With the appearance of fast 3G mobile phone networks and unlimited data plans offered by operators it becomes more feasible to use them for long term patient cardio monitoring. We developed a system that consists of digital electrocardiogram recorder, Windows Mobile smartphone and personal computer. ECG recorder is connected to the phone using cable or short range wireless link. Smartphone is connected to the Internet and forwards incoming ECG data to the PC with software for data processing. We performed several experiments to determine if it is possible to use this system for real time monitoring of patients electrocardiogram. In this paper we present results of these experiments and conclusions.