Detection of very high frequency magnetocardiographic signals within the QRS complex using discrete Daubechies wavelet transformation

The frequency domain analysis of cardiac signals is an important tool for arrhythmia rise prediction. The commonly used Butterworth filter leads to artefacts because of oscillating and phase response and is therefore not suitable for the analysis of high frequency components within the QRS complex. We applied discrete Daubechies wavelet transformation in the detection of very high frequency magnetocardiographic signals within the QRS complex. Four study groups (anterior and posterior myocardial infarction, dilated cardiomyopathy, normals) were analyzed. In all patients and normals high frequency components of about 200 Hz were present within the QRS complex. Different pattern occurred between and within the groups. Daubechies wavelet transformation is an appropriate tool for time-frequency domain analysis of magnetocardiographic signals