WalkECG: a mobile cardiac care device

A small device, named WalkECG, developed for out of hospital patient monitoring is presented. This device is based on the MSP430F149 microcontroller and includes a two-channel ECG amplifier, a graphic LCD, a keypad, a GSM modem and a battery. The heart rate, the ST segment deviation and the premature ventricular beats rate are computed and a normality limit is set for each one. When one of these limits is reached, an ECG strip is transmitted to a Telemedicine Central Station (TCS) and the device waits to display the receiving answer. The methods used to analyze the ECG were tested with real ECGs and all the QRS complexes were detected. Never a ventricular beat was classified as normal and 97.67% of normal complexes were well classified. When the communication process was tested, a remarkable difference between the transmitting and receiving signals was not observed