Quantitation of exercise electrocardiography.

EXERCISE TESTING is an established method for detecting coronary artery disease, evaluating the severity of disease and prognosis in patients with coronary artery disease and assessing the effect of therapy. The ECG responses can be used as an indicator of exercise-induced myocardial ischemial in context with the patient's history and othler data obtained during exercise (table 1). The diagnostic value of exercise electrocardiography may be enhanced by computer-assisted quantitative analysis of the ECG2-8 (table 2). This improvement is due in part to a reduction of the noise level and to application of special criteria, such as a combination of ST amplitude and ST slope.2 S Various systems have been designed for computer processing of exercise ECGs. These systems generally aim at better measurements through improvement of the signal-tonoise ratio in the ECG recorded during physical exercise, more accurate diagnostic classification of the exercise ECG and reduction in the total time involved in the execution and reporting of the test. Details of the various systems have been described.7 The first programs were developed and implemented on medium-size computers or minicomputers. Application of these programs remained restricted to the hospitals where they were designed. In recent years, microprocessor-based systems have been introduced comtnercially.7 8 This commercial availability has created a new situation. The user of a system developed in the same hospital is usually aware of the strengths and the limitations of that system. However, the clinician who buys a system from a manufacturer has, at best, an incomplete understanding of the hardware and software provided. This may lead to errors, especially if