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| Format: | Artículo científico |
| Language: | en |
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Sociedad Mexicana de Física A.C.
2012
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| Online Access: | https://www.redalyc.org/articulo.oa?id=57030391014 |
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Table of Contents:
- The problem of quantifying the reversibility and efficiency of the cardiac cycle based on the analysis of cardiac interbeat time series A. Muñoz-Diosdado A. Alonso-Martínez G. Gálvez-Coyt E. Calleja-Quevedo Física, Astronomía y Matemáticas efficiency Cardiac cycle irreversibility time series analysis Cardiac efficiency is an important medical research subject, because it is reduced in certain pathophysiological disease states, for instance, obesity and insulin resistance cause efficiency reduction. Taking into account thermodynamic basic concepts and doing some approximations, it is easy to get expressions to evaluate the efficiency of the cardiac cycle. However, physiological variables which depend on the efficiency of the cardiac cycle have a significant variability in the day, even at rest. This variability has been evaluated in various ways, for instance, spectral, correlational and fractal analysis. At short-term this cycle is quasi-reversible, but at long term it is irreversible. This work discusses two important aspects of the cardiac cycle related with thermodynamic concepts and how nonlinear dynamics techniques can be used to study them: the first is the calculation of the cycle efficiency and the second the quantification of irreversibility rather than of the cardiac cycle, but the analysis of heartbeat time series obtained with a Holter that registered ECG signals during 24 hours of healthy individuals, and patients with congestive heart failure (CHF). The results show that there is a variability of cardiac efficiency along the day for both healthy and CHF patients, and there is a substantial reduction in efficiency for CHF patients. The values obtained for the average efficiency approach to the values reported in the medical literature. However, there are problems associated with the lack of data of some physiological variables, not only of pressure, but also of oxygen consumption by the heart and the metabolic energy per liter of oxygen consumed. We show a method to evaluate the irreversibility of heartbeat time series and present results that tend to relate the healthy state with the irreversibility of the heartbeat series and the heart failure with the reversibility of the same series. 2012 artículo científico 0035-001X https://www.redalyc.org/articulo.oa?id=57030391014 en http://www.redalyc.org/revista.oa?id=570 Revista Mexicana de Física application/pdf Sociedad Mexicana de Física A.C. Revista Mexicana de Física (México) Num.1 Vol.58