significant proportion of adult patients with congenital heart disease have inadequate knowledge of their condition. All caregivers should try to educate patients and parents about the importance of regular dental check-ups and good oral hygiene. Parents should be encouraged to help their children with brushing their teeth. Patients coming for scheduled clinic visits should have their oral cavities examined routinely and take the steps necessary if problems are identified. This is especially important if there is upcoming surgery. Anesthesiologists performing a preoperative airway evaluation should also look for evidence of dental problems such as carious or loose teeth and gum inflammation. Patients should be registered with a dentist and should have check-ups every six months. See Reference Page
Sylvia S. Angtuaco , M.D., Pediatric Cardiologist, Arkansas Children’s Hospital; Associate Professor of Pediatrics, University of Arkansas for Medical Sciences College of Medicine. After a child is diagnosed with congenital heart disease, the question parents most often ask is, “Will my child be able to lead a normal life?” That is immediately followed by another concerned inquiry: “Can my child play sports?” These questions are not unexpected. In a society in which parents’ water cooler conversations frequently revolve around the previous day’s sports highlights, in which it is a mother’s badge of courage to be a “soccer mom” and in which children are part of their schools’ pep rallies from the earliest grade levels, a “normal” child is expected to be interested in one sport or another. This question should actually be welcomed. The growing obesity epidemic can be prevented by exercise, even light activity. Obesity, in and of itself, has been linked to ventricular remodeling and dysfunction even in children with “normal” hearts. A parent’s false perception of their child being a “cripple” can result in turning their child into a true “cardiac cripple”. Physical, social and emotional development can be greatly influenced by the parent’s understanding of their child’s physical abilities and limitations. Each child with a heart condition should, of course, be assessed by their pediatric cardiologist prior to sports participation. Patients need to be screened for syncope, palpitations and chest pain, familial arrhythmias, sudden cardiac death and cardiomyopathies, hypertension. Echocardiography is essential for assessing degrees of severity, ventricular dilation/ hypertrophy and systolic/diastolic function. Holters screen for arrhythmias. Exercise testing can determine a child’s limitations or cardiopulmonary reserve and screen for exercise-induced arrhythmia. Associated Risks
Sudden death risk is difficult to assess. It is quite easy to fear because it usually happens to healthy appearing athletes in high dynamic intensity sports like basketball and football. The most common causes of this in children are long QT syndrome and hypertrophic cardiomyopathy. Late unpredictable sudden death does occur in children with congenital cyanotic disease (especially Tetralogy of Fallot and Transposition of the great vessels after atrial “repair”) and left heart obstruction. It is reassuring that the risk in other post-operative defects is not much higher than in the normal population. The other reassuring thing about sudden death in athletes is that it is not common and affects one in 200,000 (or five per million) high school athletes each year. In our country, significant cardiac lesions are fortunately rarely undetected and therefore, rarely left unrepaired. Children who have undergone repair and who have no significant residual lesions can frequently participate in all sports, even in competitive sports. Competitive sports are generally not recommended for children with evidence of pulmonary hypertension, ventricular dilation/hypertrophy/dysfunction, cardiomyopathies, single ventricle physiology or systemic right ventricles, frequent or serious arrhythmias, and coronary artery disease. Most of the others can enjoy social and recreational sport activities with emphasis on the word “enjoy”. It is, for us, usually an indication to intervene when a child is unable to play anymore. Children with residual shunts probably should be wary of sports that involve rapid environmental pressure changes found in mountain or aerial sports and scuba diving because of the possibility of paradoxical emboli. The same thinking should caution against choosing a sport that involves intense or sustained Valsalva type maneuvers such as weightlifting and wrestling. Common sense dictates that contact sports should not be undertaken by patients receiving anticoagulation and those who have pacemakers. Those who have conduits also are advised against contact sports. Patients with Marfan Syndrome are known to have increased risk of aortic dissection and should also avoid these. We must remind families that collision injuries occur not only with intentional contact sports such as football, soccer, boxing and martial arts, but also in sports that are at risk for accidental falls or “wipe-outs”. These include gymnastics and racing that uses equipment (cars, cycling, skiing, boarding, etc.). Mild valvar stenosis and insufficiency usually allows full participation in most competitive sports. As the degree severity increases, the dynamic and static quality of the sport needs to decrease. Both the patient and his family need to decide whether to continue the sport in a recreational fashion or change their chosen sport.
Appropriate Activities When we tell our patients that competitive sports are not a good idea but “self-limited activities” are, they often wonder what we mean. Babies and young children can usually tell when they have reached their maximum physical capacity; they therefore “self-limit”. As a child gets older, the need to compete may increase. In early childhood, there is rarely the competition that exists when organized sports become more formal, usually at around 12 years of age. Almost all sports played prior to middle school and junior high, being recreational in level, are usually “safe” for the children. Families do need to be aware of the existence of “hypercompetitive” coaches. In those who have difficulty in “self-limiting” the intensity of their sports participation, one guideline is to stop the activity when breathing prevents them from talking comfortably. Parents should be offered anticipatory guidance regarding the possibility of progression of their child’s defects. Parents can then steer their children away from sports that they may eventually have to refrain from. This can prevent significant disappointment for both the child and their family. The bottom line: Children with heart disease need a thorough evaluation by their pediatric cardiologist. Parents should understand their child’s heart condition and limitations. Thoughtful consideration and selection of appropriate sports and activities can provide most children who have heart disease with fitness and fun, just as in children with “normal” hearts. See Reference Page
Spotlight on Kathy Sleeker, Cardiac Sonographer
What is your role at ACH and how long have you
worked here? Why is your job rewarding? How did you become interested in pediatric
cardiology or cardiovascular surgery? What do you want people to know about the Heart
Center at Arkansas Children's Hospital? What do you enjoy most about working with children? What has been your most memorable moment working
in the Heart Center at Arkansas Children’s Hospital?
Spotlight on Selina Porter, C.V.I.C.U. Secretary
What is your role at ACH, and how long have you worked here? Why is your job rewarding? How did you become interested in pediatric cardiology or cardiovascular
surgery? I’ve always desired to become a nurse, and I can
truly say that in life everything happens for a reason.
In 1992, I was accepted to Baptist School of Nursing; while in school
orientation, I received a disturbing phone call, from a family member stating that
my grandfather had been rushed to the emergency room and was getting ready
to undergo surgery. My grandfather had to have a quadruple
bypass. After a speedy recovery, a month later my grandfather
was diagnosed with Lou Gehrig’s Disease. Overnight, things changed
for my entire family and certainly for my grandfather, a man who exemplified what
ACH stands for today: care, love and hope! What do you want people to know about the Heart Center at Arkansas
Children's Hospital? What do you enjoy most about working with children? What has been your most memorable moment working in the Heart Center
at Arkansas Children's Hospital? What is your greatest professional achievement?
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About Us | Heart Health | Team | Your Visit | Outpatient | Resources | Contact | Home | Site Index Arkansas Children's Hospital, 800 Marshall St., Little Rock, AR 72202-3591 (501) 364-1100 or TDD (501) 364-1184 |
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