June 4, 2001 -- Remember visiting the school nurse for eye exams or hearing checks? Well, an experimental technology now being developed may someday make it possible for the school nurse to screen for heart defects.
The concept, says Curt G. DeGroff, MD, is to combine an electronic stethoscope with a computerized ear so that the nurse could actually screen for heart murmurs. DeGroff tells WebMD that about three-quarters of children had a heart murmur at one time or another and most of these murmurs are "innocent, meaning that they don't signal any structural problem with the heart, while a smaller number are associated with heart defects."
DeGroff and bioengineers at the University of Colorado Health Sciences Center and Children's Hospital in Denver are trying to train a computerized ear called an artificial neural network, or ANN, to differentiate between the innocent or benign murmurs and more serious ones.
They describe their initial experiments in a study published in Circulation: Journal of the American Heart Association.
DeGroff says that he and his colleagues recorded heart sounds from 62 patients, 37 with concerning heart murmurs and 32 with innocent murmurs. Those recordings were then translated into digital signals and fed into the computer-based ANN to train it by repeating the sounds again and again "the same way a doctor is trained." He says that in this very early test the ANN was able to accurately identify the serious and innocent murmurs.
DeGroff says that his team is now working to record many more heart sounds to increase the range of the device and make it even more accurate. He says this tool will never replace a skilled doctor but it may reduce the number of unnecessary referrals.
Pediatric cardiologists tell WebMD that the experimental device is intriguing but add that fitting a new device into the diagnosis of heart murmur may not be that easy. Catherine L. Webb, MD, associate professor of pediatrics at Northwestern University Medical School in Chicago, tells WebMD that "I think everyone is looking for the perfect screening device and this is a good effort" but "it still needs a lot of work."
Webb, who is an attending cardiologist at Children's Memorial Hospital in Chicago, says one problem is the emotionally charged atmosphere that surrounds a diagnosis of heart murmur. "When you tell parents that their child has a murmur, they freak," says Webb. For that reason she thinks that the diagnosis should be delivered by a skilled cardiologist who can carefully explain the difference between innocent murmurs and significant murmurs.
Philip Smith, MD, clinical director of the heart center at Akron Children's Medical Center in Ohio agrees with Webb. Smith tells WebMD that the great majority of murmurs are innocent, and "very few indicate a structural problem in the heart."
But it is difficult to make parents understand that very significant difference. "Moreover even when a murmur does suggest a structure problem, most of these problems can be taken care of very effectively with surgery or interventional devices." Smith says that he recalls "when I was in eighth grade I had a classmate who was very sick because he had a hole in his heart. Everyone knew this and everyone knew that poor Ralph probably wouldn't live long. But modern surgery has changed all of that."
Webb says, too, that no matter how well the ANN is "trained" it is still likely to make some mistakes in diagnosis. She says that even skilled cardiologists run this risk. For example, "I had three heart murmurs today in clinic. In one, I was convinced that child had a hole in his heart so I ordered an ultrasound -- it turned out the murmur was innocent."