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<str<strong>on</strong>g>European</str<strong>on</strong>g> <str<strong>on</strong>g>C<strong>on</strong>ference</str<strong>on</strong>g> <strong>on</strong> Ma<str<strong>on</strong>g>th</str<strong>on</strong>g>ematical and Theoretical Biology 2011<br />
[3] G. Bub, A. Shrier, and L. Glass, Global Organizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Dynamics in Oscillatory Heterogeneous<br />
Excitable Media. Phys. Rev. Lett. 94 028105-1 – 028105-4.<br />
[4] D. Makowiec, Modeling <str<strong>on</strong>g>of</str<strong>on</strong>g> intercellular c<strong>on</strong>necti<strong>on</strong> in <str<strong>on</strong>g>th</str<strong>on</strong>g>e sinoatrial node Acta Physica Pol<strong>on</strong>ica<br />
<str<strong>on</strong>g>European</str<strong>on</strong>g> <str<strong>on</strong>g>C<strong>on</strong>ference</str<strong>on</strong>g> <strong>on</strong> Ma<str<strong>on</strong>g>th</str<strong>on</strong>g>ematical and Theoretical Biology 2011 [3] G. Bub, A. Shrier, and L. Glass, Global Organizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> Dynamics in Oscillatory Heterogeneous Excitable Media. Phys. Rev. Lett. 94 028105-1 – 028105-4. [4] D. Makowiec, Modeling <str<strong>on</strong>g>of</str<strong>on</strong>g> intercellular c<strong>on</strong>necti<strong>on</strong> in <str<strong>on</strong>g>th</str<strong>on</strong>g>e sinoatrial node Acta Physica Pol<strong>on</strong>ica B Proceedings Supplement 3 377–390. 618
<str<strong>on</strong>g>European</str<strong>on</strong>g> <str<strong>on</strong>g>C<strong>on</strong>ference</str<strong>on</strong>g> <strong>on</strong> Ma<str<strong>on</strong>g>th</str<strong>on</strong>g>ematical and Theoretical Biology 2011 Heart rate dynamics: models and measures <str<strong>on</strong>g>of</str<strong>on</strong>g> complexity (part I); Wednesday, June 29, 14:30 Danuta Makowiec Institute <str<strong>on</strong>g>of</str<strong>on</strong>g> Theoretical Physics and Astrophysics University <str<strong>on</strong>g>of</str<strong>on</strong>g> Gdańsk, Gdańsk, Poland e-mail: fizdm@univ.gda.pl A. Rynkiewicz J. Wdowczyk-Szulc M. Żarczyńska-Buchowiecka First Department <str<strong>on</strong>g>of</str<strong>on</strong>g> Cardiology, Medical University <str<strong>on</strong>g>of</str<strong>on</strong>g> Gdańsk Heal<str<strong>on</strong>g>th</str<strong>on</strong>g>y aging by multifractal analysis <str<strong>on</strong>g>of</str<strong>on</strong>g> heart interbeat intervals Heart rate resp<strong>on</strong>ds dynamically to various intrinsic and envir<strong>on</strong>mental stimuli. The resp<strong>on</strong>se is supposed to be mediated by aut<strong>on</strong>omic nervous system. Multifractal analysis <str<strong>on</strong>g>of</str<strong>on</strong>g>fers a novel me<str<strong>on</strong>g>th</str<strong>on</strong>g>od to assess <str<strong>on</strong>g>th</str<strong>on</strong>g>is resp<strong>on</strong>se. Fractal properties <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>th</str<strong>on</strong>g>e power spectra in VLF (and ultra-low-frequency (ULF: ≤ 0.0033Hz)) have being analyzed for more <str<strong>on</strong>g>th</str<strong>on</strong>g>an 20 years and <str<strong>on</strong>g>th</str<strong>on</strong>g>ey were found to have prognostic significance in cardiac patients [1] <str<strong>on</strong>g>th</str<strong>on</strong>g>ough also <str<strong>on</strong>g>th</str<strong>on</strong>g>ey were questi<strong>on</strong>ed when <str<strong>on</strong>g>th</str<strong>on</strong>g>ey were used for an individual [2]. Therefore <str<strong>on</strong>g>th</str<strong>on</strong>g>e reliability <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>th</str<strong>on</strong>g>e approach has to be carefully validated. The me<str<strong>on</strong>g>th</str<strong>on</strong>g>od <str<strong>on</strong>g>of</str<strong>on</strong>g> effective reading <str<strong>on</strong>g>of</str<strong>on</strong>g> multifractal properties will be described. The me<str<strong>on</strong>g>th</str<strong>on</strong>g>od c<strong>on</strong>sists <str<strong>on</strong>g>of</str<strong>on</strong>g> two way analysis pertaining each signal. In parallel, a given signal analysis and integrated signal analysis are performed. Differences between <str<strong>on</strong>g>th</str<strong>on</strong>g>e multifractal spectra received from <str<strong>on</strong>g>th</str<strong>on</strong>g>e same signal are found important in discriminating m<strong>on</strong><str<strong>on</strong>g>of</str<strong>on</strong>g>ractality from multifractality. The me<str<strong>on</strong>g>th</str<strong>on</strong>g>od is used in study 24-hour ECG recordings <str<strong>on</strong>g>of</str<strong>on</strong>g> RR interbeat intervals <str<strong>on</strong>g>of</str<strong>on</strong>g> 48 elderly volunteers, 40 middle-aged pers<strong>on</strong>s and 36 young adults in order to assess <str<strong>on</strong>g>th</str<strong>on</strong>g>e effect <str<strong>on</strong>g>of</str<strong>on</strong>g> aging <strong>on</strong> aut<strong>on</strong>omic regulati<strong>on</strong> during normal activity in heal<str<strong>on</strong>g>th</str<strong>on</strong>g>y adults. The variability <str<strong>on</strong>g>of</str<strong>on</strong>g> heart interbeat intervals was evaluated in <str<strong>on</strong>g>th</str<strong>on</strong>g>e VLF band (32-420 RR intervals) to preserve links to standard measures <str<strong>on</strong>g>of</str<strong>on</strong>g> heart rate variability [1]. The nocturnal and diurnal multifractality was c<strong>on</strong>sidered separately. The switch from multi- to m<strong>on</strong><str<strong>on</strong>g>of</str<strong>on</strong>g>ractality is observed between diurnal and nocturnal series in <str<strong>on</strong>g>th</str<strong>on</strong>g>e group <str<strong>on</strong>g>of</str<strong>on</strong>g> young adults. That change can be directly related to <str<strong>on</strong>g>th</str<strong>on</strong>g>e circadian alternati<strong>on</strong> in <str<strong>on</strong>g>th</str<strong>on</strong>g>e central mechanisms c<strong>on</strong>trolling <str<strong>on</strong>g>th</str<strong>on</strong>g>e temporal organizati<strong>on</strong> <str<strong>on</strong>g>of</str<strong>on</strong>g> cardiovascular system — nocturnal dominance <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>th</str<strong>on</strong>g>e vagal t<strong>on</strong>e versus sympa<str<strong>on</strong>g>th</str<strong>on</strong>g>etic main drive during daily activities. Wi<str<strong>on</strong>g>th</str<strong>on</strong>g> aging <str<strong>on</strong>g>th</str<strong>on</strong>g>e multifractal structure <str<strong>on</strong>g>of</str<strong>on</strong>g> nocturnal signals declines. Our observati<strong>on</strong>s are c<strong>on</strong>sistent wi<str<strong>on</strong>g>th</str<strong>on</strong>g> [3] <str<strong>on</strong>g>th</str<strong>on</strong>g>at imbalance in <str<strong>on</strong>g>th</str<strong>on</strong>g>e aut<strong>on</strong>omic c<strong>on</strong>trol due to heal<str<strong>on</strong>g>th</str<strong>on</strong>g>y aging should be related to changes <str<strong>on</strong>g>th</str<strong>on</strong>g>at are emerging from <str<strong>on</strong>g>th</str<strong>on</strong>g>e vagal t<strong>on</strong>e, what in c<strong>on</strong>sequence results in increasing activity <str<strong>on</strong>g>of</str<strong>on</strong>g> sympa<str<strong>on</strong>g>th</str<strong>on</strong>g>etic modulati<strong>on</strong>. References. [1] Tan C O, Cohen M A, Eckberg D L and Taylor J A, Fractal properties <str<strong>on</strong>g>of</str<strong>on</strong>g> human heart period variability: physiological and me<str<strong>on</strong>g>th</str<strong>on</strong>g>odological implicati<strong>on</strong>s J. Physiol. 587 3929 [2] Task Force <str<strong>on</strong>g>of</str<strong>on</strong>g> <str<strong>on</strong>g>th</str<strong>on</strong>g>e <str<strong>on</strong>g>European</str<strong>on</strong>g> Society <str<strong>on</strong>g>of</str<strong>on</strong>g> Cardiology <str<strong>on</strong>g>th</str<strong>on</strong>g>e Nor<str<strong>on</strong>g>th</str<strong>on</strong>g> American Society <str<strong>on</strong>g>of</str<strong>on</strong>g> Pacing and Electrophysiology 1996 Heart rate variability. Standards <str<strong>on</strong>g>of</str<strong>on</strong>g> measurement, physiological interpretati<strong>on</strong>, and clinical use Eur. Heart J. 17 354–81 619
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