I recently saw Eric Topol, MD demonstrate this and so... he guided me to get this absolutely neat and useful device. The AliveCor Heart Monitor is a class II medical device (just approved by the FDA) which snaps onto the iPhone 4 or 4S as a case and then wirelessly communicates with an app on the iPhone. The Heart Monitor does not use power from the iPhone, but utilizes a 3.0V coin cell battery that will take up to 12,000, 30-second ECGs before needing replacement. The Heart Monitor also uses AliveCor's proprietary wireless communication protocol to communicate with the app. There is no pairing required between the iPhone and the heart monitor.
To generate a Lead I ECG, rest the electrodes on the fingers from each hand (iPhone Home button should be on the right). The app senses skin contact on the sensors and when an acceptable connection is made it counts down to initiate the ECG recording. Set your app to take 30 second, and up to continuous, rhythm strips. While the ECG records it will also display heart rate. ECGs over 10 seconds are automatically saved in the app for review and can be annotated with details or can be discarded. ECGs can be inverted if needed and gain and "paper" speed adjusted as well. On the iPhone you can create the ECG's as PDF's and analyze and print them.
The app is free on the Apple APP store as "AliveECG". The case is available on the website http://www.alivecor.com to licensed physicians for $199 (US).
Should you want to, the ECG's are stored on the AliveCor.com website and the access is secure and HIPAA-compliant. Protected health information (that is the EKG's and any identifiable information) are encrypted in transit. You can access the ECG data later if needed.
I've used it with some patients who were anxious about their heart. I was able to create the PDF and then attach it into our EKG section of our EMR*. Additionally, it has helped me with some atrial fibrillation patients who seemed to have a regular rhythm but when I used the AliveCor Heart Monitor, the patient and I found them to be in a well controlled atrial fib. Of course, the 'neat factor' does impress the patients but it also engages them and helps them understand their heart rhythm more. As my partners and I use it more, I am sure we'll find it to be a handy tool both in and out of the office and hospital.
UPDATE (2015): Another version with a detachable monitor is now also available from AliveCOR
A video on how it works: https://www.youtube.com/watch?v=-HUhnGBdQdY
and another https://www.youtube.com/watch?v=0pE_InOy1mk
These videos show the older models with software/app improvements to filter out interference. And now ...there is a APPLE WATCH VERSION!
*We use iFile Explorer Pro to take the PDF on the iPhone and wirelessly import it an place in the EMR section of the EMR.