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Heart Murmurs and Congenital Heart Disease 

Left to right shunts. I’m going to talk about atrial septal defects and ventricular septal defects and patent ductus arteriosus. In general atrial septal defects are one of the most common causes of congenital heart disease. It’s more frequent in females with murmers. It’s usually sporadic but it can be genetic. There are families that have atrial septal defects that run in the their families and the gene has not been identified, but it’s important to ask about a family history.

How they present; most are asymptomatic. They do present with a murmer. The murmur unfortunately may sound functional. The symptoms may increase in late childhood and they may be symptoms of dyspnea on exertion or just general decreased exercise tolerance. Teenagers can present with pulmonary vascular obstructive disease with atrial septal defect. It’s been said that it only presents in later adulthood but we have seen young teenagers, as young as 17, with irreversible pulmonary vascular disease. We have also seen it in infants unfortunately. The etiology is entirely unknown. As far as the physical examination, they are usually asymptomatic, quite healthy, and generally have no symptoms as I mentioned.

Here’s an example of an older child with an atrial septal defect. You can see that the heart is large but it has more of a roundish appearance to it. It is not huge but it is definitely large. The pulmonary artery is also increased. There are increased pulmonary vascular markings. The right atrium is a bit prominent and the right ventricle is also lifting up the apex.

The echocardiogram in atrial septal defect is diagnostic. You do not need a cardiac catheterization unless you are concerned about the pulmonary vascular resistance. As I mentioned previously, the pulmonary vascular resistance is usually not elevated until at most early teenage, or later teenage years. However they have been seen in young infancy and so if there is some concern about the pulmonary vascular resistance then a catheterization.

The treatment usually is nothing. As I said, there are usually no signs or symptoms. Digoxin, diuretics may be used if congestive heart failure is present, such as there may be in the older child. However, again if this is present the patient should be treated more aggressively, namely by surgery. We tend to close even the smaller defects in females. We wait until they are older in order to allow the atrial defect to close, but we close the small defects in order to prevent right to left shunting in pregnancy associated with emboli. Amniotic fluid emboli. The medium to large defects, we have chosen about 4-5 years - obviously sooner if congestive heart failure.

The natural history as I said is there is usually a benign course. No symptoms until usually later adulthood. There can be symptoms in infancy. Spontaneous closure does occur. There are a lot of books that will say a secundum ASD will not close.

Going on to ventricular septal defects. Generally it’s the most common congenital cardiac malformation. It’s classified by its anatomic location but primarily by its physiologic state, as far as what you have to do about it. There is a small defect with low pulmonary vascular resistance, moderate defects and large defects and large defects.

In marked large defects there is a murmur present. It may not be as loud. You may have a history of the murmur being present from as early as 2-3 days of life, when the pulmonary vascular resistance has dropped, and/or there may be evidence of congestive heart failure. The physical findings; there is significant failure to thrive.

When you think of a ventricular septal defect, most of us think of the blood going from the left ventricle to the right ventricle. Yes it does eventually. If you think about the first couple of heart beats both ventricles are contracting at the same time, so that the pulmonary valve is open, so the blood is really going from the left ventricle to the pulmonary artery.

Patent ductus arteriosus; in general it’s a two stage closure post-natally. The mechanisms are not understood. It is considered pathologic if it is patent after about 1-2 weeks and the incidence is higher at high altitudes, greater than 5,000 feet.

The treatment; fluid restriction and diuretics, correction of the metabolic abnormalities and so forth, improve the symptoms but aren’t actual therapeutic interventions. Again, if you for some reason don’t have indomethacin at your hospital.

As far as term infants, the presentation depends on the size of the shunt and the pulmonary vascular resistance. With a small shunt there may be no symptoms and a murmur only. The patient often initially is healthy, has a short systolic murmur at the upper left sternal border that becomes more typical when they are older.

For a moderate shunt you may have congestive heart failure by 2-3 months and the usual findings of congestive heart failure; tachycardia, tachypnea, again the bounding pulses, progression from systolic to a continuous murmur and ejection clicks are very common.