Accuracy of the ambulatory ECG monitoring system Cardio-Data Mk4 in detecting exercise-induced myocardial ischaemia.

Abstract

The accuracy of ST-segment analysis in a direct-recording ambulatory ECG monitoring (AEGG) system (CardioData Mk 4 with recorder CardioData PR3) was compared with that obtained in a standard ECG recorder. Twenty two patients with coronary heart disease and a positive exercise test were submitted to a second bicycle exercise test with concomitant AECG monitoring. Application of a junction box made it possible to record the two bipolar AECG leads simultaneously on both standard ECG (leads ECG 1 and 2) and AECG (leads 1 and 2). We determined the time of the beginning, end and maximum and the magnitude of the ST-segment depression in bipolar leads AECG 1 and 2, and ECG 1 and 2. AECG monitoring was just as accurate as standard ECG: time intervals between the different leads showed good alignment. The degree of maximum ST-segment depression in ECG 1 (mean +/- SD: 0.22 +/- 0.11 mV) was identical to that in AECG 1 (0.22 +/- 0.13 mV). Maximum extent of ST-segment depression was lower in ECG 2 and AECG 2 but also comparable (ECG 2: 0.13 +/- 0.14 mV, AECG 2: 0.15 +/- 0.17 mV). Thus, ST-segment depressions found with a standard ECG recorder can also be reliably detected with a direct recording AECG monitoring system.