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Chronobiology in cardiology
1Department of Medicine I, Tokyo Women's Medical College, Daini Hospital, Japan.
Insights
Circadian rhythms influence heart attacks and strokes. Advanced ambulatory monitoring systems now track heart rate variability and physical activity, aiding clinical practice.
Area of Science:
- Cardiology
- Chronobiology
- Biomedical Engineering
Background:
- Established circadian periodicity in cardiovascular events like myocardial infarction and stroke.
- Documented circadian rhythms in ventricular arrhythmias among myocardial infarction patients.
- Advances in chronocardiology are driven by improved ambulatory ECG monitoring and software.
Purpose of the Study:
- To review current topics in heart rate (HR) variability analysis.
- To highlight recent advancements in ambulatory blood pressure (BP) monitoring systems.
- To introduce a new physical activity monitoring system for evaluating HR and BP changes.
Main Methods:
- Analysis of heart rate variability using RR50 estimation (cosine fitting), Lorenz plots, and power spectral analysis (maximum entropy method, fast Fourier transform).
- Utilized a newly developed ambulatory monitoring system for physical activity, heart rate (HR), and blood pressure (BP).
- Evaluated episodic changes in HR and BP and differentiated individual lifestyles (e.g., morningness vs. eveningness).
Main Results:
- Introduced key methods for assessing heart rate variability, including RR50, Lorenz plots, and spectral analysis.
- Demonstrated the utility of advanced ambulatory monitoring systems for tracking cardiovascular parameters.
- Highlighted the capability of the new system to assess physical activity and correlate it with HR and BP variations.
Conclusions:
- Recent technological advancements in ambulatory monitoring systems are significant for clinical applications.
- These systems offer valuable insights into circadian rhythms of cardiovascular events and individual lifestyle impacts.
- The developed monitoring system is poised for integration into clinical practice.
Abstract:
In these years, circadian periodicity in the onset of myocardial ischemia, myocardial infarction, sudden cardiac death and ischemic stroke has been confirmed by several investigators. There has also been reported that there exists a significant circadian rhythm in ventricular arrhythmias in patients with myocardial infarction. These recent advances in chronocardiology depend on a development of a high quality built-in A/D converter in ambulatory ECG monitoring system and a remarkably developed sophisticated software. One of the most current topics in recent years is heart rate (HR) variability. As an index of HR variability, RR50 is frequently estimated by the cosine fitting technique. Next, we analyzed the so-called Lorenz plot for another index of HR variability, that is preceding R-R intervals and coupling intervals were plotted sequentially every 3 hours on the abscissa and ordinate, respectively. Finally, we investigated HR variability by power spectral analysis of R-R intervals both by the maximum entropy method and the fast Fourier transform. Mainly, in this paper, we introduced current topics in HR variability, but recent advances in ambulatory blood pressure (BP) monitoring system are also strikingly remarkable. Our newly developed monitoring system of physical activity donated quite a few informations evaluating episodic changes of HR and BP. This device was also useful for finding out the difference between the individual life styles, such as the eveningness versus morningness. In conclusion, these very recent advances in ambulatory monitoring system should be really available for the clinical practice from this time onward.