Medical Students Take iPod Sounds to Heart

PHILADEPLHIA, March 30 -- The iPod generation of medical students is swaying to the beat of mitral-valve regurgitation and aortic stenoses.

The sound of murmurs is music to the ears of these medical students who are being drilled in cardiac auscultation via downloadable MP3 files of beating hearts.

The training method draws on the power of repetition to teach abnormal heart sounds, said cardiologist Michael Barrett, M.D., of Temple University School of Medicine, in an interview.

For years, senior physicians have been murmuring about the failure of younger clinicians and physician wannabes to achieve the old-time sensitivity to the characteristic sounds of dysfunctional hearts.

Audio of heart sounds (mp3)

Normal heart sound:

Heart murmur:

Heart sound lesson:
In a study published in the American Journal of Medicine last year, Dr. Barrett (then at Drexel University College of Medicine, also in Philadelphia) and colleagues noted that in one study medical students correctly identified 12 cardiac events by their sounds only 20% of the time. Medical residents did slightly worse, with a 19% identification rate. Other studies of primary care physicians have shown only about a 40% proficiency in cardiac auscultation they noted.

"A lot of medical skills that we teach are intellectual skills, cognitive skills -- things you can learn by studying very hard in a book, and we teach auscultation as if it was a skill like that," Dr. Barrett said. "We gave a lecture, and I was the guy who gave that lecture for many years."

In the lectures, he would tell his students where the murmurs came from, and where they could best be heard through a stethoscope (e.g,, at the apex). He would then play a recording about 15 beats in length, after which he would reassure the students that they would be able to detect the abnormalities themselves during their rotations the next year.

"We actually looked at that issue and tested third-year students month-by-month-by-month, and their scores did not budge -- they stayed at 30%," Dr. Barrett said. "So I began looking into the idea that maybe auscultation isn't a natural skill, and in the literature I found evidence that the way a normal adult human learns to recognize a sound is by hearing it several hundred times."

In other words, learning to identify a distinct sound is a technical skill, like tying a shoe lace or a surgical knot, he said.

In the American Journal of Medicine study, Dr. Barrett and colleagues reported on a controlled trial in which 80 third-year medical students listened to an average of 500 repetitions each of six abnormal heart sounds: aortic stenosis, aortic regurgitation, mitral regurgitation, mitral stenosis and S3 and S4 gallops).

They gave the students digital sound files that had been burned onto CDs, but later learned that most of the students were converting them to MP3 files so that they could listen to them on their iPods or comparable players.

Controls did not receive the CD, but all participants performed cardiac auscultation on their patients as part of their routine clinical rotations, and all were tested within 30 days of completing the exercise by listening 10 heart sounds played for 20 seconds each.

The authors found that the digital files improved the students' proficiency at recognizing the sounds from a mean of 38.6% + 22.1% at baseline (as measured by a pre-test) to 88.9% + 16.0% after listing to the CD an average of 2.5 times.

In contrast, there was no change among controls, who had a pretest identification rate of 37.3% + 14.9% and post-test rate of 34.7% + 15% (difference for the intervention vs. control P

"This type of teaching lends itself so easily to the Internet that at Temple we've put all four classes of medical students on the Internet to learn this," he added/ "They go to a web site, we test them first, they download the files and listen as many times they need to, and then we test them again. It's very efficient from my point of view and it's very effective from theirs."