MedGadget points us to a service called EKGuard:

When a customer signs up for EKGuard, the company sends a handheld EKG monitor. They also take a customer’s medical history, contact his or her doctor and cardiologist, and explain how they should take a baseline EKG, for reference by cardiac specialists.

The portable monitor has three wires; placed in the right spots on the body, they record data from 12 different leads, like a standard hospital or ambulance EKG. When collected, the data build a picture of how efficiently electrical impulses are traveling through the heart. To transmit the EKG readings to the call center, the device translates the information into sound and plays it over a phone line to a computerized receiving station, where it is reconfigured into an EKG chart that can be analyzed for irregularities…

I wonder if they realize that a single, initial EKG is not the most accurate for myocardial ischemia:

The initial ECG is often not diagnostic in patients with ACS. In two series, for example, the initial ECG was not diagnostic in 45 percent and was normal in 20 percent of patients subsequently shown to have an acute MI. (via UptoDate)