Search results for "HEART RATE"

A mathematical model of cardiovascular dynamics for the diagnosis and prognosis of hemorrhagic shock

2020

Abstract A variety of mathematical models of the cardiovascular system have been suggested over several years in order to describe the time-course of a series of physiological variables (i.e. heart rate, cardiac output, arterial pressure) relevant for the compensation mechanisms to perturbations, such as severe haemorrhage. The current study provides a simple but realistic mathematical description of cardiovascular dynamics that may be useful in the assessment and prognosis of hemorrhagic shock. The present work proposes a first version of a differential-algebraic equations model, the model dynamical ODE model for haemorrhage (dODEg). The model consists of 10 differential and 14 algebraic e…

Are double potentials markers of a specific zone of the atrioventricular junction in the isolated rabbit heart?

1997

A study is made of the characteristics of the atrial potentials recorded in the Koch triangle and its proximity, their variations on modifying the site of cardiac pacing, and their usefulness as markers of a distinct zone of the AV junction. In 12 isolated and perfused rabbit heart preparations an analysis was made of the endocardial atrial electrograms recorded with a multiple electrode positioned in the AV junction. The electrograms were obtained during spontaneous rhythm and on pacing at the crista terminalis (CT), interatrial septum (IAS), left atrium, and right ventricle. Double potentials were frequently obtained. On pacing at the CT, high-low double potentials (DP [H-L]) were more fr…

Computerized analysis of normal fetal heart rate pattern throughout gestation.

2009

Objective To analyze the evolution of computerized cardiotocography (cCTG) parameters throughout gestation in a large archive of traces from healthy fetuses. Methods This was a cross-sectional study of the first cCTG record from 4412 singleton fetuses with good pregnancy outcome. Normal ranges of cCTG parameters for 25 to 42 weeks were derived from analysis of only one cCTG record per fetus, and the relationship between the parameters and gestational age was investigated. Results Fetal heart rate (FHR) accelerations, short- and long-term variation overall, duration of episodes of high and low variation and variation in high episodes increased with advancing gestation. In contrast, maternal …

SYNERGISTIC EFFECTS OF ISOSORBIDE DINITRATE AND PINDOLOL ON THE HEART RATE AND PRESSURE RESPONSE TO ISOPROTERENOL

1978

Failure of opioids to affect excitation and contraction in isolated ventricular heart muscle

1989

The opioid agonists morphine (selective for mu-receptors) and ethylketocyclazocine (selective for kappa-receptors), at concentrations evoking strong effects in neuronal structures, did not significantly affect the configuration of the intracellularly recorded action potential and the force of contraction in ventricular heart muscle isolated from guinea pigs, rabbits and man. These results suggest that any changes of heart functions in vivo in response to opioid-like drugs are probably not mediated postsynaptically at the myocardial cell membrane but rather presynaptically, influencing the release of noradrenaline and/or acetylcholine from the nerve terminals.

Good decision-making is associated with an adaptive cardiovascular response to social competitive stress.

2018

Competition elicits different psychological and cardiovascular responses depending on a person's skills. Decision-making has been considered a distal factor that influences competition, but there are no studies analyzing this relationship. Our objective was to analyze whether decision-making affects the response to competition. Specifically, we aimed to test whether good performers on a decision-making test, the Iowa Gambling Task (IGT), showed an adaptive cardiovascular response to competition. In all, 116 participants (44 women) performed the IGT and were classified into Good or Poor decision-makers. Subsequently, they were exposed to a stress task in two different conditions: a face-to-f…

Distinctive body perception mechanisms in high versus low symptom reporters: A neurophysiological model for medically-unexplained symptoms.

2020

Abstract Objective The neurophysiological processes involved in the generation of medically-unexplained symptoms (MUS) remain unclear. This study tested three assumptions of the perception-filter model contributing to MUS: (I.) increased bodily signal strength (II.) decreased filter function, (III.) increased perception. Methods In this cross-sectional, observational study, trait MUS were assessed by a web-based survey (N = 486). The upper and lower decile were identified as extreme groups of high (HSR; n = 29; 26 women; Mage = 26.0 years) and low symptom reporters (LSR; n = 29; 21 women; Mage = 28.4 years). Mean heart rate (HR) and heart rate variability (HRV), and cortisol awakening respo…

Long-term effects of graduated compression stockings on cardiorespiratory performance

2015

ABSTRACT: The use of graduated compression stockings (GCS) in sport has been increasing in the last years due to their potential positive effects for athletes. However, there is little evidence to support whether these types of garments actually improve cardiorespiratory performance. The aim of this study was to examine the cardiorespiratory responses of GCS during running after three weeks of regular use. Twenty recreational runners performed three tests on different days: test 1) ¿ a 5-min maximal effort run in order to determine the participants¿ maximal aerobic speed; and tests 2) and 3) ¿ a fatigue running test of 30 minutes at 80% of their maximal aerobic speed with either GCS or PLAC…

Treadmill and Running Speed Effects on Acceleration Impacts: Curved Non-Motorized Treadmill vs. Conventional Motorized Treadmill

2021

An increase in the popularity of running can be seen over the last decades, with a large number of injuries on it. Most of the running injuries are related to impact accelerations and are due to overuse. In order to reduce the risk of injury or to improve performance and health new treadmill designs have been created, as it can be the curved non-motorized treadmill. The aim of this study was to analyse impact accelerations, spatio-temporal parameters and perceptual differences while running on curved non-motorized treadmill (cNMT) compared to motorized treadmill (MT) at different speeds. Therefore, 27 recreational runners completed two tests consisting of 10 min warm-up and three bouts of 8…

Avoidant coping, verbal-autonomic response dissociation and pain tolerance

2006

Higher autonomic reactivity relative to self-reported discomfort, often found in repressors and avoidant copers might be associated with a diminished perception of bodily symptoms. This study aimed at relating such so-called verbal-autonomic response dissociation to pain tolerance. Eighty-five volunteers underwent a public speaking task and a cold pressor test. Heart rate and negative affect in response to the speech, and pain ratings and facial muscle responses for the cold pressor were obtained. A dissociation score was calculated for each individual in response to speech, thereby subtracting standardized changes in negative affect from standardized changes in heart rate. Response dissoci…