An optimal automatic beat detection algorithm based on detector switching

In this paper we present an innovative approach to improve the performance of beat detection in the presence of a significant level of noise on some ECG leads in a setting of multi-lead acquisition. The idea is to run simultaneously two detectors (ldquoprincipalrdquo and ldquosparerdquo) and to dynamically switch between them according to the level of noise on the leads used by the detectors. First, default independent leads are assigned to the detectors; then, a bootstrap phase is necessary during which average QRS amplitudes are established for all leads. Based on the independence of the leads and the QRS amplitudes best leads are automatically computed and assigned to the detectors. After the bootstrap phase, the algorithm calculates the noise level of the leads used by both detectors every 500 ms and switches to the spare detector if the noise in the principal detector leads exceeds a threshold (T). The performance of the algorithm was tested on a database created for the purpose; the database contains 101 1-hour 12-lead Holter records selected from 24-hour recordings with a commercial analysis system on the basis of the amount of artifact. The performance of the algorithm was tested for various values of T and noise observation windows. A QRS sensitivity of 99.7 %, a QRS positive predictive value of 99.3 %, a ventricular sensitivity of 91.0 % and a ventricular positive predictive value of 55.3 % have been achieved.