Attenuation of QRS Power in the Frequency Range from 0.05 to 1 kHz

Abstract

The high-frequency QRS (HFQRS) signal was analyzed in four groups of subjects: healthy, patients suffering from coronary artery disease, heart transplanted patients and patients with left bundle branch block (LBBB). Subjects were measured in the supine position with a high-quality ECG system (fs=5 kHz, ADC 24 bits). The dependency of HFQRS power, maximal amplitude and HFQRS width on the passband used was analyzed. Results: The dependency between HFQRS power and frequency in logarithmic scales is nearly linear across all groups. Significant differences exist in HFQRS power attenuation in regard to frequency between groups of subjects, P<0.001. This attenuation is maximal in healthy subjects-48.1±3.7 [dB per decade], minimal in LBBB-40.2±2.7. Based on significant differences between healthy and patient groups, we assume that QRS power attenuation may represent new information in ECG analysis. This parameter is independent of the choice of the analyzed frequency band. The dependency of HFQRS shape on frequency is presented by analysis of a healthy subject. Explanation of this significant dependency is a task for the future.