The stethoscope, the 200-year-old accessory without which no doctor is complete, could soon be replaced by the humdrum mobile phone.
A computer scientist who wrote a program that turns an Apple iPhone into a stethoscope has made a major advance in medical technology and created a sensation among heart specialists. The application, called iStethoscope, was developed as a "bit of fun", and has become a runaway success after being downloaded millions of times by users across the world.
Cardiologists say the software has saved lives and brought specialist expertise within reach of patients in remote parts of the world. Heart sounds can be recorded and emailed to doctors anywhere for an expert opinion.
Peter Bentley, a researcher who developed the application in the computer science department at University College, London, said he was amazed by the response.
"The idea began as an experiment," he added. "I had a new, popular science book out last year and I wanted to see if I could tell people about the book using a free iPhone application that did something useful.
"It was intended as a fun toy but to my astonishment it was downloaded by several million people all over the world in the first six months. Then I started receiving emails, phone calls and visits from cardiologists all over the world. They said it worked better than commercially available digital stethoscopes. They were tremendously excited. One flew over from the US just to discuss it with me."
The cause of the doctors' excitement was that the audio quality from the iPhone was far superior to that from digital stethoscopes. Mobile phones are a huge market compared with digital stethoscopes, and economies of scale mean they are made with better hardware.
Responding to requests from specialists, Mr Bentley extended the application to allow heart sounds to be recorded, emailed and analysed. The application costs 59p to download, but cardiologists say it does a better job than equipment costing thousands of times as much.
Glenn Nordehn, a US cardiologist researcher and specialist in digital stechoscopes at the University of Minnesota, said: "This is the best thing to come around in terms of medical equipment for a very long time. [His] closest competitor charges about 3,000 times as much"
Mr Bentley is now working on further iPhone applications, such as an electrocardiogram reader. "This is the way everyone wants to go," he said.