CRT Past, Present, and Future Directions: Toward Intelligent Responders Selection and Optimizing Pacing Modalities

Congestive heart failure (CHF) is a serious health problem affecting all nations of world. Its impact is increasing with increasing individual age. Ventricular dyssynchrony is well known to contribute to pathophysiological deterioration in more than one-third of CHF subjects. The therapeutic choices of CHF witnessed long decades of stagnant periods and a relative paucity of effective treatment. The discovery of the electrical therapy that is capable of reversing ventricular dyssynchrony, in the form of cardiac resynchronization therapy (CRT), is a true revolution in the timeline of CHF management. Despite the early enthusiasm associated with CRT implantations started in 2001, we know from the last two decades’ experience that non-responders constitute to nearly 40% of all CRT patients. This chapter is devoted to reviewing the past, present and future of CRT with special attention on better intelligent detection of the electrical substrate responsive to CRT as well as optimizing the choice of CRT subjects using the latest knowledge in electrocardiographic and state-of-art imagining technologies. Novel future directions are discussed with new scientific philosophies capable of optimizing CRT. Promising new implants techniques such as endocardial pacing of the left ventricle, His bundle pacing as well as His-optimized cardiac resynchronization therapy are discussed

Synchronization of human autonomic nervous system rhythms with geomagnetic activity in human subjects

A coupling between geomagnetic activity and the human nervous system's function was identified by virtue of continuous monitoring of heart rate variability (HRV) and the time-varying geomagnetic field over a 31-day period in a group of 10 individuals who went about their normal day-to-day lives. A time series correlation analysis identified a response of the group's autonomic nervous systems to various dynamic changes in the solar, cosmic ray, and ambient magnetic field. Correlation coefficients and p values were calculated between the HRV variables and environmental measures during three distinct time periods of environmental activity. There were significant correlations between the group's HRV and solar wind speed, Kp, Ap, solar radio flux, cosmic ray counts, Schumann resonance power, and the total variations in the magnetic field. In addition, the time series data were time synchronized and normalized, after which all circadian rhythms were removed. It was found that the participants' HRV rhythms synchronized across the 31-day period at a period of approximately 2.5 days, even though all participants were in separate locations. Overall, this suggests that daily autonomic nervous system activity not only responds to changes in solar and geomagnetic activity, but is synchronized with the time-varying magnetic fields associated with geomagnetic field-line resonances and Schumann resonances

New approach for visualization of relationships between RR and JT intervals

<div><p>This paper presents the concept of perfect matrices of Lagrange differences which are used to analyze relationships between RR and JT intervals during the bicycle ergometry exercise. The concept of the perfect matrix of Lagrange differences, its parameters, the construction of the load function and the corresponding optimization problem, the introduction of internal and external smoothing, embedding of the scalar parameter time series into the phase plane—all these computational techniques allow visualization of complex dynamical processes taking place in the cardiovascular system during the load and the recovery processes. Detailed analysis is performed with one person’s RR and JT records only—but the presented techniques open new possibilities for novel interpretation of the dynamics of the cardiovascular system.</p></div

Long-term study of heart rate variability responses to changes in the solar and geomagnetic environment

This long-term study examined relationships between solar and magnetic factors and the time course and lags of autonomic nervous system (ANS) responses to changes in solar and geomagnetic activity. Heart rate variability (HRV) was recorded for 72 consecutive hours each week over a five-month period in 16 participants in order to examine ANS responses during normal background environmental periods. HRV measures were correlated with solar and geomagnetic variables using multivariate linear regression analysis with Bonferroni corrections for multiple comparisons after removing circadian influences from both datasets. Overall, the study confirms that daily ANS activity responds to changes in geomagnetic and solar activity during periods of normal undisturbed activity and it is initiated at different times after the changes in the various environmental factors and persist over varying time periods. Increase in solar wind intensity was correlated with increases in heart rate, which we interpret as a biological stress response. Increase in cosmic rays, solar radio flux, and Schumann resonance power was all associated with increased HRV and parasympathetic activity. The findings support the hypothesis that energetic environmental phenomena affect psychophysical processes that can affect people in different ways depending on their sensitivity, health status and capacity for self-regulation