scholarly journals Novel Patterns of Left Ventricular Mechanical Activity During Experimental Cardiac Arrest in Pigs

2018 ◽  
pp. 391-399 ◽  
Author(s):  
R. SKULEC ◽  
D. ASTAPENKO ◽  
R. CERNA PARIZKOVA ◽  
B. FURST ◽  
M. BILSKA ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
High Frequency ◽  
Low Frequency ◽  
Pulseless Electrical Activity ◽  
Left Ventricular ◽  
Mechanical Activity ◽  
Sublingual Microcirculation ◽  
Surface Ecg ◽  
Group Rate ◽  
Induced Cardiac Arrest

We conducted an experimental study to evaluate the presence of coordinated left ventricular mechanical myocardial activity (LVMA) in two types of experimentally induced cardiac arrest: ventricular fibrillation (VF) and pulseless electrical activity (PEA). Twenty anesthetized domestic pigs were randomized 1:1 either to induction of VF or PEA. They were left in nonresuscitated cardiac arrest until the cessation of LVMA and microcirculation. Surface ECG, presence of LVMA by transthoracic echocardiography and sublingual microcirculation were recorded. One minute after induction of cardiac arrest, LVMA was identified in all experimental animals. In the PEA group, rate of LVMA was of 106±12/min. In the VF group, we identified two patterns of LVMA. Six animals exhibited contractions of high frequency (VFhigh group), four of low frequency (VFlow group) (334±12 vs. 125±32/min, p<0.001). A time from cardiac arrest induction to asystole (19.2±7.2 vs. 7.3±2.2 vs. 8.3±5.5 min, p=0.003), cessation of LVMA (11.3±5.6 vs. 4.4±0.4 vs. 7.4±2.9 min, p=0.027) and cessation of microcirculation (25.3±12.6 vs. 13.4±2.4 vs. 23.2±8.7 min, p=0.050) was significantly longer in VFlow group than in VFhigh and PEA group, respectively. Thus, LVMA is present in both VF and PEA type of induced cardiac arrest and moreover, VF may exhibit various patterns of LVMA.

Abstract P109: Alteration in Intracellular Calcium During Cardiac Arrest

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Satoshi Takeda ◽  
Hiroshi Yoshida ◽  
Takeki Ogawa
Keyword(s):  
Cardiac Arrest ◽  
Intracellular Calcium ◽  
Cell Injury ◽  
Diastolic Pressure ◽  
Pulseless Electrical Activity ◽  
Left Ventricular Pressure ◽  
Cardiac Metabolism ◽  
Left Ventricular ◽  
Free Calcium ◽  
Developed Pressure

AIM: A cytosolic free calcium is an important regulator of cardiac metabolism and contractility, and an increased [Ca2+]i has been implicated in irreversible cell injury and contractile dysfunction. We investigated intracellular calcium ([Ca2+]i) dynamics during cardiac arrest, especially in pulseless electrical activity (PEA) and asystole. METHODS: Rat hearts (n=18) were perfused with a Langendorff system and loaded with Fura-2/AM, as a [Ca2+]i marker, and BCECF/AM, as a pHi marker. Surface fluorescence of the heart was recorded with an intracellular ion analyzer. A latex balloon was inserted into the left ventricle to monitor left ventricular pressure. Sustained normo-thermic cardiac arrest was induced for 20 min by clamping the aortic cannula. RESULTS: After clamping (cardiac arrest), the left ventricular developed pressure decreased significantly, from 84.3±11 mmHg to 3.88±0.7 mmHg (p<0.01) at 2min. The rhythm was PEA in all cases in this period, followed by asystole. The amplitude of the [Ca2+]i transient (0.30±0.03) was maintained at 2 min, but further significant increases were observed in both systolic (1.14±0.04, p<0.01) and diastolic levels of [Ca2+]i (0.84±0.04, p<0.05), when compared with pre-arrest levels. The [Ca2+]i transient disappeared 4.7±0.6 min. The diastolic [Ca2+]i increased gradually after 5 min to 20 min. This diastolic [Ca2+]i increase was parallel with the increase in left ventricular end diastolic pressure (indicated ischemic contracture). The pHi increased (to 7.6±1.0) immediately after clamping. Thereafter pHi decreased rapidly and remained steady (at pH 6.6±0.6). CONCLUSIONS: The change in the [Ca2+]i-pressure relationship rather than change in the amplitude of the [Ca2+]i transient was the main contributor in the early cardiac arrest phase. The diastolic [Ca2+]i increase might induce irreversible cell injury in the late cardiac arrest phase.

scholarly journals Pulseless Electrical Activity as the Initial Cardiac Arrest Rhythm: Importance of Preexisting Left Ventricular Function

2021 ◽  
Author(s):  
Daniel I. Ambinder ◽  
Kaustubha D. Patil ◽  
Hikmet Kadioglu ◽  
Pace S. Wetstein ◽  
Richard S. Tunin ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Ventricular Fibrillation ◽  
Left Ventricular Dysfunction ◽  
Coronary Occlusion ◽  
Ventricular Dysfunction ◽  
Pulseless Electrical Activity ◽  
Left Ventricular ◽  
Severe Left Ventricular Dysfunction ◽  
Acute Coronary Occlusion ◽  
Coronary Ischemia

Background Pulseless electrical activity (PEA) is a common initial rhythm in cardiac arrest. A substantial number of PEA arrests are caused by coronary ischemia in the setting of acute coronary occlusion, but the underlying mechanism is not well understood. We hypothesized that the initial rhythm in patients with acute coronary occlusion is more likely to be PEA than ventricular fibrillation in those with prearrest severe left ventricular dysfunction. Methods and Results We studied the initial cardiac arrest rhythm induced by acute left anterior descending coronary occlusion in swine without and with preexisting severe left ventricular dysfunction induced by prior infarcts in non–left anterior descending coronary territories. Balloon occlusion resulted in ventricular fibrillation in 18 of 34 naïve animals, occurring 23.5±9.0 minutes following occlusion, and PEA in 1 animal. However, all 18 animals with severe prearrest left ventricular dysfunction (ejection fraction 15±5%) developed PEA 1.7±1.1 minutes after occlusion. Conclusions Acute coronary ischemia in the setting of severe left ventricular dysfunction produces PEA because of acute pump failure, which occurs almost immediately after coronary occlusion. After the onset of coronary ischemia, PEA occurred significantly earlier than ventricular fibrillation (<2 minutes versus 20 minutes). These findings support the notion that patients with baseline left ventricular dysfunction and suspected coronary disease who develop PEA should be evaluated for acute coronary occlusion.

Electroencephalographic and blood parameters changes in anaesthetised goats subjected to slaughter without stunning and slaughter following different electrical stunning methods

2019 ◽  
Vol 59 (5) ◽  
pp. 849
Author(s):  
A. B. Sabow ◽  
Y. M. Goh ◽  
I. Zulkifli ◽  
M. Z. Ab Kadir ◽  
U. Kaka ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Adverse Effects ◽  
Meat Quality ◽  
Tissue Damage ◽  
High Frequency ◽  
Sensory Input ◽  
Low Frequency ◽  
Blood Parameters ◽  
Brain Electrical Activity ◽  
High Frequencies

Electrical stunning is the most widely used stunning method for sheep and goats. Because low frequency head-to-back electrical stunning induces cardiac arrest, it is non-compliant with halal requirements. In addition, conventional head-only electrical stunning method can have adverse effects on carcass and meat quality. To address these issues high-frequency electrical stunning systems were developed. High frequency head-to-back removes the potential for pain and distress compared with non-stunned slaughter and does not induce cardiac arrest like low frequency head-to-back stunning making it appropriate for halal. However, this claim is yet to be proven through a comprehensive neurophysiological study. Thus, the present study examined the effects of different pre-slaughter electrical stunning methods and slaughter without stunning on electroencephalographic and blood biochemistry changes. Thirty-two male Boer crossbred bucks were distributed into four groups of eight animals each and subjected to slaughter without stunning (SWS), low frequency head-only (LFHO) and low frequency head-to-back (LFHB) or high frequency head-to-back electrical stunning (HFHB). Slaughtering of animals with or without stunning was performed under minimal anaesthesia. Based on electroencephalograph results, at slaughter, the SWS animals showed an increase in brain electrical activity, which is consistent with the presence of post slaughter noxious sensory input associated with tissue damage. Meanwhile the electroencephalograph activities decreased immediately after application of electrical stunning in all animals, suggesting that they were insensible to pain during and after the neck cut. Electrical brain activities for goats subjected to HFHB were comparable to those for LFHO and those for LFHB. The percentage of animals that exhibited severe clonic activity was significantly lower after LFHB or HFHB stunning compared with LFHO. The concentrations of catecholamines and hyperglycemia in electrically stunned goats were higher compared with those from SWS. It was observed that LFHB caused cardiac arrest in all goats whereas all HFHB goats had no cardiac arrest. High frequency head-to-back electrical stunning may be an improvement on non-stunned slaughter and has advantages for meat quality. However, stunning effectiveness after head-to-back electrical stunning with high frequencies needs to be evaluated under industrial conditions before any recommendation is given.

Comparison of the efficiency of rat papillary muscles during afterloaded isotonic contractions and contractions with sinusoidal length changes

2001 ◽  
Vol 204 (10) ◽  
pp. 1765-1774 ◽  
Author(s):  
L.J. Mellors ◽  
C.L. Gibbs ◽  
C.J. Barclay
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Length Change ◽  
Mechanical Efficiency ◽  
Left Ventricular ◽  
Maximum Efficiency ◽  
Papillary Muscles ◽  
Work Output ◽  
Length Changes ◽  
Isotonic Contractions

The results of previous studies suggest that the maximum mechanical efficiency of rat papillary muscles is lower during a contraction protocol involving sinusoidal length changes than during one involving afterloaded isotonic contractions. The aim of this study was to compare directly the efficiency of isolated rat papillary muscle preparations in isotonic and sinusoidal contraction protocols. Experiments were performed in vitro (27 degrees C) using left ventricular papillary muscles from adult rats. Each preparation performed three contraction protocols: (i) low-frequency afterloaded isotonic contractions (10 twitches at 0.2 Hz), (ii) sinusoidal length change contractions with phasic stimulation (40 twitches at 2 Hz) and (iii) high-frequency afterloaded isotonic contractions (40 twitches at 2 Hz). The first two protocols resembled those used in previous studies and the third combined the characteristics of the first two. The parameters for each protocol were adjusted to those that gave maximum efficiency. For the afterloaded isotonic protocols, the afterload was set to 0.3 of the maximum developed force. The sinusoidal length change protocol incorporated a cycle amplitude of +/−5 % resting length and a stimulus phase of −10 degrees. Measurements of force output, muscle length change and muscle temperature change were used to calculate the work and heat produced during and after each protocol. Net mechanical efficiency was defined as the proportion of the energy (enthalpy) liberated by the muscle that appeared as work. The efficiency in the low-frequency, isotonic contraction protocol was 21.1+/−1.4 % (mean +/− s.e.m., N=6) and that in the sinusoidal protocol was 13.2+/−0.7 %, consistent with previous results. This difference was not due to the higher frequency or greater number of twitches because efficiency in the high-frequency, isotonic protocol was 21.5+/−1.0 %. Although these results apparently confirm that efficiency is protocol-dependent, additional experiments designed to measure work output unambiguously indicated that the method used to calculate work output in isotonic contractions overestimated actual work output. When net work output, which excludes work done by parallel elastic elements, rather than total work output was used to determine efficiency in afterloaded isotonic contractions, efficiency was similar to that for sinusoidal contractions. The maximum net mechanical efficiency of rat papillary muscles performing afterloaded isotonic or sinusoidal length change contractions was between 10 and 15 %.

Cardiac Arrest And Resuscitation

2018 ◽  
Author(s):  
Patrick Hughes ◽  
Oren Mechanic ◽  
Shamai A. Grossman
Keyword(s):  
Cardiac Arrest ◽  
Life Support ◽  
Pulseless Electrical Activity ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Neurologic Recovery ◽  
End Tidal ◽  
Special Circumstances

The ultimate goal of cardiac resuscitation is full neurologic recovery; however, the probability of achieving this goal deteriorates rapidly with each minute of cardiac arrest. The most essential steps are rapid recognition of cardiac arrest, early high-quality chest compressions with minimal interruptions, and early defibrillation. Additional key components include effective leadership and followership, appropriate airway management, and effectual investigation for possible reversible causes of the arrest. This review discusses the role of and evidence for using pharmacologic agents. Additional discussion evaluates the use of ultrasonography and end-tidal CO2 in cardiac arrest resuscitation. Lastly, this review discusses cardiac arrest in special circumstances, such as patients who are pregnant, have left ventricular assist devices, or are subjects of trauma. This review contains 6 figures, 3 tables and 101 references Key words: advanced cardiovascular life support, antidysrhythmics, asystole, cardiac arrest, basic life support, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, pulseless electrical activity, resuscitation, ventricular fibrillation, ventricular tachycardia

Cardiac Arrest And Resuscitation

2020 ◽  
Author(s):  
Patrick Hughes ◽  
Oren Mechanic ◽  
Shamai A. Grossman
Keyword(s):  
Cardiac Arrest ◽  
Life Support ◽  
Pulseless Electrical Activity ◽  
Left Ventricular ◽  
Ventricular Assist Devices ◽  
Left Ventricular Assist Devices ◽  
Ventricular Assist ◽  
Neurologic Recovery ◽  
End Tidal ◽  
Special Circumstances

The ultimate goal of cardiac resuscitation is full neurologic recovery; however, the probability of achieving this goal deteriorates rapidly with each minute of cardiac arrest. The most essential steps are rapid recognition of cardiac arrest, early high-quality chest compressions with minimal interruptions, and early defibrillation. Additional key components include effective leadership and followership, appropriate airway management, and effectual investigation for possible reversible causes of the arrest. This review discusses the role of and evidence for using pharmacologic agents. Additional discussion evaluates the use of ultrasonography and end-tidal CO2 in cardiac arrest resuscitation. Lastly, this review discusses cardiac arrest in special circumstances, such as patients who are pregnant, have left ventricular assist devices, or are subjects of trauma. This review contains 6 figures, 4 tables and 102 references. Key words: advanced cardiovascular life support, antidysrhythmics, asystole, cardiac arrest, basic life support, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, pulseless electrical activity, resuscitation, ventricular fibrillation, ventricular tachycardia

Abstract 2629: High Dose Erythropoietin Improves the Postresuscitation Myocardial Dysfunction and Survival in an Appropriate Therapeutic Time Window

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Chien-Hua Huang ◽  
Chiung-Yuan Hsu ◽  
Huei-Wen Chen ◽  
Wei-Tien Chang ◽  
Wen-Jone Chen
Keyword(s):  
Cardiac Arrest ◽  
Time Window ◽  
Myocardial Dysfunction ◽  
Treated Group ◽  
Left Ventricular ◽  
Control Group ◽  
Male Adult ◽  
Term Survival ◽  
Therapeutic Time Window ◽  
Induced Cardiac Arrest

Introduction: The myocardial dysfunction carries high mortality rate in the postresuscitation period. Interventions for improving myocardial dysfunction may improve the outcomes of resuscitated victims. The erythropoietin (EPO) provides protective effects for the myocardium with ischemia-reperfusion injuries. However, its effects on the treatment of cardiopulmonary arrest and post-resuscitation myocardial dysfunction remain unknown. Hypothesis: EPO can improve the postresuscitation myocardial dysfunction in an appropriate therapeutic time window. Methods: Asphyxia-induced cardiac arrest was performed in male adult Wistar rats. Cardiopulmonary resuscitation including chest compressions, mechanical ventilation and epinephrine (0.01 mg/kg) was begun after 6.5 or 9.5 minutes of asphyxia. Animals were randomized to undergo treatment with intravenous EPO (5000 U/kg) or equivalent volume of 0.9% saline placebo. These agents were administrated 3 minutes after the return of spontaneous circulation. Results: The better left ventricular dP/dt 40 (2958±827 vs. 1321±1200 mmHg/s, P<0.05) and maximal -dP/dt (2562±546 vs. 745±877 mmHg/s, P<0.05) at 120 minutes after cardiac arrest, and better left ventricular fraction shortening (32.0 ± 2.0 vs. 24 ± 6.7 %, P<0.05) by echocardiography at 90 minutes after cardiac arrest were noted in the EPO-treated group compared to the control group in the condition of 6.5 minutes of asphyxia. The EPO treated group had better neurological recovery at 24 hours after resuscitation. Survival rate at 72 hours after 6.5 minutes of asphyxia was better in the EPO-treated group (50% vs. 20 %, P=0.02). No animal survived 72 hours after 9.5 minutes of asphyxia either in EPO-treated or control group. More activation of cardiac Akt and ERK 42/44 signaling pathways were noted in the EPO-treated group than the control group. Conclusions: EPO has the potential to improve postresuscitation myocardial dysfunction and short term survival in rats after asphyxia-induced cardiac arrest in an appropriate therapeutic time window.

scholarly journals Cardiac arrest in takotsubo syndrome: results from the InterTAK Registry

2019 ◽  
Vol 40 (26) ◽  
pp. 2142-2151 ◽  
Author(s):  
Sebastiano Gili ◽  
Victoria L Cammann ◽  
Susanne A Schlossbauer ◽  
Ken Kato ◽  
Fabrizio D’Ascenzo ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Acute Phase ◽  
Pulseless Electrical Activity ◽  
Heart Rhythm ◽  
Female Gender ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Takotsubo Syndrome ◽  
Ventricular Ejection Fraction ◽  
St Segment Elevation

Abstract Aims We aimed to evaluate the frequency, clinical features, and prognostic implications of cardiac arrest (CA) in takotsubo syndrome (TTS). Methods and results We reviewed the records of patients with CA and known heart rhythm from the International Takotsubo Registry. The main outcomes were 60-day and 5-year mortality. In addition, predictors of mortality and predictors of CA during the acute TTS phase were assessed. Of 2098 patients, 103 patients with CA and known heart rhythm during CA were included. Compared with patients without CA, CA patients were more likely to be younger, male, and have apical TTS, atrial fibrillation (AF), neurologic comorbidities, physical triggers, and longer corrected QT-interval and lower left ventricular ejection fraction on admission. In all, 57.1% of patients with CA at admission had ventricular fibrillation/tachycardia, while 73.7% of patients with CA in the acute phase had asystole/pulseless electrical activity. Patients with CA showed higher 60-day (40.3% vs. 4.0%, P < 0.001) and 5-year mortality (68.9% vs. 16.7%, P < 0.001) than patients without CA. T-wave inversion and intracranial haemorrhage were independently associated with higher 60-day mortality after CA, whereas female gender was associated with lower 60-day mortality. In the acute phase, CA occurred less frequently in females and more frequently in patients with AF, ST-segment elevation, and higher C-reactive protein on admission. Conclusions Cardiac arrest is relatively frequent in TTS and is associated with higher short- and long-term mortality. Clinical and electrocardiographic parameters independently predicted mortality after CA.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

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