Healthy Human Heart
Prevalence of CHD in India
While there have not been many studies done on the prevalence of CHD in babies born in India, the data from the few studies done indicate that the numbers are far greater than the current statistic of 9 out of 1000 new-born babies having CHD in the developed world. Early diagnosis with routine follow-up care is crucial for the lifelong health of these children.
For more information on the status of congenital heart defects in India, please read the following article:
"Congenital Heart Disease in India: A Status Report" - Prof. Anita Saxena, Professor & Head, All India Institute of Medical Sciences, New Delhi, India
THE HUMAN HEART
The human heart is a complex organ, often beating unheard but accomplishing life-sustaining functions every minute of our life. This muscle, about the size of a fist, is made up of four chambers and four valves. The right atrium and the left atrium are the two top chambers of the heart. The right ventricle and left ventricle are the two bottom chambers of the heart. The four heart valves are the tricuspid valve, mitral valve, pulmonary valve, and aortic valve. The tricuspid valve is located between the right atrium and the right ventricle. The mitral valve is located between the left atrium and the left ventricle. The pulmonary valve is located between the right ventricle and the pulmonary artery, the blood vessel that delivers oxygen-poor blood to the lungs. The aortic valve is located between the left ventricle to the aorta, the large blood vessel that delivers oxygen-rich blood to the body.
*Image Credit CHD-Doodle
Blood delivers oxygen to all the different organs in the body then returns to the heart through large blood vessels connected directly to the heart, the superior vena cava (from the upper body) and inferior vena cava (from the lower body). These two blood vessels connect to the right atrium, the upper right heart chamber. The oxygen-poor blood travels through the tricuspid valve then to the right ventricle, which pumps the blood into the lungs through the pulmonary valve and into the main pulmonary artery. The main pulmonary artery divides into the right and left branches and further divides into smaller branches, like a tree. In the lungs, the blood picks up oxygen, becoming oxygen-rich blood. This blood then travels from the lungs through the pulmonary veins back into the left atrium through the mitral valve, then down to the left ventricle. The left ventricle pumps the oxygen-rich blood through the aortic valve and then to the aorta, which delivers blood to the body.
Here is a video on how a healthy heart works: View here
The blood pressure in the lungs is normally much lower than the pressure measured in the rest of the body. Typically, the pressure in the lungs (or pulmonary blood pressure) is about 3-4 times lower than the pressure in the body (or systemic blood pressure). For example, when the child gets her blood pressure measured on her arm, that blood pressure is the systemic blood pressure. The systolic pressure (top number on the blood pressure reading) is about 3-4 times as high as the systolic pressure in the lungs. The right ventricle, which delivers blood into the lungs, is designed to pump against low pressure. The left ventricle, which delivers blood to the body, is designed to pump against the higher blood pressure.
Some congenital heart diseases may cause the blood pressure in the lungs to abnormally increase, putting extra work on the right ventricle. This problem can also occur on the left side of the heart, with the systemic blood pressure increasing due to hypertension (as is commonly seen in adults) or narrowing of the aorta or aortic valve. These problems can cause the blood pressure to rise, which makes the left ventricle work harder. If the right ventricle or left ventricle has to pump against abnormally high pressures for a long period of time, the muscle will become dilated or enlarged and the muscle walls will become thick. With these two features, the ventricle will not work properly and eventually lead to heart failure.