engleski

Microvoltage Variability Of Isoelectric Segments In High Resolution 3-Axial ECG Recording Of Healthy Volunteers: Age & Gender Characteristics

Purpose: This study was based on a theoretic model of heart electric activity (Kurbel S. Theor Biol Med Model. 2014 ; 11:10.). The aim was to determine whether variability of the high resolution three axially recorded isoelectric segments (P-R, S-T and T-P) in successive cardiac cycles show some age or gender specific features. Subjects: 27 younger (mean age 21 years) and 27 older volunteers (mean age 53 years). Methods: Three-axial high-resolution ECG (1 kHz sampling rate) of healthy subjects during 200 seconds, recorded by Biopac Students Lab. Eight isoelectric segments of 50 ms duration were than extracted due to their position from the R wave peak (one P-R, two S-T and 5 T-P segments). Fourier analysis was done: A/ Fourier of distances in mV between each XYZ point and the center of that segment ; B/ Fourier of distances in millivolts between successive milliseconds, in mV/ms. Results: Method A: Gender and age specific differences were found. Women showed smaller harmonic powers during systole and protodiastole, while higher harmonics were stronger in telediastole. Older persons showed higher harmonics during telediastole. Method B: Age dependent differences were found in all eight isoelectric segments, especially during diastolic filling. No gender specific differences suggests that this variability was purely age dependent. Conclusions: These results fits well the initial theoretic model the heart electric activity can be described as unbalanced transitions between stable configurations of the heart electric field during P-R, S-T & T-P segments.

high resolution ECG; izoelectric segments; microvoltage variability

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