Thursday, October 27, 2011

A Newborn with a Heart Murmur

Every once in a while as I worked in the newborn nursery at the county hospital I helped staff, a newborn would be admitted to the unit who had a congenital defect.  Many of them were simple, they were what we considered minor malformations.  These were easy to take care of such as a partially formed sixth digit (which we would tie off, the extra digit would eventually fall off) or they would have somewhat of a loopy earlobe (what was called lop ear deformity).
Then there were the major congenital malformations, which could affect the child as they grew up, and for which they could need corrective surgery.  It was these infants that were generally referred over to the pediatric specialist services, based on what congential defect the infant had. 
 Just such an infant was admitted to the newborn nursery while I was on duty.  She was a cute little 7 lb. newborn of hispanic ethnicity.  Looking at her you wouldn’t think anything was wrong, she was breastfeeding just fine, was not jaundiced (yellow tinge to her skin) and was on schedule to be discharged home with her mom at 30 hours post delivery. 
I went in to do her first physical exam at 15 hours of life (she had been born the night before and spent the night with her mom in her bassinet next to her mom’s bed).  So she was a newborn that we needed to check, make sure she had received her first immunization of hepatitis B and check her bilirubin level as well as do her PKU test (heel stick test to acquire blood).

There are a few things that are done to newborns born in a hospital setting.  These include checking the newborn’s bilirubin level (to make sure that they are not going to need any intervention such as phototherapy), checking the newborn for PKU (a genetic disease that can affect the child’s mental development) and take care of any congenital abnormalities we find.  If a major abnormality is found these newborns are connected up with the pediatric specialty clinic which will follow them. 
 
As I listened to the newborn’s chest I heard a holosystolic murmur (murmur heard throughout all of systole) at her left lower sternal border.  We grade murmurs on the loudness of the murmur as well as how long they last through systole or diastole.  I graded the murmur as being a 3/6.  I didn’t pick anything else up on her physical exam.  But because she had a heart murmur I had to call the pediatric cardiology service.  They would have to bring their mobile echocardiogram machine with them (an ultrasound machine that bounces sound waves off of the organ being looked at, which is then picked up by the machine and reflected in pictures on the ultrasound screen). 
The little newborn probably had a VSD, or ventricular septal defect.  This is an opening in the septal wall between the patient’s two lower ventricles.  When patients have such defects their blood flow goes from their left ventricle to the right ventricle.  Having a VSD is the most common congenital heart defect that is found. 

Heart murmurs are graded on a scale of 1 to 6.  A 1 means that the murmur is barely heard with a stetoscope.  A 6 means that you can hear the murmur without a stetoscope.  Murmurs can be heard in systole (when the heart beats) or in diastole (when the heart is at rest).  If a murmur is heard in diastole this is generally thought of as being pathologic, i.e. a bad murmur.  If a murmur is heard in systole is can foreshadow something good or bad. 

Then we listen for the length of the murmur.  Does the murmur last for the length of systole or diastole?  Does the murmur only show up half way through systole?  In other words, when does the murmur show up and how long does it last?  This gives us some additional information on the murmur and where it might originate from. 

A few hours later the pediatric cardiology service showed up.  The cardiology fellow had the mobile echocardiogram machine with him.  The pediatric cardiology service liked to bring the mobile unit with them when assessing the newborns, seeing that they could acquire quite a bit of solid clinical information from it. 
I went in along with the cardiology fellow when she went into the nursery to see the newborn in question.  After listening to the newborn herself with her stetoscope, she agreed with me about the grade of the murmur and that it was holosystolic.  Then the cardiology fellow put some warmed gel on the transducer of the echocardiogram machine and put it on the newborn’s left chest and slowly moved it around.  As she did this, on her screen appeared the newborn’s heart.  On the bottom of the screen, the newborn’s electrocardiogram appeared (electrical activity of the heart). 
The echocardiogram showed the newborn’s atriums (upper chambers of the heart) were normal, as well as her aorta.  As the cardiology fellow moved the transducer down the newborn’s chest various views of her ventricles (lower chambers of the heart) came into view.  And there you could see a small opening between the two lower ventricles that was patent.  The blue color (showing blood moving away from the transducer) not only went up through the aortic valve (which is normal) but a small amount of it also moved off to the left, through the small septal defect and into the right ventricle.  So indeed the newborn had a ventricular septal defect.  Thankfully though it was on the smaller size, as defects go, so she probably would not need to have surgery.

With any of the cardiac congenital defects, many of them also have changes that are seen on the patient’s electrocardiogram, i.e. electrical activity of the heart.  Seeing that this little newborn only had a small defect in her septum separating her two lower ventricles, it wasn’t enough to bring about a change in her electrical activity in her heart.  Had she had a larger septal defect, changes in her electrical activity would have been seen. 
 
After the pediatric cardiology fellow finished with the echocardiogram, she wiped off the transducer gel from the newborn’s chest and walked out of the nursery to go find her mother on the post-partum OB floor.  The newborn would have to be followed in the pediatric cardiology clinic.  This little newborn would most likely do very well, and she had the potential of the septal defect closing on its own.  If it had been any larger she would have been facing some right sided heart damage as well as possibly some pulmonary damage.  Pediatric patients who have large septal defects usually end up with some sort of corrective open heart surgery to seal off the defect.       
The following morning the newborn was discharged with her mom home.  She had an appointment to be seen in the pediatric cardiology clinic in 6 weeks at which point in time she would have most likely have a full echocardiogram done. 

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