Effect of acute myocardial ischemia on different high-frequency bandwidths and temporal regions of the QRS

Abstract

The purpose of this study was to describe the changes in high-frequency QRS (HF-QRS) components due to myocardial ischemia provoked by prolonged artery occlusion during percutaneous coronary interventions (PCI). Signalaveraged ECGs from 69 patients were obtained during PCI procedures and comparison of high-frequency components of the QRS at different temporal regions and frequency bandwidth were performed. Continuous wavelet transform was applied to estimate the energy contents over the studied timefrequency regions. Seven frequency bands from 50 to 300 Hz, with bandwidth = 100 Hz were considered. The sum of all 12 leads energy decreased significantly (p < 0.001) from pre-PCI to PCI during both second half and total QRS complex in all frequency bands, but the main effect was found in the 200-300 Hz band. The energy changes were more marked toward higher frequency bands. The second half of QRS complex was more sensitive to changes due to myocardial ischemia.