Coded within the sounds made by the functioning heart is a wealth of diagnostic information. However, even to the best trained medical ear, these sounds are quiet and sometimes difficult or even impossible to perceive. When considering symptoms, one might think that the louder the sound the more significant the condition. This might be true with your failing car transmission or aging refrigerator but not always the case with your heart. Many critical sound symptoms are on the verge of perception and are easy to miss.

Clinical use of heart sounds has a very long history. Over time stethoscopes evolved to include the “bell” and “diaphragm” listening surfaces. Each aided differently in improving the audibility of difficult to perceive sounds. Modern digital stethoscopes essentially copy the sound filters of traditional stethoscopes.

One of the early things we did at Sparrow was to use spectral sound analysis to create a filter that greatly facilitates the perception of very quiet but important symptoms. In the process we removed the need for clinicians to have to switch between traditional filters to hunt for sounds. We call our filter a “Cinema filter” because it focuses attention on the most important things, making them clear and contrasted so you can pick out the nuances of the underlying story – kind of like going to a good movie.