# Design of an Open Remote Electrocardiogram (ECG) Service
## 1 Introduction  
In 2017, the REHEARSE-AF study [1] investigated the efficacy of electrocardiogram (ECG) screening in a home _health-care_ style asking 500 patients to record without assistance a 3-leads ECG. The measurement was run two times a week for the period of one year using commercial devices. Each record was uploaded to a server, using a WiFi Access Point (AP) available in the patient's home. The ECG was automatically screened to detect Atrial Fibrillation (AF) symptoms, and later over-read by a specialist. The outcome of the study was encouraging, since the likelihood of early AF diagnosis, compared with that of a routine care arm, was significantly increased, at a price of little more than 10,000$ per diagnosis.  
There are many other use cases for a remote ECG service, besides the relevant one described above: two stories may give an idea. One is that of an ambulance with paramedical personnel rescuing an injured person after a car accident. It is likely that the Internet is reachable using ground or satellite broadband services, possibly tethering a smartphone. Using the online remote ECG service, we deliver the trace to the medical staff in the hospital, which defines the emergency level. A different home health-care story is that of a cardiac patient that is periodically contacted by her family doctor to check general conditions. In that case, the physicist uses the remote ECG service to receive the trace without leaving his desk, possibly on the phone with the patient.  
Remote ECG services have long been recognized as relevant, and have been the target of research interest and investments. There are currently many pilot initiatives going in that direction--similar tothe one referenced above--that are supported by public and private funding, but it is hard to scale up such experiments to cover a whole community, instead of a sample. The concern is not about their proved effectiveness, but about their financial impact.  
The hardware and the infrastructure that acquires and manages the trace, which we call the _remote ECG service_, have a significant cost. This was justified twenty years ago when such services emerged, but it is not consistent anymore, given the fall in prices of high-tech devices and services. Exploring today the feasibility of a low-cost, open remote ECG service may break the status quo, and raise the interest of stakeholders--i.e., those that produce, manage or use medical equipment--towards technologies and design options that make affordable a widespread service made of inter-operable devices and networks.  
This paper goes in that direction and proves that an open, low-cost service for long-range delivery of a 3-leads ECG is within reach: we show how to implement it using cloud facilities integrated with personal devices. The market offers comparable solutions, like those used in the REHEARSE-AF study, but these rely on proprietary hardware, protocols, software and services. This state of affairs biases high prices, and ultimately limits such lifesaver services to diseases that are sufficiently diffused to promise a reasonable _cost per diagnosis_.  
A feature of this project is that its results are reproducible and, if brought to production, they may be useful for large scale screenings to obtain results comparable to those described for the REHEARSE-AE project, but at a significantly lower cost.  
The paper is organized as follows:  
* the next section is a review of on-topic literature that introduces our methods and results;
* Section 3 applies defined methods in the design of a remote ECG service;
* in Section 4, we describe the materials to implement a functional prototype
* in Section 5, we perform a exhaustive test of all components, to assess the results and guide future improvements;
* finally, we discuss the potential of our prototype in some use cases.