Search results for "Rhythm"

An integrated approach based on uniform quantization for the evaluation of complexity of short-term heart period variability: Application to 24 h Hol…

2007

We propose an integrated approach based on uniform quantization over a small number of levels for the evaluation and characterization of complexity of a process. This approach integrates information-domain analysis based on entropy rate, local nonlinear prediction, and pattern classification based on symbolic analysis. Normalized and non-normalized indexes quantifying complexity over short data sequences (∼300 samples) are derived. This approach provides a rule for deciding the optimal length of the patterns that may be worth considering and some suggestions about possible strategies to group patterns into a smaller number of families. The approach is applied to 24 h Holter recordings of …

Segmental dyskinesia in Wolff–Parkinson–White syndrome: A possible cause of dilatative cardiomyopathy

2006

Wolff-Parkinson-White (WPW) is a syndrome characterized by the presence of an accessory pathway that skipping A-V node may lead the electrical stimulus from the atrium directly to the ventricle. Some studies reported the finding of myocardial dyskinesia in the segments precociously activated by the accessory pathway, at echocardiogram and at nuclear cardiac study. Soria et al. reported, in 1985, an increased incidence of dilative cardiomyopathy in patients with WPW. The pathophysiological pathway that leads to ventricular dilation may be due to the increase of end-diastolic pressure secondary to a tachycardia-induced cardiomyopathy. Tachycardia-induced cardiomyopathy is usually secondary to…

Rare cardiomyopathies: Diagnostic features

2013

Cardiomyopathies (CM) are an important and heterogeneous group of diseases affecting the myocardium. They can induce mechanical and/or electrical disorders and are due to a variety of causes, they frequently are genetic. However, since their high number and their clinical complexity, the identification is still a challenge. Echocardiography is a very useful tool in the assessment of CM. In this review we aim to define the typical clinical features and to discuss the main diagnostic tool, above all echocardiography that can help physicians in the correct assessment of CM.

The cholesterol paradox in atrial fibrillation: results from the LIPIDOGRAM 2015 study

2020

Abstract Background High blood lipid levels are known risk factors for atherosclerotic cardiovascular events, but associations between lipid levels and atrial fibrillation (AF) are unclear. Some previous studies have suggested an inverse association between lipid levels and AF referred to as the “cholesterol paradox”. Purpose To examine the prevalence of AF by differing lipid levels in a large population-based study of almost 14,000 adults in Poland. Methods The LIPIDOGRAM 2015 study is a cross-sectional study of adults aged 18 years and older recruited in Poland in 2015/2016 by 438 family physicians. Poisson regression models with robust variance were used to estimate prevalence ratios (PR…

The interaction between circadian rhythms of endothelial function: resting versus recruitable endothelial function

2013

Time-related changes in size of nuclei of pinealocytes in rats

1981

In a study of 96 adult male Sprague-Dawley rats, da- and time-related changes of the mean nuclear volume of pinealocytes were determined with the aim of testing the reproducibility of the karyometric findings described by Quay and Renzoni (1966). It is shown (i) that statistically significant differences exist between the central and peripheral mean volumes of pinealocyte nuclei/group of animals and time point (p less than 0.001), (ii) that the day and time related differences are statistically different in both regions (p less than 0.001), (iii) that in the center and periphery of the pineal body different diurnal patterns exist, and (iv) that the diurnal patterns are not parallel in the t…

Cortical Temperature Change: A Tool for Modulating Brain States?12

2016

Reduction in temperature depolarizes neurons by a partial closure of potassium channels but decreases the vesicle release probability within synapses. Compared with cooling, neuromodulators produce qualitatively similar effects on intrinsic neuronal properties and synapses in the cortex. We used this similarity of neuronal action in ketamine-xylazine-anesthetized mice and non-anesthetized mice to manipulate the thalamocortical activity. We recorded cortical electroencephalogram/local field potential (LFP) activity and intracellular activities from the somatosensory thalamus in control conditions, during cortical cooling and on rewarming. In the deeply anesthetized mice, moderate cortical co…

Large hiatal hernia at chest radiography in a woman with cardiorespiratory symptoms

2012

Hiatal hernia (HH) is a frequent entity. Rarely, it may exert a wide spectrum of clinical presentations mimicking acute cardiovascular events such as angina-like chest pain until manifestations of cardiac compression that can include postprandial syncope, exercise intolerance, respiratory function, recurrent acute heart failure, and hemodynamic collapse. A 69-year-old woman presented to the emergency department complaining of fatigue on exertion, cough, and episodes of restrosternal pain with less than 1 hour of duration. Her medical history only included some episodes of bronchitis and no history of hypertension. The 12-lead electrocardiogram demonstrated sinus rhythm with right bundle-bra…

How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

2015

This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1). For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace chang…

Endogenous fluctuations of DNA topology in the chloroplast of Chlamydomonas reinhardtii.

1998

DNA supercoiling in the chloroplast of the unicellular green alga Chlamydomonas reinhardtii was found to change with a diurnal rhythm in cells growing in alternating 12-h dark-12-h light periods. Highest and lowest DNA superhelicities occurred at the beginning and towards the end of the 12-h light periods, respectively. The fluctuations in DNA supercoiling occurred concurrently and in the same direction in two separate parts of the chloroplast genome, one containing the genes psaB, rbcL, and atpA and the other containing the atpB gene. Fluctuations were not confined to transcribed DNA regions, indicating simultaneous changes in DNA conformation all over the chloroplast genome. Because the d…