Children´s Heart Center Linz - Diagnosis of Congenital Heart Defects

ECG - Electrocardiogram
Electrodes are placed on each extremity and on the chest wall. They record the electrical activities, which are produced by the heart muscle, and a tracing is generated and printed on paper, which is interpreted by the physician. This tracing contains information about the position of the heart inside the thorax, muscle mass and size of each respective cardiac chamber as well as cardiac rhythm.

Stress Test
The patient is put on a treadmill, where he has to perform standardized or maximal exercise. Continuous monitoring of the ECG, blood pressure and rhythm give information about exercise capacity e.g. after or before cardiac surgery. This examination lasts about an hour altogether and can be performed at our institution on in- or outpatients. Patients should be 130 cm of length minimum.

Holter - ECG
Holter (24 hour) ECG is routinely recorded in our institution before and after cardiac surgery, as well as in patients where arrhythmias are suspected.

Children older than 1 year of age, ambulatory Holter is offered – you have to ask for an appointment first (Tel.: +43 / (0)732 6923 2346)

Currently we are using three recorders (lifcard 3 Reynolds Medical). These recorders are powered by small batteries and 15 cm x 9 cm x 2,5 cm of size. Only three small electrodes fixed onto the chest wall are required. As all this equipment weighs only about 300g, the children usually have no problems with their activities.

Recorded data is then transmitted, saved and analyzed on a computer.

Echocardiography
Ultrasound waves of high frequency (3 – 10 MHz) are transmitted into the chest. The reflections are used to generate a real time picture of the beating heart. This examination is completely harmless and painless. The physician gets information about the size and function of the cardiac chambers and valves and he is able to see even small holes or abnormally connected veins or arteries. Doppler ultrasound (you can hear it or see a color-coded picture) adds information about blood flow velocity and direction. Even complex heart defects can be diagnosed by ultrasound alone and in many cases a cardiac catheterization can be omitted.

Fetal Echocardiography
This technique can be safely used also in unborn children as early as 16 weeks of gestation. Cardiac defects and rhythm disorders can be assessed or ruled out. Indications are if parents had a former child with congenital heart disease, maternal diseases like diabetes or if other organ defects are present. A close cooperation between obstetrician and pediatric cardiologists in our institution guarantees optimal information of the parents and optimal perinatal management (pregnancy, delivery, transfer of the baby, neonatal intensive care and, if necessary, neonatal cardiac surgery)

Transesophageal Echocardiography
Sometimes it may be very difficult to see all cardiac details during a transthoracic echocardiography (abnormal position of the heart, no access e.g. in the operating room or intensive care units after surgery). In these cases a small and flexible ultrasound probe is inserted into the esophagus and pushed down till a good picture of the heart can be obtained. This procedure is also performed on an outpatient basis most commonly using a short general anesthesia. Therefore the patient should not eat or drink at least 6 hours before admission.

24-Hour Blood Pressure Monitoring
In close cooperation with the internal department of our hospital, we perform these blood pressure measurements on in- or outpatients. A usual blood pressure cuff is put on one upper arm. Blood pressure measurements are automatically performed each 15 or 30 minutes for 24 hours and recorded into a small, walkman-like apparatus. So it should be no problem for the children to perform usual exercise. Again data is transferred, saved and analyzed on a computer afterwards. Information is obtained regarding minimal and maximal blood pressure, blood pressure during exercise and the relation between day and night.

What is cardiac catheterization ?
Cardiac catheterization means the introduction of small catheters through a percutaneous access mostly in a femoral artery or vein and pushing them forward to the chambers of the heart.

Who requires cardiac catheterization ?
Patients with unoperated congenital heart diseases should undergo cardiac catheterization if non-invasive investigations do not provide a precise definition of the severity of the disease. In some complex cardiac malformations cardiac catheterization is a helpful tool in the postoperative follow-up.
Infants with certain heart defects can be managed without cardiac surgery by occluding atrial septal defects with umbrella-shaped devices, or by dilating contracted vessels or cardiac valves with a balloon.

At what age cardiac catheterization can be carried out ?
At every age from newborn infants to adulthood, in infants routinely under anaesthesia.

What examinations prior to cardiac catheterization are necessary ?
Patients are admitted one day prior to catheterization. There will be a comprehensive discourse with the parents to clarify the techniques, benefits and risks of the investigation. Clinical examination and some tests like blood samples, an echo cardiogram, an ECG and a chest-X-ray will be carried out routinely to exclude contraindications like acute infections.
After midnight patients will be held without oral intake, whereby little infants receive infusions to avoid dehydrations and hypoglycaemia.

Where is cardiac catheterization performed ?

Cardiac Catheterization will be performed in a special locality, similar to an operation-room called "Cath Lab”. Patients lie on a mobile table around which the angiography equipment with the X-ray is installed. On various displays the obtained pictures and data can be seen and estimated.

Who performs cardiac catheterization ?

Cardiac catheterization is teamwork. During introduction and termination of anaesthesia the pediatric nurse takes care for the patient. Anaesthesia will be guided continuously by the anaesthetist. Catheterization itself is performed by the pediatric cardiologist and his assistance, guiding the catheters and instruments and handling the x-ray equipment.

What are the risks of cardiac catheterization ?

Cardiac catheterization is an invasive investigation involving some well defined risks which have to be carefully considered prior to the examination. As in every invasive procedure there is a risk of bleeding as well as infection, further on transient cardiac arrhythmias or allergic reactions on contrast fluid may occur.
Exact management and taking all precautions make severe complications in cardiac catheterization to events rarer than 1 of 1 thousand.

How long will cardiac catheterization last ?
Cardiac catheterization procedure will last about 2 hours, plus 1 hour for the preparations, therefore the estimated time the patient is in the Cath Lab will be approximately 3 hours. In case of therapeutical catheterization or if very little or very sick infants are investigated the whole procedure will exceed to 4 hours or more.
After the examination the patients are monitored beneath the Cath Lab until they are fully awake again before they are transferred back to the normal ward. Newborn or critical ill infants will be admitted in the Intensive Care Unit.

How long will patients stay in hospital after cardiac catheterization ?
After routinely in healthy patients performed catheterization, the children will be demitted home next day. If some therapeutical interventions have been done postoperative stay will be 2 days. Preoperative catheterizations are usually done one day prior to the operation.

What about the parents during the examination ?
Parents are invited to guide their children to the Cath Lab until the moment of falling asleep and to welcome them again in the anteroom when they wake up again. There are also accommodations for both mother (or father) and the child on the normal ward.

How is cardiac catheterization carried out ?
Under full anaesthesia small and flexible catheters are introduced to a usually femoral vein and artery over a percutaneous access. Then the catheters are slightly pushed forward into the atria and chambers of the heart.
In the sections reached by the catheter, the cardiologist takes blood samples, estimates pressure values and makes the reached segments visible by injecting contrast fluid. The obtained pictures, films and data are shown on several screens and electronically computed and saved for later analysis.
When the examination is finished the catheters and accesses will be removed and a pressure dressing is applied. The patient will be transferred to the anteroom, where the pediatric nurse and the parents are waiting and where first results can be discussed.

Can cardiac catheterization replace cardiac surgery ?
Today certain cardiac malformations can be treated by therapeutical cardiac catheterization without surgical opening of the chest and without the need of the heart-lung-machine.
Contracted vessels or cardiac valves can be dilated by filling an introduced balloon under high pressure, narrow vessels also can be widened permanently by implanting flexible hoses, called "stents”.
Recently defects in the septum of the cardiac fore chambers can be occluded by interventional catheterization with an umbrella-shaped device. Finally the closure of a persisting Ductus arteriososus – a little vessel usually closing spontaneously after birth and involving the risk of endocarditis if it remains open – can be successfully performed by embolizing it completely with a little coil.

What are the benefits of closing a defect in the septum of the fore chambers by interventional catheterization?
There is no surgical opening of the chest and therefore a diminished risk of bleeding, infection and there will be no scar. There is no cardio-pulmonary-bypass and there is a markedly reduced stay in hospital from approximately 10 to 3 days.

In the cathlab