Search results for "Cardiac activity"
showing 7 items of 7 documents
3,4-trans-4-Aryl-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolates—new group of potential cardiotonic drugs
2005
Abstract 3,4- trans -4-Aryl-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolates 6 – 11 were prepared by a Michael reaction of N -acetonylpyridinium chloride with 3-aryl-2-cyanothioacrylamides or by a one-pot three-carbon condensation of N -acetonylpyridinium chloride, aromatic aldehyde and 2-cyanothioacetamide, and their cardiotonic properties were studied. 3,4- trans -5-cyano-2-hydroxy-2-methyl-4-(3-nitrophenyl)-3-(1-pyridinio)-1,2,3,4-tetrahydropyridine-6-thiolate 8 was considered as a lead compound in this series since it in vitro experiments (spontaneously beating rat atria) showed a cardiotonic activity similar to that of milrinone 2 , however compound 8 induced activity at lover co…
Analysis of the Modifications in the Spectral and Morphologic Regularity during Ventricular Fibrillation Produced by Physical Exercise and the Use of…
2015
Chronic physical exercise modifies cardiac activity improving response to malignant arrhythmia and, specifically, ventricular fibrillation (VF). Drug administration as glibenclamide, responsible for K + ATP channel blocking, is also generating a positive response against fibrillation.
Towards Disentangling the Contribution of Different Pathways for the Regulation of Cardiac Activity: A Pilot Study
2020
Heartbeat is dynamically regulated through mediating routes associated with central and peripheral feedback mechanisms. Previous studies focused on the quantification of these mechanisms in the presence of a single stressor. In this pilot study we propose a model aimed to quantify the contribution of different heartbeat regulatory routes while multiple stressors are administrated to the subject. The model is tested with Heart rate Variability (HRV) series from 26 subjects undergoing physical and affective stressors. Results show that the physical stressor prevalently (74%) contributes in mediating cardiac vagal control dynamics in case of concurrent affective elicitation. These results may …
Analysis of the effects of pulsed microwave on cardiac activity
1993
Abstract The exposure of isolated chick embryo hearts to 2.45 GHz pulse modulated microwaves has identified certain phenomena: (1) when the heartbeat was irregular, an appropriate pulse repetition rate caused regularization; (2) during regular beating, an increase of pulse repetition rate similarly increased the heartbeat frequency, until an irregular heartbeat appeared; (3) by applying microwaves, when an arrhythmia occurs, a regular beat appeared after a few seconds. Time correlation between the heartbeat and the modulating pulses revealed that regularization occurs when the modulation pulses, at a frequency close to the natural unperturbed heartbeat, were applied in the ventricular diast…
Variations in physiological responses to thermal stress in congeneric limpets in the Mediterranean Sea
2014
Cardiac activity (Arrhenius breakpoint temperatures and Q10 relationships) and heat shock response (hsp70 expression) were measured in the congeneric limpets Patella rustica, P. caerulea and P. ulyssiponensis in order to test the relationship between their vertical distribution and physiological thermal tolerance. These species exhibit different vertical distributions along Mediterranean shores and despite the narrow tidal range in the Mediterranean, they experience different environmental conditions and consequently had specific thermal windows. Cardiac activity of the upper zoned P. rustica was maintained at higher temperatures than its mid- or low shore counterparts, P. caerulea and P. u…
A Multi-Variate Predictability Framework to Assess Invasive Cardiac Activity and Interactions during Atrial Fibrillation
2017
Objective: This study introduces a predictability framework based on the concept of Granger causality (GC), in order to analyze the activity and interactions between different intracardiac sites during atrial fibrillation (AF). Methods: GC-based interactions were studied using a three-electrode analysis scheme with multi-variate autoregressive models of the involved preprocessed intracardiac signals. The method was evaluated in different scenarios covering simulations of complex atrial activity as well as endocardial signals acquired from patients. Results: The results illustrate the ability of the method to determine atrial rhythm complexity and to track and map propagation during AF. Conc…
Assessing game experience: Heart rate variability, in-game behavior and self-report measures
2014
Assessing game experience by means of recordings of physiological reactions elicited during game play is a technique that has gained popularity in recent years in the field of digital games research. However, since physiological signals are typically linked to several psychological processes, the use of some measures such as cardiac activity or heart rate (HR) remains problematic. The goal of the present study is to investigate to what extent game logs and self-report measures of game experience have a predictive value for heart rate variability during game play. Our results showed that the accurate registration of in-game behaviors by means of game logs carries the potential of providing r…