Background

The links below provided us with some background on wearable heart monitors and using Arduino boards to read through a heart rate.

This article talks about text-to-911. The ability to contact 911 through text is expected to be in widespread use in the near future. This inspired us to connect our device to a smartphone through Bluetooth. We want to eventually program the device to send texts to emergency services.

http://www.fcc.gov/text-to-911

We used this as a guide to get get the Arduino to communicate with a smartphone through Bluetooth connection.

http://www.instructables.com/id/Android-talks-to-Arduino/

None of our team members have any background in human biology or biomedical devices. This served as a source to learn how to read an ECG signal. Our code for detecting heart rate irregularities was based on this information.

http://a-fib.com/treatments-for-atrial-fibrillation/diagnostic-testing/the-ekg-signal/

Heart rate abnormalities can be seen in an ECG reading in many different ways. Our device detects irregularities in the time between "peaks", or the QRS complexes. This was based on the information found here about sporadic QRS complexes can be indicative of an arrhythmia.
http://www.ncbi.nlm.nih.gov/books/NBK2214/

This is the manual for the ECG shield we used. The shield also came with sample code for detecting an ECG signal. 

https://drive.google.com/file/d/0B3sMYj_MAeb0RUE1bjlZZXlTOEU/edit?usp=sharing