India has vast population and falls low in human development indices. No wonder that every statistics at national and international level indicates our limited will power to control birth rate and under-five mortality. The cardiac diseases in children are not uncommon but usually are one of hidden contributory factors. The contemporary practices like ingestion of unprescribed medicines and herbs, tobacco chewing, bidi smoking, nutritionally deficient diet during pregnancy may have a role to play. Unavailability of epidemiological data keeps us assuming that probably we match with world data suggesting prevalence of CHDs in up to 6-7 babies born out of 1000 live birth, though we might be exceeding it.
Structurally, 4 chambers of heart (two atria or receptacles and two pumps known as ventricles) have two shared wall – inter atrial septum (IAS) and interventricular septum (IVS). The right atrium (RA) has deoxygenated blood returning from body and left atria oxygenated blood from lungs. There are pairs of valve at entrance for right ventricle (RV) – tricuspid valve and for left ventricle (LV) - mitral valve and exit (for right ventricle- pulmonary valve and for left ventricle-aortic valve) of the ventricles. The pulmonary artery connects the RV to the lungs and aorta connectsthe LV to the body. By this arrangement, a pressure difference is maintained between lungs and body.
Heart beats according to age, approximately 60-100 times in a minute. It is a muscular organ and has sophisticated conduction system which controls synchrony between the two atrium as well as two ventricles and ensures that atria and ventricle must contract at a time lag so ventricle can remain relaxed and receive blood during atrial contraction.
Lungs collaborate with heart on beat-to-beat basis. The fine tuning of heart with respiration is most refined mechanism and malfunctioning of one unit would sooner or later be reflected on mechanics of the other. So pulmonary vasculature can become thick and non -permissive to blood flow in cases where aortic pressure starts reaching to lungs like in cases of hole in heart. Actually lungs need one fifth of pressure for smooth blood flow as compare to body where normal blood flow needs a driving force of approximately 100mmHg generated during LV systole. Even diastolic pressure in aorta is much higher than that of pulmonary artery. The vasculature of the lungs has delicate membranes which help in absorption of oxygen coming into alveoli during respiration.
Diseases of the heart
With above mentioned facts, we can understand that when heart has abnormalities, it will be related to its structure, function and electrical system or conduction or all three may present at the same time. There is a possibility that lungs may get affected due to these alterations. Structural heart diseases
can be simple holes in heart or obstruction at valves and arterial lumen or it may have a composite defect involving major problems like non formation of valve or a chamber or the arteries. Without going into details of all diseases, we will examine the commonest abnormalities that is, holes in heart and recent modality of treatment in this article.
Hole in heart: Simplest defects
The common types of congenital defects include atrial septal defect (between two atria), ventricular septal defect (between two ventricles) and patent ductus arteriosus.
This hole in heart
present with high respiration and heart rate, excessive sweating
, difficult breast feeding and growth failure. Few unfortunate babies are recognised only when they have pneumonia. The routine respiratory tract infection
in these children may involve infected lungs often letting these children to become resistant to conventional treatment. These days, sensitivity level amongst paediatricians is high and they ask for echocardigraphy if they see a baby with aforesaid presentation or some times on detection of abnormal sound (murmur) in heart. Presence of the bluishness indicates more complex diseases.
These holes in heart are easily treated now and if left untreated beyond 2 years of age, they may culminate in to Eisenmenger syndrome and permanent damage to the lungs
. Though, ASDs are safe in early childhood and adolescence.
Non-surgical closure of hole in heart
The natural or spontaneous healing is possible for the holes which lead to many misconceptions in society. These holes must be adequately examined by qualified doctor
before leaving them for natural course because no medicine can heal them as being claimed by quacks.
The medicines are given only to reduce the effect of disease and decongest the lungs.
Non-surgical closure of holes means anchoring a device in the hole by angiographic method. For example, to close an atrial septal defect, we take the child to cath lab and under deep sedation we take access through femoral vein. A long sheath is placed across the defect and through it, the device which has a waist of defect size is guarded by two little larger discs on either sides. One of discs is released on left atrial side and then releasing waist at defect. The device is further brought back to release the other disc on RA side. These discs catch hold the margins to make waist sitting comfortably at defect. Now, device is unscrewed by rotating the loading cable.
The principle of device closure remains same. It is like putting a brick on hole in a wall and body does cementing over the time. A thin membrane is formed within 72 hours and within 3-6 months both sides are covered by layer of tissue. Usually we need a good weight of 6-8 kg for the procedure. All babies cannot be treated with such devices. The device closure needs margin all around so that it can hold on well without getting displaced by heart or body movements.