Following one's heart: cardiac rhythms gate central initiation of sympathetic reflexes

Central nervous processing of environmental stimuli requires integration of sensory information with ongoing autonomic control of cardiovascular function. Rhythmic feedback of cardiac and baroreceptor activity contributes dynamically to homeostatic autonomic control. We examined how the processing of brief somatosensory stimuli is altered across the cardiac cycle to evoke differential changes in bodily state. Using functional magnetic resonance imaging of brain and noninvasive beat-to-beat cardiovascular monitoring, we show that stimuli presented before and during early cardiac systole elicited differential changes in neural activity within amygdala, anterior insula and pons, and engendered different effects on blood pressure. Stimulation delivered during early systole inhibited blood pressure increases. Individual differences in heart rate variability predicted magnitude of differential cardiac timing responses within periaqueductal gray, amygdala and insula. Our findings highlight integration of somatosensory and phasic baroreceptor information at cortical, limbic and brainstem levels, with relevance to mechanisms underlying pain control, hypertension and anxiety

Integrative Approach - New Level Knowledge of Functions: Opportunities and Prospects

In this article, the example of the mechanisms of heart rhythmogenesis in the intact organism is used to demonstrate the new capabilities provided by an integrative approach. It is shown that the rhythm is formed in the brain, transmitted to the heart in the form of signals along the vagus nerves and reproduces the heart. Evidence: the heart rhythm reproduces the natural efferent signals in the vagus nerves in the cardio-respiratory synchronism and in the intact organism sino-atrial node performs the functions of the latent pacemaker. Integration of the two hierarchical levels of rhythmogenesis (brain and intracardiac) provides the reliability and functional perfection of cardiac rhythm generation in the body. It is expedient to extend the presented methodology for scientific analysis to other organism systems

The ECG Atlas of Cardiac Rhythms

In the introduction to his book, Rob Scott Millar states: “This is not a textbook. Its core value depends on the variety of real ECG traces and their interpretation which will, hopefully, assist you in interpreting similar rhythms that you encounter in your practises”. In stating thus, his humility may lead you to underestimate the value of this book which is filled with pearls that only an experienced electrophysiologist and enthusiastic teacher of Rob Scott Millar’s stature can provide. His humble description should rather read: “Its core value depends on the variety of real ECG traces and their interpretation which will definitely assist you in interpreting similar rhythms that you encounter in your practises.

Termination of Reentry in an Inhomogeneous Ring of Model Cardiac Cells

Reentrant waves propagating in a ring or annulus of excitable media model is the basic mechanism underlying a major class of irregular cardiac rhythms known as anatomical reentry. Such reentrant waves are terminated by rapid electrical stimulation (pacing) from an implantable device. Because the mechanisms of such termination are poorly understood, we study pacing of anatomical reentry in a one-dimensional ring of model cardiac cells. For realistic off-circuit pacing, our model-independent results suggest that circuit inhomogeneities, and the electrophysiological dynamical changes they introduce, may be essential for terminating reentry in some cases.Comment: 8 pages, 2-column LaTex (7 eps figures included); v2 includes additional results and figures as in published versio

Retrospective study of the correlation of serum potassium concentrations and the findings of heart auscultation in calves with neonatal diarrhea

A retrospective study was conducted of clinical records of calves with neonatal diarrhea up to the age of 14 days concerning certain aspects of blood potassium concentration and heart rate and rhythm. No correlation could be found between heart rates and serum potassium concentrations. Bradycardia was no indicator of hyperkalemia, nor could hyperkalemia be ruled out in animals with tachycardia. Cardiac arrhythmias were not associated with pronounced kyperkalemia, and did not indicate a poor prognosis. It was concluded that, at least in clinical cases of neonatal calf diarrhea, heart rate and rhythm are subject to complex influences and yield no information on the actual serum potassium concentration in a particular animal

Algorithm for Mobile Platform-Based Real-Time QRS Detection

Recent advancements in smart, wearable technologies have allowed the detection of various medical conditions. In particular, continuous collection and real-time analysis of electrocardiogram data have enabled the early identification of pathologic cardiac rhythms. Various algorithms to assess cardiac rhythms have been developed, but these utilize excessive computational power. Therefore, adoption to mobile platforms requires more computationally efficient algorithms that do not sacrifice correctness. This study presents a modified QRS detection algorithm, the AccYouRate Modified Pan–Tompkins (AMPT), which is a simplified version of the well-established Pan–Tompkins algorithm. Using archived ECG data from a variety of publicly available datasets, relative to the Pan–Tompkins, the AMPT algorithm demonstrated improved computational efficiency by 5–20×, while also universally enhancing correctness, both of which favor translation to a mobile platform for continuous, real-time QRS detection

The first international workshop on the role and impact of mathematics in medicine: a collective account

The First International Workshop on The Role and Impact of Mathematics in Medicine (RIMM) convened in Paris in June 2010. A broad range of researchers discussed the difficulties, challenges and opportunities faced by those wishing to see mathematical methods contribute to improved medical outcomes. Finding mechanisms for inter- disciplinary meetings, developing a common language, staying focused on the medical problem at hand, deriving realistic mathematical solutions, obtainin