Validation of a digitized Holter monitoring system by comparison with the Marquette case system.

Detection of silent myocardial ischaemia must be accurate and reliable. With the new digitized Holter monitoring systems these qualities are feasible. We tested one of these devices (Monitor One, Q Med) by comparison with a digitized and averaged ECG signal provided by the Marquette Case system during exercise tests in 30 patients with angiographically documented coronary artery disease. Detection and quantitation of ST segment depression episodes by the Holter system were excellent. Furthermore, indirect ECG criteria of ischaemia as R-wave amplitude variations were easily recognized. Thus digital monitors may be used to detect ischaemic events in prospective and multicentre studies for the diagnosis and prognosis of silent myocardial ischaemia.