Two Low-Cost Solutions for Cardiac Mobile Monitoring

A small device, named WalkECG, developed for out-of-hospital cardiac monitoring, is presented. Two models were developed, one including an embedded GSM/GPRS modem and a second model which is able to set a Bluetooth connection with a mobile phone. The device is based on the MSP430F1611 microcontroller and includes a two-channel ECG amplifier, a graphic LCD, a keypad, a GSM/GPRS embedded modem (or a Bluetooth module depending the model) and a battery. The heart rate, the ST segment deviation and the premature ventricular beats rate are computed; 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 twelve ECGs from MIT-BIH database. Never a ventricular beat was classified as normal and 98,05% of QRS complexes were detected. Also, the device was tested with volunteers and never an ECG strip was trnasmitted in a normal condition of the studied person. When the communication process was tested, a remarkable difference between the transmitting and receiving signals was not observed in a graphical comparison sample by sample.