Detection of acute ischemia episodes from QRS angles changes using a Laplacian noise model

Ischemia detectors represent a useful diagnosis tool to identify acute ischemic episodes in coronary artery disease patients. In this paper, a detector of acute ischemic events based on the analysis of the QRS angles is presented. This acute ischemia detector has been developed by modelling the ischemia-induced changes in the QRS angles as an abrupt change with a certain transition time, assuming a Laplacian noise-model. The standard 12-lead electrocardiogram was used to test the proposed detector. For such proposal, we analyzed 79 patients undergoing a PCI procedure during about 5-min occlusion duration in one of the major coronary artery (LAD=25, RCA=38 and LCX=16). The three detector at the groups of patients presented good outcomes in terms of sensitivity and specificity achieving up to Se=72.7%, Sp=95.5% in the LAD group, Se=75.2%, Sp=97.2% in the RCA group and Se=72.2%, Sp=100%. in the LCX group. We conclude that the QRS angles can be used as a trigger for detecting acute myocardial ischemia although this must be further validated with other contexts in which ischemic events occur more gradually.