I have no direct experience with any of the systems you mention.
Just to be helpful here are some clarifying questions...
Will the device be plugged into a patient continually? It will need to be compact.
Or will the patient plug the device into an existing embedded heart monitor/pacemaker? Can you be sure the patient will be in a condition to do this during a crisis?
Will it be battery powered? What type of batteries? How will you ensure they're kept charged?
What will trigger making a call to the hospital? Will the patient have to press buttons, dial a central number, etc.? Or will your device automatically be able to detect unusual heartbeat signals?
Which heart data do you intend to transmit? Numbers only (rate, strength, regularity, etc.), or a continuous analog signal of the heart beating?
Are you knowledgeable as to how to intercept data coming from a manufactured GPS device? Or do you intend to build your own?
Are you able to rework the GPS data in order to send it to the hospital in form they can read?
Does the hospital have an existing receiving system with which your device needs to be compatible?
Will data be conveyed as audio tones (dual-tone multi-frequency signaling, aka Touch-Tone)? If so then you can build your prototype around a cellphone.
Will the hospital send back any signal? To acknowledge data received? To transmit instructions for the patient? Etc.
How frequently do you intend to transmit patient's location? Every ten seconds? Sixty seconds? Presumably you are able to program the device to send GPS data alternating with heart data (or heartbeat signals).
To do this all on one board, one will need to be accomplished in a number of fields, including:
* radio transmission and reception
* cell communications
* medical-related logistics
* data acquisition and transmission
* Battery maintenance
Etc.