Electrocardiogram is an essential instrument nowadays not only in emergency rooms but also in ambulance cars or outpatient departments. It has multiple functions which give various information about the patient’s condition. Holter monitor is a type of ECG appliance. The difference between Holter monitor and conventional ECG is that it detects the patient’s heart function round the clock.
In my diploma theses I design and build such a Holter instrument I have reviewed the literature extensively which helped to understand how the heart works and the parameters of the ECG curve. Based on these I have prepared the detailed specification of the instrument. During specification, apart from the general capabilities of the system I describe the requirements set against each part.
After listing the requirements I have developed the whole circuit and schematic. I put the printed circuit into operation in line with schematic. The data collected during monitoring the patient is recorded on an external memory card by the readily made device. Evaluation of data was first performed offline with the help of Matlab. I have defined the place and size of QRS complex. I also demonstrate a method that is needed to detect ventricular fibrillation in this environment.
The instrument has a Bluetooth interface therefore it is possible to transmit data wirelessly. I have connected the device with an Android based smart phone via Bluetooth. The source code designed for Android is able to measure and show data as well as defines pulse rate nearly real time.