Effect of different levels of briefly sustained ventricular pressure on arrhythmia in the isolated working rat heart

1991 ◽  
Vol 81 (6) ◽  
pp. 715-721 ◽  
Author(s):  
M. A. James ◽  
J. V. Jones
Keyword(s):  
Wall Stress ◽  
Ventricular Pressure ◽  
Ventricular Wall ◽  
Hypertensive Rats ◽  
Arrhythmogenic Effect ◽  
Rat Hearts ◽  
Short Period ◽  
Working Heart ◽  
Different Levels ◽  
Working Rat Heart

1. The effect of different levels of ventricular pressure upon the prevalence of ventricular arrhythmias has been studied in 42 rat hearts by using the isolated working heart model. 2. The results have shown that there is an increased prevalence of arrhythmia at the highest levels of pressure tested in hearts from both normal and hypertensive rats. In hearts from normal rats total ectopic counts were 304 at 140 mmHg and 150 at 60 mmHg (P < 0.05). In hearts from hypertensive rats total ectopic counts were 4217 at 180 mmHg and 2179 at 100 mmHg (P < 0.05). 3. Hearts from hypertensive rats demonstrated significantly more ectopic activity than hearts from normal rats at all test pressures. Median values for ectopic counts for each study period were 68 in hearts from hypertensive rats and seven in hearts from normotensive rats (P < 0.001). 4. There was evidence that the increased arrhythmia observed was not due to ischaemia or fatigue, and it seems likely that these effects of raised pressure are due to its effect on ventricular wall stress. The differences between various pressures were relatively small, but do suggest that a sustained increase in ventricular wall stress is arrhythmogenic. 5. This small arrhythmogenic effect over the relatively short period of these studies may be of much greater significance when considered in the context of the prolonged periods for which the diseased heart may be subjected to raised wall stress.

EMD 57033 Enhances Arrhythmias Associated with Increased Wall-Stress in the Working Rat Heart

1995 ◽  
Vol 89 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Stephen J. Evans ◽  
Allan J. Levi ◽  
John A. Lee ◽  
John V. Jones
Keyword(s):  
Ventricular Arrhythmia ◽  
Intracellular Calcium ◽  
Rat Heart ◽  
Ventricular Arrhythmias ◽  
Wall Stress ◽  
Ventricular Afterload ◽  
Therapeutic Compound ◽  
Different Levels ◽  
Ventricular Ectopics ◽  
Working Rat Heart

1. EMD 57033 produces a positive inotropic effect by increasing the sensitivity of cardiac muscle myofilaments to calcium. Since the elevation in intracellular calcium produced by conventional inotropic compounds is thought to be arrhythmogenic, it is hoped that compounds such as EMD 57033 may increase cardiac output without exacerbating arrhythmias in patients with cardiac failure. This is the first study to examine whether EMD 57033 influences the susceptibility of the heart to ventricular arrhythmias. 2. We used the isolated working rat heart to investigate the effect of EMD 57033 on wall-stress-induced ventricular arrhythmia. Arrhythmias were induced by increases in ventricular afterload, and the effect of 2 μmol/l EMD 57033 on ventricular arrhythmias was investigated. The effect of 2 μmol/l EMD 57033 on contractility and arrhythmias was also assessed in the presence of different levels of perfusate calcium. 3. EMD 57033 was positively inotropic in the working rat heart, but it also produced a reversible increase in wall-stress-induced ventricular arrhythmia. The incidence of both ventricular ectopics and complex arrhythmias such as ventricular tachycardia were significantly increased by EMD 57033. Arrhythmias increased progressively as the level of perfusate calcium was raised within the physiological range. 4. The mechanism by which EMD 57033 increases wall-stress-induced arrhythmia is unclear, but it seems unlikely to be directly due to elevation of intracellular calcium. Further studies of the arrhythmogenic profile of this novel compound are required in a variety of models to assess its suitability and safety as a potentially therapeutic compound in heart failure.

Prior treatment with heat shock attenuates the stress response in isolated working rat hearts

1995 ◽  
Vol 73 (1-2) ◽  
pp. 31-39
Author(s):  
Todd A. Dakin ◽  
R. William Currie
Keyword(s):  
Heat Shock ◽  
Control Mechanism ◽  
Negative Control ◽  
Northern Analysis ◽  
Moderate Increase ◽  
Flow Rates ◽  
Rat Hearts ◽  
Heart Perfusion ◽  
Paired Control ◽  
Working Heart

We examined the expression of the mRNAs encoding for the inducible heat shock protein (HSP) 71 and the constitutively synthesized HSP73 in control and 24-h post-heat-shocked (post-HS) hearts during isolated working heart perfusion. Paired control and 24-h post-HS rat hearts were perfused in the working heart mode for 1, 2, 3, or 4 h. Aortic and coronary flow rates and heart rates were not different between the control and 24-h post-HS hearts during the perfusion periods. After perfusion, total RN A was extracted and separated by gel electrophoresis. RNA was blotted to membranes, subsequently probed with 32P-labelled cDNA probes for HSP71 and HSP73 transcripts, and autoradiographed. Control hearts showed a sharp increase in transcripts for HSP71 and a more moderate increase in transcripts for HSP73 accumulation during perfusion. However, the increase in HSP71 and HSP73 transcripts in the HS hearts was markedly less than that in the control hearts. This suppression in gene expression in the HS hearts seems to suggest a negative control mechanism regulating transcription of mRNA encoding HSP71 and HSP73.Key words: mRNA, heart, Northern analysis, working heart perfusion, heat shock.

scholarly journals Left Ventricular Wall Stress Calculated from One-Plane Cineangiography

1970 ◽  
Vol 26 (1) ◽  
pp. 71-83 ◽  
Author(s):  
HERMAN L. FALSETTI ◽  
ROBERT E. MATES ◽  
COLIN GRANT ◽  
DAVID G. GREENE ◽  
IVAN L. BUNNELL
Keyword(s):  
Wall Stress ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Ventricular Wall

scholarly journals Mechanically Unloading the Left Ventricle Before Coronary Reperfusion Reduces Left Ventricular Wall Stress and Myocardial Infarct Size

Circulation ◽  
2013 ◽  
Vol 128 (4) ◽  
pp. 328-336 ◽  
Author(s):  
Navin K. Kapur ◽  
Vikram Paruchuri ◽  
Jose Angel Urbano-Morales ◽  
Emily E. Mackey ◽  
Gerard H. Daly ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Infarct Size ◽  
Myocardial Infarct ◽  
Wall Stress ◽  
Left Ventricular ◽  
Left Ventricular Wall ◽  
Myocardial Infarct Size ◽  
Ventricular Wall ◽  
Coronary Reperfusion

The Success of Cognitive Activity of Students of the Northern (Arctic) Federal University with Different Levels of Anxietyin Different Time Conditions

2021 ◽  
Vol 18 (1) ◽  
pp. 52-59
Author(s):  
A.I. Taleeva ◽  
◽  
I.T. Madumarova ◽  
N.V. Zvyagina ◽  
◽  
...  
Keyword(s):  
Emotional State ◽  
Cognitive Task ◽  
Cognitive Activity ◽  
Whole Body ◽  
Modern World ◽  
Short Period ◽  
Personal Anxiety ◽  
Psychophysiological Testing ◽  
Short Time ◽  
Different Levels

The dynamic development of the modern world requires the processing and development of a large enough amount of information in a short period of time, which leads to a violation of the psychophysiological and psycho-emotional balance of the person. Violation of the psycho-emotional state leads to the development of increased anxiety. Students need to learn a lot of information in a very short time. The time limit affects students as a stress factor, leads to increased stress and therefore negatively affects the quality of work and in general on the whole body. The aim of the study is to determine the success of cognitive tasks by students of the Northern (Arctic) Federal University with different levels of anxiety in different time conditions. The study used a psychophysiological testing device to determine the level of situational and personal anxiety, to assess the psycho-emotional state used the technique of simple visual-motor reaction, to determine the success of the cognitive task were presented words with one missing letter.

Sign in / Sign up

Export Citation Format

Share Document