Free to the World: Cobb's $30 heart sound monitor

Okay, here's a nice way to combine some simple tech items to get high value results at a low cost.

The Challenge: Doctors need a way to listen to the heart beat of patients who are experiencing episodes of irregular heart beat. Past technology has focused on recording heart beat for extended periods of time hoping to catch the episode, useful for some things, but not this intermittent, periodic problem. Plus they are costly and inconvenient to use.

The Solution: Provide patients with a small and convenient device that records heart beat on demand in a format that is easy to transmit to the doctor.

Background: A few years ago my heart started beating funny, not all the time, just sometimes. No, let me re-phrase that: A few years ago, this friend I have, his heart started to beat funny (you never know when the insurance companies will start spidering blogs for evidence of health conditions that could justify even higher premiums).

This friend went to a cardiologist whose nurse wired him [my friend] into a harness that listened to his heart and was supposed to fit under his shirt (like the kind of 'wire' you might see in a crime caper comedy). After 24 uncomfortable hours my friend reported back and a reading was taken from the listening device. But not much showed up and my friend was finding it hard to time his visits to the doctor with the odd heart beat.

So I invented a cheap portable patient-operated heart sound reporting system. I bought a $30 Wombsong foetal monitor at Walmart, the kind you use to listen to your baby before it is born. Then I connected an audio recorder via the monitor's headphone output socket.

When my friend felt his heart beating 'funny' he could lay this thing on his chest and record the sound. This setup could record the sound digitally, with an iPod, a Treo, or any number of digital recorders, so this friend could then, theoretically, email the file to his cardiologist (if his cardiologist would only read his email).

In Practice: It worked like this. We recorded an episode on a pocket tape recorder then transferred that to the computer, reduced the background noise with Gold Wave (a terrific shareware audio editor) and saved it as an mp3. At his next visit with his cardiologist my friend pulled out his Treo and played the recording to a very impressed doctor. Much medical enlightenment was gained.

Of course, he could also have blogged the recording like this (click arrow to play, or click the song title to play in your default player):

Heartbeat recorded on $30 device

Now, after that fleeting moment in which I dreamed of a multi-million dollar IPO of Cobb's Cool Cardio Kit [NASDAQ: CCCK] the right thing to do reared its beautiful head: share this with the world for free. Now anyone with $30 and a little bit of tech-savvy (or a friend thus endowed) can take the sound of their heart to the doctor. Hopefully some lives can be saved, as well as a lot of money better spent on other things.

But woe betide anyone who seeks to cash in on this invention, with the possible exception of the people who already make the foetal monitors and can easily re-purpose them for this (add the instructions for recording to an iPod or rework design to include an mp3 recorder and/or USB connection and/or removable flash storage).

Tech Notes:

Recording--direct to digital makes a lot of sense but a lot of digital recorders don't record to mp3 (I have used Sony and Panasonic devices that record in their own formats) and this means you often have to do some sort of conversion so that the file is in a format accessible to the doctor or the playback device. Dumping the recording to a PC/Mac app like GoldWave makes conversion easy and allows clean-up. GoldWave has this great filter that lets you select a 'silent' section and filter based on that, in other words, a moment of space between explicit sounds will show the background noise and that can be filtered out in one step. , or play the sound back from the recording device, which is easy enough to do with an iPod or Treo).

Foetal monitor--is used for the recording because it is already designed to make internal body sounds audible. There is no great rick to this, just a properly tuned pickup at the narrow end of a cone-shaped, sound-focusing opening on the bottom surface of the unit that lays on the patient's body (over the heart when used in this invention). I used a WombSong, so named because it also allows you to play music to your unborn child (a scary notion given the musical tastes of some parents). These are now available for quite a bit less than $30 and since you can get a cheapr recorder for about $10, you can still make the whole thing for around $30.

Note that this is NOT your fancy "medical quality" foetal monitoring unit. It does not need to be. Check the recording above and you will hear that this is exactly what the cardiologist needed to hear, and would probably not have heard if "my friend" had not recorded it.

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