Cardiovascular or heart disease can be prevented and may be detected early. Heart condition examination can be conducted in various ways, one of them is through electrocardiograph examination (ECG). The ECG is not only used in hospital, but also in all health service. In this research, diagnostic tool and heart condition monitoring was designed based on real-time heart electricity with compact size, and also easy to use. The designed ECG used Raspberry pi as the microprocessor and the Qt Creator application is used to process the record visualization and acts as the media to store the ECG data. The testing and measurement methodology used is by comparing the value of heartrate, amplitude, and pulse width in ECG module with ECG calibrator tool (Fluke PS410 ECG Simulator). The error rate on real-time heart rate was 0.20% and with the stored file at 1.11%. The error rate on ECG signal amplitude was 0.77% and the pulse width was 0%. Based on the testing on ECG module, the heart rate and ECG signal recording result can could be conducted and resembled to the standard ECG signal