By Tal Barak with Dr. Avraham Lorber, Director, Pediatric Cardiology, Meyer Children’s Hospital, Rambam Medical Center

What is a congenital heart defect?
A congenital heart defect is a flaw in the structure of the heart, or of the large vessels leading to and from the heart, that impairs normal cardiac functioning. A large variety of such defects occur during the first months of pregnancy, in the course of fetal heart development. Abnormalities of morphology (structure) may include many components.

For example, the heart may be normally constructed in general despite the existence of an impairment. The heart responds to this impairment with such structural maladaptations as wall thickening or the dilatation of ventricular or atrial cavities.  Explains Dr. Avraham Lorber, Director of Pediatric Cardiology at Rambam Medical Center: "If these defects are detected and treated at a young age by surgical correction or catheterization, the heart will adapt to the new blood flow and will function as a normal or nearly normal heart. In children, adaptation to the heart's new and improved condition is very rapid, and sometimes takes place within hours."

In contrast, complex heart defects feature severely abnormal structuring and impaired functioning of major cardiac parts (ventricles, atria, valves, blood vessels, and defective communications between chambers). Catheterization and surgical interventions can restore heart function and improve a patient's quality of life. Furthermore, although some defects (e.g., single-ventricle defects) are impossible to correct, they can be palliated.

The broad range of features characterizing heart defects, and the fact that the nature of a particular impairment varies from patient to patient, means that each case is a world unto itself. For only one example, a hole between the cardiac atria or ventricles may be only a few millimeters or several centimeters in diameter, and its size and location will greatly affect the patient's degree of health and level of functioning.


What are some of the known factors for a congenital heart defect?
Of all congenital defects, heart defects occur most frequently. According to statistics, approximately 8 of every 1,000 children in the western world are born with a heart defect. In Israel, the frequency is slightly higher due to consanguineous marriage (marriage between relatives). In hospitals serving a higher than average number of consanguineous couples, the frequency of babies born with cardiac flaws can reach 2%.

Several other factors may also explain this phenomenon. Viral infection, even a simple flu or mild gastrointestinal illness, especially during the first trimester of pregnancy, can damage fetal tissue and cause impaired heart development. Dr. Lorber: "There is seasonality in the occurrence of congenital defects in general, and heart defects in particular. During the first trimester of pregnancy, there is more vulnerability to fetal defects. If this stage of pregnancy occurs during seasonal transitions, when the predisposition to viral infections is higher, the fetus is at higher risk for developing a cardiac abnormality."

Other factors that can adversely affect fetal heart development include the pregnant woman's uncontrolled diabetes, bout with rubella, consumption of alcohol, or use of drugs prohibited during pregnancy (e.g., lithium or certain anti-seizure medications). Genetic factors, too, may play a role.

However, all such factors are rare, and together explain only about 3% of cases.


Who is at high risk for a congenital heart defect?
Children belonging to certain groups have an increased risk for a congenital heart defect. For example, 2% of premature infants are born with Patent Ductus Arteriosus (PDA) and require surgical intervention, a massive 50% of children with Down's syndrome are born with cardiac abnormalities, and in vitro fertilization (IVF) carries a higher risk of all congenital abnormalities including cardiac defects.   


 What are the symptoms indicative of a possible heart defect in youngsters?
Symptoms may include the following:
• Difficulty breathing and changes in the color of the tongue and skin
• Intermittent drowsiness and excessive irritability or restlessness
• Difficulties in feeding, or heavy breathing, significant fatigue and interruptions during feeding 
• As plotted against the growth curve, a gap between a child's condition and the norm
• Consistently higher than average respiratory rate
• Difficulties during physical exertion as compared with peers

However, some of these symptoms may appear in youngsters without cardiac problems, and this is where the physician's experience plays a role in detecting or excluding the presence of a heart defect.


How are congenital heart defects diagnosed?
The physician will collect extensive information about the patient and family, perform a thorough physical exam, and give the young patient such tests as an ECG and echocardiogram, which provide data on cardiac structure and function. If necessary, further tests will be performed, among them ergometry, a Holter ECG, and CT or MRI scans.

Furthermore, 21st-century technology enables us to detect most congenital heart defects, especially the more complex ones, in utero. Theoretically, if all pregnant women underwent comprehensive ultrasound tests, it would be possible to identify most fetuses with complex heart abnormalities. In Israel, parents may consider continuing or terminating a pregnancy based on the information provided to them about the severity of a fetal cardiac defect, the options for treatment to correct the defect, and the quality of life expected for their child.
 
Dr. Lorber: "Knowledge during pregnancy of a cardiac abnormality is very valuable. It enables us to guide the parents so that the baby will be delivered in a hospital with the appropriate facilities, and to prepare the parents for the birth and for raising such a child. The medical staff can make special arrangements for delivering and treating a newborn with a diagnosed heart defect, and can prevent distress by early pharmaceutical, catheterization or surgical intervention. Such intervention may take place even only a few hours after birth. If we don't have advance knowledge of the defect, treatment will begin only after detecting symptoms of distress. In cases of delayed diagnosis, however, treatment is required not only for the congenital defect, but also for other systems damaged by the untreated, flawed heart."

Approximately 50% of babies born with a heart defect undetected during pregnancy will be diagnosed during the first week of life. Among the rest, about 60% will be diagnosed during the first months of life; the remaining 40% will be identified during periodic tests performed at various stages in life.


How is a specific type of defect diagnosed?
If the problem was not diagnosed in utero or during routine examination of the newborn, the diagnostic process will begin only after findings of function disorders are detected by the parents or the attending nurses or physician.

Diagnosis is currently based on informed use of ultrasound technology, which enables noninvasive cardiac testing and accurate evaluation of cardiac structure and function. Recently, echocardiography devices have been developed that enable real-time, three-dimensional imaging of the entire heart, which has further improved diagnostic capabilities. If other imaging modalities are required, CT or MRI yield additional precise 3-D heart models.


How are congenital heart defects treated, what are the challenges for the physician, and what is the prognosis for patients?
Specific treatment depends on the defect's type and severity. A variety of pharmaceutical, surgical and catheterization interventions enable physicians to improve a patient's functioning at a sustainable level. For example, it is possible to dilate stenotic valves using a balloon catheter or to seal leaks or congenital heart septum defects by insertion of coil stents and sealing devices. For the past decade at Rambam, pediatric cardiologists have been sealing patent arterial ducts, atrial septal defects and ventricular septal defects.

Dr. Lorber: "You have to understand that the size of a baby's or child's heart is the size of his fist. The diameters of the blood vessels leading into and out of the heart are only a few millimeters. Any movement performed during catheterization or surgery has to be very delicate and decisive. Any thrust or uncontrolled movement could cause irreversible damage. The challenge of treating congenital heart defects demands endless diligence, devotion, skill, and the collaboration of multidisciplinary professional teams."

More than 90% of children with heart defects survive stabilizing and corrective interventions, and the majority of them reach adulthood. Dr. Lorber: "A child with a heart defect can be treated and brought to a level of functioning similar to that of the healthy population. However, for some patients of all ages, no specific solution can turn them into healthy people. They need periodic evaluations, medical and family support, and recurrent interventions to optimally maintain their system and bring them to a satisfactory level of functioning."

Youngsters that do not survive are those with especially severe defects or that develop major cardiac and systemic complications during treatment -- a tragic outcome that mostly occurs when a patient's physical reserves are insufficient to sustain life during treatment. Dr. Lorber: "The members of the medical teams treating a critical patient are involved not only technically but also emotionally in every single patient, and we share the family's grief at every loss. Our grief is double because we have lost the professional battle for a patient's survival and existence and because we have lost a soul.  We try not to show our emotions because we need to function for the next patient, but we take our grief home."


What is the possibility for another heart defect in the family?
Statistically, compared with the general population, a family with a child suffering from a heart defect has a higher chance of having another child with a heart defect. A higher risk exists for certain defects and a lower risk for others, but in general, the risk is 3-6%. This is the reason that genetic counseling is recommended for families in which one child has been diagnosed with a cardiac abnormality; it is also recommended to perform a fetal heart scan during pregnancy.