NEWBORN HEART MURMURS

Published: 06th December 2011
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Have you ever listened to the sound produced when you suddenly open and then close a faucet? This happens 100 times a minute in the heart and it, too, produces noise. Normally, the noise consists of two sounds that can be heard only with a stethoscope. The first is produced by the normal closing of the valves between the chambers of the heart, and the second by the closure of the valves where the blood flows out of the heart. Doctors generally refer to the two valve-closure sounds as basic heart sounds.
Rapidly flowing streams also make noise in and of themselves. Brooks babble, waves crash, electricity hums, and wind howls. Put your ear to a water pipe when the faucets are wide open and listen to the water flow. Better still, put your ear to a garden hose when the water is going full blast and hear the buzz.
Like the water pipe, the heart produces flow and the flow produces sound. Sounds in the heart that are produced by flow are called murmurs. Most flow is normal and, therefore, most murmurs are normal. Murmurs resulting from normal flow are called innocent murmurs. When the flow is abnormal, the sounds produced represent disease and are called organic murmurs.
The newborn heart produces these same normal sounds with a few variations. To understand why the newborn heart sounds different from that of an adult, you need to know how a mature heart functions. The heart is a fist-sized organ situated slightly to the left of the chest's midline. Its function is to pump blood through two separate but contiguous routes, one to the lungs and the other to the rest of the body. In order to keep these two routes separate, the heart is divided into two halves by a vertical wall, called the septum. Each half of the heart is horizontally divided in half, creating an upper chamber, the atrium, and a lower chamber, the ventricle, making four chambers in all—two atria and two ventricles.
Blood enters the right atrium after completing its delivery of oxygen to the body. This dark, used blood is emptied into the right ventricle to be pumped through the pulmonary arteries (that is, arteries that lead to the lungs). While the dark, used blood flows through the lungs, it unloads its carbon dioxide and picks up a fresh supply of oxygen to become bright red once again. This red, rejuvenated blood returns through the pulmonary veins to the left atrium of the heart. From the left atrium it empties into the left ventricle, and from there it's pumped out via the great artery, the aorta, to nourish the body. For efficiency's sake, the heart is equipped with strategically positioned valves designed to open to allow forward flow, and shut to prevent backward flow. The valves ensure that all of the blood leaving the left ventricle, for example, heads out of the aorta, instead of paying another visit to the left atrium.
This is the circulation pattern that your baby's heart is aiming for. In the beginning, however, his little heart has some brand-new routes to learn. Here's why:
Because the unborn infant doesn't breathe, there's no need for his blood to circulate through his lungs. Actually, the fetal lungs are completely collapsed and it would take a great deal of pressure to force blood through the collapsed pulmonary circulation. Because the lungs aren't in use before birth, fetal circulation goes on by means of shortcuts that route the blood to the left, "systemic" side of the circulation.
The first fetal shortcut, or shunt, as we call it, runs between the two atria. Some of the blood that has arrived in the right atrium flows directly across to the left atrium through a special, temporary opening in the septum. The rest of the blood flows from the right atrium directly downward into the right ventricle, and from there, out the main pulmonary artery. But instead of going to the lungs, which aren't yet in use, the blood is shunted via a short channel into the aorta. This second shunt, the ductus arteriosus, exists for this diversion only, and self-destructs once it's no longer needed.
At the moment of birth, however, the ductus arteriosus is wide open and functioning as a shunt.
Now comes the action; newborn murmur number one. As soon as the baby takes his first breath and starts using his lungs, he no longer needs the shunt. In fact, the ductus arteriosus becomes a liability, since it prevents some of the used blood from reaching the lungs to be rejuvenated. Mother Nature to the rescue! In response to the now improving oxygenation, the body sends a chemical message to the ductus arteriosus to get lost. (It's the old story: What have you done for me lately?) The obsolete ductus begins to thicken its muscular wall and obliterate its channel.
While this old friend of the fetus is self-destructing, however, blood continues to flow through its ever narrowing opening. The narrower the opening, the more rapid the stream and the more noise it produces. In this way, a desirable change takes place in the baby and the audible proof of this is the special sound of the newborn murmur. The process itself occurs in all normal newborns, but not every newborn will produce the musical accompaniment. Depending on the number of examinations, the noise level, and the level of the baby's activity, as many as one third of normal newborns will produce a murmur generated by the ductus arteriosus. It can be heard immediately after birth and can persist for several hours, several days, or more.
Of course, since the stimulus for closure of the ductus comes from the functioning of the newborn's lungs, the ductus may stay open for an abnormally long time if there's a problem with the baby's lungs. This is particularly apt to occur with premies who have respiratory difficulties.
Newborn murmur number two, which is heard in the hearts of as many as 55 percent of normal newborns, is also one of the most frequently heard innocent murmurs of later childhood. It's usually first heard during the first few days of life, but because it also occurs in older children.
The third common newborn murmur results from the structure of the pulmonary artery in early infancy. At birth, and for several weeks after, the main pulmonary artery, as it exits from the right ventricle, is disproportionately wider than its two branches, the right and left pulmonary arteries. Furthermore, the two branches veer off at very sharp angles from the main trunk. As a result of these structural conditions, a great deal of turbulence is created as the blood flows from the main pulmonary artery to its two branches. This turbulence sets up vibrations along the arteries going to the lungs, which can be heard as a murmur all over the baby's back.
This third murmur is called physiologic (healthy) peripheral (away from the center) pulmonic stenosis (narrowing). It's short-lived. As the right and left lungs develop, the branch arteries that lead to them widen. The arteries also widen their angle of departure from the main trunk. The turbulence decreases, and usually by three months of age this murmur can no longer be heard. The fourth innocent murmur—the ventricular septal defect (VSD)— represents a striking example of an abnormal situation correcting itself and becoming normal. This is the murmur produced by blood flow through a defect, that is, a "hole" in the wall dividing the ventricles.
The VSD is purely and simply abnormal. Fewer than 5 percent of babies are born with it and, in rare cases, it does create problems. Most often, however, these holes, which are sometimes large enough to strain a baby's heart, close up completely. Not by the hand of a surgeon. They do it entirely on their own.
We don't know exactly how often large VSDs close spontaneously, but we do know about the small VSD. By closely following babies with small VSDs, we've found that 65 percent of the holes situated in the thick muscular part of the septum spontaneously close. In the less common situation, where the defect occurs in the thin, membranous, upper part of the septum, only 25 percent close on their own. The overall spontaneous closure rate, which includes those babies whose defect position couldn't be determined, is 58 percent. The proportion of closures may, in fact, be even greater than 58 percent. We very seldom find small VSDs in adults, so it's a fair guess that virtually all of them eventually close. We know, too, that even defects in the membranous pair of the septum have better than one-in-four odds of closing on their own.

Abbas Ahmad is famous homeopath often writes articles about health and homeopathic treatment such as Fatigue and Teeth Mouth and Gums.
http://homeotreatment.com/Headachesandmigraines.htm


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