A new tool for heart disease prognosis in the community

The aim of this paper is to discuss the main characteristics of a system created to study, in a community, the evolution of people suffering cardiac disease or people prone to suffer it. The system has two main components: a portable device for ECG acquisition, henceforth Recorder, and Windows-compatible software, named Analyzer, to storage and study the signals acquired by the recorders. The Register acquires the twelve leads of the standard electrocardiogram (ECG) simultaneously. These signals and the mean heart rate are displayed on the device screen. When the operator requests, the Recorder measures the amplitude and duration of all ECG waves and other relevant electrocardiographic event. All the information is stored on the Recorder; this data is then transmitted, via USB, to a personal computer running the Analyzer. The received information is stored in a SQL database and the trend of the following ECG parameters is computed for each patient: spatial dispersion of QT interval is studied to predict dangerous arrhythmias; the Sokolow Index is analyzed due to its relationship with ventricular dilatation and hypertrophy. Also, the progression of R wave amplitude in chest leads is studied in patients who have suffered a heart attack. The Recorders are able to connect to a Telecardiology system, developed by the authors, in order to ask for advice in a sudden urgency. Five prototype Recorders have been manufactured and evaluated successfully according to the IEC 60601-2-51 standard. The CSE database was used to test the ECG processing algorithms. The average error in the measurements of the QT interval length was 7,62 milliseconds; all the mean errors in measurements of the ECG waves met the tolerances described in the IEC 60601-2-51 standard.