- Oral presentation
- Open Access
Multifractality of the heartbeat dynamics after beating heart myocardial revascularization
© Ksela et al; licensee BioMed Central Ltd. 2013
- Published: 11 September 2013
- Modulus Maximum
- Vagal Activity
- Multifractal Spectrum
- Singularity Spectrum
- Multivessel Coronary Artery Disease
Recent studies suggest that time series of healthy human interbeat intervals belong to a special class of bio-signals displaying multifractal properties. The breakdown of multifractality was observed in congestive heart failure and angina pectoris; however, there has been no attempt to evaluate multifractal behavior before and after beating heart myocardial revascularization (off-pump CABG).
Sixty consecutive patients with isolated multivessel coronary artery disease scheduled for off-pump CABG were included in the study. Twenty-four hour Holter recordings were performed preoperatively and on the seventh postoperative day. Multifractal properties of the RR data set were determined for both, day- (12:00h to 18:00h) and night-time (00:00h to 06:00h) periods of the ECG recordings containing at least 95% of pure sinus rhythm. Multifractal spectrum τ at q=3 (τ(q=3)), the peak position of the singularity spectrum (h_top) and the width of the singularity spectrum (Δh) were calculated by wavelet modulus maxima method as proposed by Ivanov et al. Mean differences over time were tested using paired-samples t-test. Results are reported as mean ± SE; p<0.05 or less was considered significant.
Preoperatively, τ(q=3) was -0.52±0.18 and -0.49±0.17, h_top 0.20±0.07 and 0.15±0.07 and Δh 0.31±0.14 and 0.71±0.14 for day-time and night-time period, respectively. Postoperatively, τ(q=3) was significantly higher for day-time period (-0.43±0.23, p=0.015), whereas h_top and Δh were significanly higher for both, day- and night-time periods (0.25±0.07, p<0.001 and 0.19±0.06, p=0.002 for h_top and 0.41±0.20 and 0.31±0.19 for Δh, respectively).
Significant postoperative increase of all multifractal parameters, except of τ(q=3) for night-time periods, clearly indicates that a marked breakdown of multifractal behavior into monofractal can be observed following off-pump CABG, indicating that multifractality is mostly governed by vagal activity.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.