Computer-aided visual analysis of long-term ECG recordings

In Sweden, long-term ECG (LECG) recordings are predominantly used to evaluate whether symptoms such as palpitations, dizziness and syncope are caused by cardiac arrhythmias. The analysis of LECG for this purpose differs considerably from the analysis of LECG recorded to demonstrate ventricular arrhythmias in post-infarction patients. A computer method was developed with the primary goal of assisting in the analysis of the former type of LECG. The computer searches the recording for episodes of arrhythmia and presents comprehensive graphical information about, for example, heart rate and significant arrhythmias. During analysis, the operator selects any computer-indicated episode and/or period in which the patient experienced symptoms. The selected ECG segment is presented instantaneously on a screen and/or a recorder. Thus the main emphasis is on the facilitation, rather than the replacement, of visual analysis. The ECG is displayed in various modes. Continuous segments can be inspected at 20 or 60 times real speed. Computer-indicated episodes of particular types of arrhythmia can be displayed episode by episode. This allows extremely fast inspection of, for example, all episodes with abnormally long R-R intervals. A cheap, permanent record of any episode, marked with patient identity and time, is easily produced on an ECG recorder