ECG Acquisition in a Computer - ECG Acquisition and Automated Remote Processing - page 75

Real-time monitoring of cardiac patient applications are divided into two major
areas, viz., ambulatory monitoring for chronic patients and home telecare systems.
For emergency medical service, ECG transmission of the patients from ambulances
was practiced from early 1970s. In [ 10 ], a low-cost mobile unit installed in an
ambulance is described, which uses communication equipment for simultaneous
voice and ECG transmission between the emergency vehicle and nearby hospital.
Accordingly, prehospital emergency arrangements could be achieved, and hence,
some critical patients with arrhythmia could be saved. A similar study is carried out
in [ 11 ] for acute myocardial infarction (MI) patients. An offline compression tech-
nique of 12-lead ECG is reported in [ 12 ], where a portable ECG machine was used for
acquiring the ECG data and transmitting through a cellular phone.
Mobile tele-cardiology was also successfully implemented using satellite
communication in airborne aircraft and mid-ocean ships to handle an emergency
situation arising due to sudden cardiac pain of a passenger. In [ 13 ], the authors
report functional description and successful implementation of a mobile satellite
communication (MSC) for telemedicine services with 3-lead ECG signal and some
other vital signs being transmitted along with the voice signals for a real-time
consultation with the base station cardiologist, located at a city hospital. The main
challenges of MSC are channel capacity (10-100 kbps) to allow multiplexed
transmission of data and video signal, data reliability, delay of transmission (which
is sometimes 1 s or more) and electromagnetic interference with the navigation
system of the moving vehicle itself. With the increasing practice of ECG
transmission for various medical services, standard communication protocol
(SCP)-ECG was developed in Europe in 1993. The SCP-ECG standard specifies the
content and the structure of the information between the transmitting station
(mobile cart) and the receiving station (host) for computer-assisted electrocardi-
ography. In [ 14 ], an implementation of the protocol for real-time digital trans-
mission of the 12-lead ECG at a speed of 9,600 bps from ambulance car to the
nearest hospital is reported. The major challenges faced were time delay (some-
times 2 min) for the initial establishment of the telephone connection and moving/
static condition of the vehicle. It was found that the rate of correct reception of the
ECG is better when the vehicle is at rest. Similar systems reported [ 15 , 16 ] were of
store and forward type, which means, they cannot be used for real-time monitoring
applications. In [ 17 ] the authors report a GSM-based real-time system for the
transmission of critical biosignals and images from a mobile unit to a dedicated
workstation, named 'telemedicine consultation station' acting as the consultation
site. The mobile unit collects 12-lead ECG (sampled at 200 sps), SpO 2 , heart rate,
blood pressure, temperature, images (at 320 9 240 pixel resolution) and commu-
nicated through TCP/IP over GSM at 9.6 kbps. The patient data collected at the
workstation are archived at an encrypted database management system for future
use. The developed system showed good response with occasional interruption in
case of ECG and Sp0 2 transmission. The medical expert could advice the paramedic
personnel from the consulting site during the patient being transported to hospital.
Another significant development took place in the area of using internet ser-
vices

for remote patient care. This allowed elderly patients to contact the