Higher Frequencies in QRS Complex for the Detection of Myocardial Ischemia

Several studies investigating the high frequency QRS (HF-QRS) behavior have reported the superiority of the HF-QRS method compared to the standard ST-segment changes in acute coronary syndrome and ischemic heart disease (IHD). The potential diagnostic contribution of five selected parameters was tested in three frequency ranges - HFQRS (150-250Hz), VHFQRS (250-500Hz) and UHFQRS (500-1000Hz) in healthy subjects and IHD patients. Significant differences were found between healthy and IHD subjects in all tested parameters and analyzed passbands. All parameters have comparable diagnostic contribution with minimal or no effect of the different frequency ranges. Despite significant differences between the groups, the parameters evince very large inter-individual variation that limits the clinical usefulness of the parameters to discriminate between healthy subjects and IHD patients. The implementation of a heart rhythm excitation would allow analyzing the changes of the parameters during increased oxygen demand of myocardium.