Myocardial dysfunction after resuscitation from cardiac arrest: an example of global myocardial stunning

Effect of dimethyl fumarate on mitochondrial metabolism in a pediatric porcine model of asphyxia-induced in-hospital cardiac arrest

Neurological and cardiac injuries are significant contributors to morbidity and mortality following pediatric in-hospital cardiac arrest (IHCA). Preservation of mitochondrial function may be critical for reducing these injuries. Dimethyl fumarate (DMF) has shown potential to enhance mitochondrial content and reduce oxidative damage. To investigate the efficacy of DMF in mitigating mitochondrial injury in a pediatric porcine model of IHCA, toddler-aged piglets were subjected to asphyxia-induced CA, followed by ventricular fibrillation, high-quality cardiopulmonary resuscitation, and random assignment to receive either DMF (30 mg/kg) or placebo for four days. Sham animals underwent similar anesthesia protocols without CA. After four days, tissues were analyzed for mitochondrial markers. In the brain, untreated CA animals exhibited a reduced expression of proteins of the oxidative phosphorylation system (CI, CIV, CV) and decreased mitochondrial respiration (p < 0.001). Despite alterations in mitochondrial content and morphology in the myocardium, as assessed per transmission electron microscopy, mitochondrial function was unchanged. DMF treatment counteracted 25% of the proteomic changes induced by CA in the brain, and preserved mitochondrial structure in the myocardium. DMF demonstrates a potential therapeutic benefit in preserving mitochondrial integrity following asphyxia-induced IHCA. Further investigation is warranted to fully elucidate DMF's protective mechanisms and optimize its therapeutic application in post-arrest care.

Cumulative epinephrine dose during cardiac arrest and neurologic outcome after extracorporeal cardiopulmonary resuscitation

BACKGROUND

Epinephrine is recommended without an apparent ceiling dosage during cardiac arrest. However, excessive alpha- and beta-adrenergic stimulation may contribute to unnecessarily high aortic afterload, promote post-arrest myocardial dysfunction, and result in cerebral microvascular insufficiency in patients receiving extracorporeal cardiopulmonary resuscitation (ECPR).

METHODS

This was a retrospective cohort study of adults (≥ 18 years) who received ECPR at large academic ECMO center from 2018 to 2022. Patients were grouped based on the amount of epinephrine given during cardiac arrest into low (≤ 3 mg) and high (> 3 mg) groups. The primary endpoint was neurologic outcome at hospital discharge, defined by cerebral performance category (CPC). Multivariable logistic regression was used to assess the relationship between cumulative epinephrine dosage during arrest and neurologic outcome.

RESULTS

Among 51 included ECPR cases, the median age of patients was 60 years, and 55% were male. The mean cumulative epinephrine dose administered during arrest was 6.2 mg but ranged from 0 to 24 mg. There were 18 patients in the low-dose (≤ 3 mg) and 25 patients in the high-dose (> 3 mg) epinephrine groups. Favorable neurologic outcome at discharge was significantly greater in the low-dose (55%) compared to the high-dose (24%) group (p = 0.025). After adjusting for age, those who received higher doses of epinephrine during the arrest were more likely to have unfavorable neurologic outcomes at hospital discharge (odds ratio 4.6, 95% CI 1.3, 18.0, p = 0.017).

CONCLUSION

After adjusting for age, cumulative epinephrine doses above 3 mg during cardiac arrest may be associated with unfavorable neurologic outcomes after ECPR and require further investigation.

Survival, but not the severity of hypoxic-ischemic encephalopathy, is associated with higher mean arterial blood pressure after cardiac arrest: a retrospective cohort study

Background

This study investigates the association between the mean arterial blood pressure (MAP), vasopressor requirement, and severity of hypoxic-ischemic encephalopathy (HIE) after cardiac arrest (CA).

Methods

Between 2008 and 2017, we retrospectively analyzed the MAP 200 h after CA and quantified the vasopressor requirements using the cumulative vasopressor index (CVI). Through a postmortem brain autopsy in non-survivors, the severity of the HIE was histopathologically dichotomized into no/mild and severe HIE. In survivors, we dichotomized the severity of HIE into no/mild cerebral performance category (CPC) 1 and severe HIE (CPC 4). We investigated the regain of consciousness, causes of death, and 5-day survival as hemodynamic confounders.

Results

Among the 350 non-survivors, 117 had histopathologically severe HIE while 233 had no/mild HIE, without differences observed in the MAP (73.1 vs. 72.0 mmHg, pgroup = 0.639). Compared to the non-survivors, 211 patients with CPC 1 and 57 patients with CPC 4 had higher MAP values that showed significant, but clinically non-relevant, MAP differences (81.2 vs. 82.3 mmHg, pgroup < 0.001). The no/mild HIE non-survivors (n = 54), who regained consciousness before death, had higher MAP values compared to those with no/mild HIE (n = 179), who remained persistently comatose (74.7 vs. 69.3 mmHg, pgroup < 0.001). The no/mild HIE non-survivors, who regained consciousness, required fewer vasopressors (CVI 2.1 vs. 3.6, pgroup < 0.001). Independent of the severity of HIE, the survivors were weaned faster from vasopressors (CVI 1.0).

Conclusions

Although a higher MAP was associated with survival in CA patients treated with a vasopressor-supported MAP target above 65 mmHg, the severity of HIE was not. Awakening from coma was associated with less vasopressor requirements. Our results provide no evidence for a MAP target above the current guideline recommendations that can decrease the severity of HIE.

Severe trauma associated cardiac failure

Although significant efforts have been made to enhance trauma care, the mortality rate for traumatic cardiac arrest (TCA) remains exceedingly high. Therefore, our institution has implemented special measures to optimize the treatment of major trauma patients. These measures include a prehospital Medical Intervention Car (MIC) and a 'code red' protocol in the trauma resuscitation room for patients with TCA or shock. These measures enable the early treatment of reversible causes of TCA and have resulted in a significant number of patients achieving adequate ROSC. However, a significant proportion of these patients still die due to circulatory failure shortly after. Our observations from patients who underwent clamshell thoracotomy or received echocardiographic evaluation in conjunction with current scientific findings led us to conclude that dysfunction of the heart itself may be the cause. Therefore, we propose discussing severe trauma-associated cardiac failure (STAC) as a new entity to facilitate scientific research and the development of specific treatment strategies, with the aim of improving the outcome of severe trauma.

Post-cardiac arrest temporal evolution of left ventricular function in a rat model: speckle-tracking echocardiography and cardiac circulating biomarkers

Aims

There is little information from experimental studies regarding the evolution of post-resuscitation cardiac arrest [post-return of spontaneous circulation (post-ROSC)] myocardial dysfunction during mid-term follow-up. For this purpose, we assessed left ventricular (LV) function and circulating cardiac biomarkers at different time points in a rat model of cardiac arrest (CA).

Methods and results

Rats were divided into two groups: control and post-ROSC rats. Eight minutes of untreated ventricular fibrillation were followed by 8 min of cardiopulmonary resuscitation. Conventional and speckle-tracking echocardiographic (STE) parameters and cardiac circulating biomarkers concentrations were assessed, at 3, 4, 72, and 96 h post-ROSC. At 3 and 4 h post-ROSC, LV systolic function was severely impaired, and high-sensitivity cardiac troponin T and N-terminal pro-atrial natriuretic peptide (NT-proANP) plasma concentrations were significantly increased, compared with control rats (P < 0.0001 for all). At 72 and 96 h post-ROSC, LV ejection fraction (LVEF) normalized. At 96 h, the following variables were significantly different from control rats: early trans-mitral peak velocity, 56.8 ± 3.1 vs. 87.8 ± 3.8 cm/s, P < 0.0001; late trans-mitral peak velocity, 50.6 ± 4.7 vs. 73.7 ± 4.2 cm/s, P < 0.0001; mean s' wave velocity, 4.6 ± 0.3 vs. 5.9 ± 0.3 cm/s, P < 0.0001, global longitudinal strain (GLS) -7.5 ± 0.5 and vs. -11 ± 1.2%, P < 0.01; GLS rate (GLSR) -0.9 ± 0.4 and -2.3 ± 0.2 1/s, P < 0.01; and NT-proANP concentration, 2.5 (0.2; 6.0) vs. 0.4 (0.01; 1.0) nmol/L, P < 0.01.

Conclusion

s' velocity, GLS, and GLSR indicated that LV systolic function was still impaired 96 h post-ROSC. These findings agree with NT-proANP concentrations, which continue to be high. Normalization of LVEF supports the use of STE for its greater sensitivity for monitoring post-CA cardiac function. Further investigations are needed to provide evidence of the post-ROSC LV diastolic function pattern.

Effect of AT1 receptor blockade on cardiovascular outcome after cardiac arrest: an experimental study in rats

Angiotensin II receptor 1(AT1) antagonists are beneficial in focal ischemia/reperfusion (I/R). However, in cases of global I/R, such as cardiac arrest (CA), AT1 blocker's potential benefits are still unknown. Wistar male rats were allocated into four groups: Control group (CG)-animals submitted to CA by ventricular fibrillation induced by direct electrical stimulation for 3 min, and anoxia for 5 min; Group AT1 (GAT1)-animals subjected to CA and treated with 0.2 mg/kg of candesartan diluted in dimethylsulfoxide (DMSO) (0.1%); Vehicle Group (VG): animals subjected to CA and treated with 0.2 ml/kg of DMSO and Sham group (SG)-animals submitted to surgical interventions, without CA. Cardiopulmonary resuscitation consisted of group medications, chest compressions, ventilation, epinephrine (20 mcg/kg) and defibrillation. The animals were observed up to 4 h after spontaneous circulation (ROSC) return, and survival rates, hemodynamic variables, histopathology, and markers of tissue injury were analyzed. GAT1 group had a higher rate of ROSC (62.5% vs. 42.1%, p < 0.0001), survival (100% vs. 62.5%, p = 0.027), lower incidence of arrhythmia after 10 min of ROSC (10% vs. 62.5%, p = 0.000), and lower neuronal and cardiac injury scores on histology evaluation (p = 0.025 and p = 0.0052, respectively) than GC group. The groups did not differ regarding CA duration, number of adrenaline doses, or number of defibrillations. AT1 receptor blockade with candesartan yielded higher rates of ROSC and survival, in addition to neuronal and myocardial protection.

Factors associated with circulatory death after out-of-hospital cardiac arrest: a population-based cluster analysis

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is a common cause of death. Early circulatory failure is the most common reason for death within the first 48 h. This study in intensive care unit (ICU) patients with OHCA was designed to identify and characterize clusters based on clinical features and to determine the frequency of death from refractory postresuscitation shock (RPRS) in each cluster.

METHODS

We retrospectively identified adults admitted alive to ICUs after OHCA in 2011-2018 and recorded in a prospective registry for the Paris region (France). We identified patient clusters by performing an unsupervised hierarchical cluster analysis (without mode of death among the variables) based on Utstein clinical and laboratory variables. For each cluster, we estimated the hazard ratio (HRs) for RPRS.

RESULTS

Of the 4445 included patients, 1468 (33%) were discharged alive from the ICU and 2977 (67%) died in the ICU. We identified four clusters: initial shockable rhythm with short low-flow time (cluster 1), initial non-shockable rhythm with usual absence of ST-segment elevation (cluster 2), initial non-shockable rhythm with long no-flow time (cluster 3), and long low-flow time with high epinephrine dose (cluster 4). RPRS was significantly associated with this last cluster (HR, 5.51; 95% confidence interval 4.51-6.74).

CONCLUSIONS

We identified patient clusters based on Utstein criteria, and one cluster was strongly associated with RPRS. This result may help to make decisions about using specific treatments after OHCA.

Cardiac Arrest (CA) as the Initial Presentation of Cocaine-Induced Takotsubo Cardiomyopathy (TCM): A Case Report and Review of Literature

Cocaine is used as an illicit substance responsible for the most common cause of drug-related death. It is a stimulant that acts on the sympathetic nervous system and cardiovascular system leading to exaggerated, prolonged sympathetic activity due to the accumulation of neurotransmitters. Cardiovascular side effects of cocaine are coronary artery spasms, myocarditis, arrhythmias, and congestive heart failure. Takotsubo cardiomyopathy (TCM) is characterized by transient hypokinesis, akinesis, or dyskinesis of the left ventricle (LV) wall with or without apical involvement in the absence of obstructive coronary artery disease. Cocaine-induced TCM is an extremely rare condition emphasizing the need of its prompt diagnosis by the physicians. We present a case report of a 54-year-old male, brought to the emergency department (ED) after an out-of-hospital cardiac arrest (CA), found to have TCM in the setting of cocaine use. Clinicians need to understand the association between cocaine use and the development of TCM as cardiomyopathy of this type can result in complete remission after discontinuing the offending agent.

Bundle branch block in cardiac arrest survivors without ischemic heart disease

Aims

Cardiac arrest (CA) survivors with left/right bundle branch block (LBBB/RBBB) and no ischemic heart disease (IHD) have not been previously characterized. The aim of this study was to describe heart failure, implantable cardioverter defibrillator (ICD) therapy and mortality in this population.

Methods

Between 2009 and 2019 we consecutively identified all CA survivors with a consistent bundle branch block (BBB) defined as a QRS ≥ 120 ms, who had a secondary prophylactic ICD implanted. Patients with congenital and ischemic heart disease (IHD) were excluded.

Results

Among 701 CA-survivors who survived to discharge and received an ICD, a total of 58 (8%) were free from IHD and had BBB; 46 (79%) had LBBB, 10 (17%) had RBBB and 2 (3%) had non-specific BBB (NSBBB). The prevalence of LBBB was 7%. Pre-arrest ECG were available in 34 (59%) patients; 20 patients (59%) had LBBB, 6 (18%) had RBBB, 2 (6%) had NSBBB, 1 had (3%) incomplete LBBB, and 4 (12%) without BBB. At discharge, patients with LBBB had a significantly lower left ventricular ejection fraction (LVEF) than patients with other types of BBB, p < 0.001. During follow-up, 7 (12%) died after a median of 3.6 years (IQR: 2.6-5.1) with no difference between BBB subtypes.

Conclusion

We identified 58 CA-survivors with BBB and no IHD. The prevalence of LBBB among all CA-survivors was high, 7%. During CA hospitalization LBBB patients presented with a significantly lower LVEF than patients with other types of BBB (P < 0.001). ICD treatment and mortality did not differ between BBB subtypes during follow-up.

Clinical picture of the duration of venoarterial extracorporeal membrane oxygenation: analysis from JROAD-DPC

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has been widely used for critically ill patients all over the world; however, comprehensive survey regarding the relationship between VA-ECMO duration and prognosis is limited. We conducted a survey of VA-ECMO patients in the Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination (JROAD-DPC), which was a health insurance claim database study among cardiovascular centers associated with the Japan Circulation Society, between April 2012 and March 2016. Out of 13,542 VA-ECMO patients, we analyzed 5766 cardiovascular patients treated with VA-ECMO. 68% patients used VA-ECMO only for 1 day and 93% had VA-ECMO terminated within 1 week. In multivariate analysis, the hazard ratio of 1-day support was significantly high at 1.72 (95% confidence intervals; 95% CI 1.53-1.95) (p < 0.001), while that of 2-day [0.60 (95% CI 0.49-0.73)], 3-day [0.75 (95% CI 0.60-0.94)], 4-day [0.43 (95% CI 0.31-0.60)] and 5-day support [0.62 (95% CI 0.44-0.86)] was significantly low. Comprehensive database analysis of JROAD-DPC revealed that cardiovascular patients who were supported with VA-ECMO for 2-5 days showed lower mortality. The optimal VA-ECMO support window should be investigated in further studies.

Post-Cardiac Arrest: Mechanisms, Management, and Future Perspectives

Cardiac arrest is an important public health issue, with a survival rate of approximately 15 to 22%. A great proportion of these deaths occur after resuscitation due to post-cardiac arrest syndrome, which is characterized by the ischemia-reperfusion injury that affects the role body. Understanding physiopathology is mandatory to discover new treatment strategies and obtain better results. Besides improvements in cardiopulmonary resuscitation maneuvers, the great increase in survival rates observed in recent decades is due to new approaches to post-cardiac arrest care. In this review, we will discuss physiopathology, etiologies, and post-resuscitation care, emphasizing targeted temperature management, early coronary angiography, and rehabilitation.

Absence of Significant Myocardial Injury following Elective Direct Current Cardioversion for Atrial Fibrillation

Background

Direct current (DC) cardioversion is used to terminate cardiac arrhythmias. Current guidelines list cardioversion as a cause of myocardial injury.

Objective

This study determined whether external DC cardioversion results in myocardial injury measured by serial changes in high-sensitivity cardiac troponin T (hs-cTnT) and high-sensitivity cardiac troponin I (hs-cTnI).

Methods

This was a prospective study of patients undergoing elective external DC cardioversion for atrial fibrillation. hs-cTnT and hs-cTnI were measured precardioversion and at least 6 hours postcardioversion. Myocardial injury was present when there were significant changes in both hs-cTnT and hs-cTnI.

Results

Ninety-eight subjects were analyzed. Median cumulative energy delivered was 121.9 (interquartile range [IQR] 102.2-302.7) J. Multiple cases 23 (23.5%) required 300 J or more. Maximum cumulative energy delivered was 2455.1 J. There were small significant changes in both hs-cTnT (median precardioversion 12 [IQR 7-19) ng/L], median postcardioversion 13 [IQR 8-21] ng/L; P < .001) and hs-cTnI (median precardioversion 5 [IQR 3-10) ng/L], median postcardioversion 7 [IQR 3.6-11) ng/L; P < .001). Results were similar in patients with high-energy shocks and did not vary based on precardioversion values. Only 2 (2%) cases met criteria for myocardial injury.

Conclusion

DC cardioversion resulted in a small but statistically significant changes in hs-cTnT and hs-cTnI in 2% of patients studied irrespective of shock energy. Patients with marked troponin elevations after elective cardioversion should be assessed for other causes of myocardial injury. It should not be assumed the myocardial injury was from the cardioversion.

State-of-the-Art Multimodality Imaging in Sudden Cardiac Arrest with Focus on Idiopathic Ventricular Fibrillation: A Review

Idiopathic ventricular fibrillation is a rare cause of sudden cardiac arrest and a diagnosis by exclusion. Unraveling the mechanism of ventricular fibrillation is important for targeted management, and potentially for initiating family screening. Sudden cardiac arrest survivors undergo extensive clinical testing, with a growing role for multimodality imaging, before diagnosing "idiopathic" ventricular fibrillation. Multimodality imaging, considered as using multiple imaging modalities as diagnostics, is important for revealing structural myocardial abnormalities in patients with cardiac arrest. This review focuses on combining imaging modalities (echocardiography, cardiac magnetic resonance and computed tomography) and the electrocardiographic characterization of sudden cardiac arrest survivors and discusses the surplus value of multimodality imaging in the diagnostic routing of these patients. We focus on novel insights obtained through electrostructural and/or electromechanical imaging in apparently idiopathic ventricular fibrillation patients, with special attention to non-invasive electrocardiographic imaging.

Hypothermia preconditioning improves cardiac contractility after cardiopulmonary resuscitation through AMPK-activated mitophagy

Hypothermia preconditioning (HPC) improves cardiac function after cardiac arrest, yet the mechanism is unclear. We hypothesized that HPC-activated adenosine monophosphate-activated protein kinase (AMPK) activity may be involved. Adult male Wistar rats were randomly divided into normothermia Control, HPC (cooling to 32-34°C for 30 min), and HPC + Compound C (Compound C 10 mg/kg was injected intraperitoneally 30 min before HPC group). The rats underwent 7 min of untreated ventricular fibrillation (VF) followed by cardiopulmonary resuscitation (CPR). Cardiac function and hemodynamic parameters were evaluated at 4 h after return of spontaneous circulation (ROSC). Survival status was determined 72 h after ROSC. Mechanistically, we further examined the AMPK-Unc-51 Like Autophagy Activating Kinase 1 (ULK1)-mitophagy pathway and autophagic flux in vivo and in vitro. Six of twelve rats in the Control group, 10 of 12 rats in the HPC group, and 7 of 12 rats in HPC + Compound C group were successfully resuscitated. The 72-h survival rates were 1 of 12 Control, 6 of 12 HPC, and 2 of 12 HPC + Compound C rats, respectively (P = 0.043). Rats in the HPC group demonstrated greater cardiac contractility and hemodynamic stability which were compromised by Compound C. Furthermore, HPC increased the protein levels of p-AMPKα and p-ULK1 and promoted the expression of mitochondrial autophagy-related genes. Compound C decreased the expression of mitochondrial autophagy-related genes and reduced autophagic flux. Consistent with the observations obtained in vivo, in vitro experiments in cultured neonatal rat cardiomyocytes (CMs) demonstrated that HPC attenuated simulated ischemia-reperfusion-induced CM death, accompanied by increased AMPK-ULK1-mitophagy pathway activity. These findings suggest that AMPK-ULK1-mitophagy pathway was activated by HPC and has a crucial role in cardioprotection during cardiac arrest. Manipulation of mitophagy by hypothermia may merit further investigation as a novel strategy to prevent cardiac ischemia-reperfusion injury.

Effects of Different Hypothermia on the Results of Cardiopulmonary Resuscitation in a Cardiac Arrest Rat Model

Objective

To investigate the optimal temperature of hypothermia treatment in rats with cardiac arrest caused by ventricular fibrillation (VF) after the return of spontaneous circulation (ROSC).

Methods

A total of forty-eight male Sprague-Dawley rats were induced by VF through the guidewire with a maximum of 5 mA current and untreated for 8 min. Cardiopulmonary resuscitation (CPR) was performed for 8 min followed by defibrillation (DF). Resuscitated rats were then randomized into the normothermia (37°C) group, milder (35°C) group, mild (33°C) group, or moderate (28°C) group. Hypothermia was immediately induced with surface cooling. The target temperature was maintained for 4 h before rewarming to 37 ± 0.5°C. Moreover, at the end of the 4 h, a rat in each group was randomly selected to be sacrificed for the cerebral cortex electron microscopy observation (n = 1). The other resuscitated animals were observed for up to 72 h after ROSC (n = 7). Left ventricular ejection fraction (LVEF) and left ventricular end diastolic volume (LVEDV) were measured. Survival time, survival rate, and neurological deficit score (NDS) were recorded for 72 h.

Results

During hypothermia, higher LVEF was observed in the hypothermia groups when compared with normothermia group (35°C vs. 37°C, p < 0.05, 33°C and 28°C vs. 37°C, p < 0.01). Among the hypothermia groups, LVEF was higher in the 28°C group than that of 35°C (p < 0.05). However, both the heart rate (HR) (p < 0.01) and LVEDV (28°C vs. 35°C, p < 0.01, 28°C vs. 37°C and 33°C, p < 0.05) were lowest in the 28°C group when compared with the other groups. There were no significant differences of LVEF and LVEDV between the group 35°C and 33°C (p > 0.05). After rewarming, the LVEF of 35°C group was higher than that of group 37°C, 33°C, and 28°C (35°C vs. 37°C and 28°C, p < 0.01, 35°C vs. 33°C, p < 0.05). Group 35°C and 33°C resulted in longer survival (p < 0.01), higher survival rate (p < 0.01), and lower NDS (35°C vs. 37°C and 28°C, p < 0.01, 33°C vs. 37°C and 28°C, p < 0.05) compared with the group 37°C and 28°C. The extent of damage to cerebral cortex cells in group of 35°C and 33°C was lighter than that in group of 37°C and 28°C. The 35°C group spent less time in the process of cooling and rewarming than the group 33°C and 28°C (p < 0.01).

Conclusions

An almost equal protective effect of milder hypothermia (35°C) and mild hypothermia (33°C) in cardiac arrest (CA) rats was achieved with more predominant effect than moderate hypothermia (28°C) and normothermia (37°C). More importantly, shorter time spent in cooling and rewarming was required in the 35°C group, indicating its potential clinical application. These findings support the possible use of milder hypothermia (35°C) as a therapeutic agent for postresuscitation.

Changes of Key Rate-Limiting Enzyme Activity in Glucose Metabolism After Cardiopulmonary Resuscitation

OBJECTIVES

To investigate the activity of key rate-limiting enzymes of glucose metabolism after restoration of spontaneous circulation (ROSC), to explore the potential pathophysiological mechanism of impaired myocardial energy metabolism after cardiopulmonary resuscitation (CPR).

METHODS

Twenty-one male Sprague-Dawley rats were randomized into three experimental groups assigned in accordance with different observation times after ROSC: Sham, instrumented rats without induced cardiac arrest or resuscitation; post-resuscitation (PR2 h); PR24 h. In these groups, CPR, including precordial compressions and synchronized mechanical ventilation, was initiated 6 min after asphyxia-induced cardiac arrest. Hearts were harvested after ROSC and samples were used to detect high-energy phosphate and glucose metabolic enzyme activity.

RESULTS

Compared with sham, the contents of phosphocreatine and adenosine triphosphate reduced in the PR2 h group, while remained unchanged in the PR24 h group. Activities of hexokinase and pyruvate kinase did not change after ROSC. Phosphofructokinase activity decreased only in the PR24 h group. Activities of pyruvate dehydrogenase and citrate synthase fell in PR2 h group and recovered in the PR24 h group. However, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase activities fell in the PR2 h group, but did not recover in the PR24 h group.

CONCLUSIONS

Lowered key rate-limiting enzymes activity in glucose metabolism resulted in impairment of energy production in the early stage of ROSC, but partially recovered in 24 h. This process has a role in the mechanism of impaired myocardial energy metabolism after CPR. This investigation might shed light on new strategies to treat post resuscitation myocardial dysfunction.

Effect of Time to Treatment With Antiarrhythmic Drugs on Return of Spontaneous Circulation in Shock-Refractory Out-of-Hospital Cardiac Arrest

Background

The effects of amiodarone and lidocaine on the return of spontaneous circulation (ROSC) in relation to time to treatment in patients with out‐of‐hospital cardiac arrest is not known. We conducted a post hoc analysis of the ROC ALPS (Resuscitation Outcomes Consortium Amiodarone, Lidocaine, Placebo) randomized controlled trial examining the association of time to treatment (drug or placebo) with ROSC at hospital arrival.

Methods and Results

In the trial, adults with nontraumatic out‐of‐hospital cardiac arrest with initial refractory ventricular fibrillation or pulseless ventricular tachycardia after at least 1 defibrillation were randomly assigned to receive amiodarone, lidocaine, or placebo. We used logistic regression to examine the association of time to treatment (911 call to study drug administration) with ROSC. An interaction term between treatment and time to treatment was included to determine the potential effect of time on treatment effects. Overall, 1112 (36.7%) patients had ROSC at hospital arrival (350 in the amiodarone arm, 396 in the lidocaine arm, and 366 in the placebo arm). The proportion of patients who had ROSC decreased as time to drug administration increased, in patients treated with amiodarone (odds ratio, 0.92; 95% CI, 0.90–0.94 per minute increase), lidocaine (odds ratio, 0.95; 95% CI, 0.93–0.96), and placebo (odds ratio, 0.95; 95% CI, 0.93–0.96). With shorter times to drug administration, the proportion with ROSC was higher in amiodarone versus placebo recipients.

Conclusions

The probability of ROSC decreased as time to drug administration increased. The effect of amiodarone but not lidocaine to restore ROSC declined with longer times to drug administration, potentially attributable to its adverse hemodynamic effects.

Omecamtiv mecarbil treatment improves post-resuscitation cardiac function and neurological outcome in a rat model

Background

Myocardial dysfunction is a major cause of poor outcomes in the post-cardiac arrest period. Omecamtiv mecarbil (OM) is a selective small molecule activator of cardiac myosin that prolongs myocardial systole and increases stroke volume without apparent effects on myocardial oxygen demand. OM administration is safe and improves cardiac function in patients with acute heart failure. Whether OM improves post-resuscitation myocardial dysfunction remains unclear. This study investigated the effect of OM treatment on post-resuscitation myocardial dysfunction and outcomes.

Methods and results

Adult male rats were resuscitated after 9.5 min of asphyxia-induced cardiac arrest. OM and normal saline was continuously intravenously infused after return of spontaneous circulation (ROSC) at 0.25 mg/kg/h for 4 h in the experimental group and control group, respectively (n = 20 in each group). Hemodynamic parameters were measured hourly and monitored for 4 h after cardiac arrest. Recovery of neurological function was evaluated by neurological functioning scores (0–12; favorable: 11–12) for rats 72 h after cardiac arrest. OM treatment prolonged left ventricular ejection time and improved post-resuscitation cardiac output. Post-resuscitation heart rate and left ventricular systolic function (dp/dt₄₀) were not different between groups. Kaplan-Meier analysis showed non-statistically higher 72-h survival in the OM group (72.2% [13/18] and 58.8% [10/17], p = 0.386). The OM group had a higher chance of having favorable neurological outcomes in surviving rats 72 h after cardiac arrest (84.6% [11/13] vs. 40% [4/10], p = 0.026). The percentage of damaged neurons was lower in the OM group in a histology study at 72 h after cardiac arrest (55.5±2.3% vs. 76.2±10.2%, p = 0.004).

Conclusions

OM treatment improved post-resuscitation myocardial dysfunction and neurological outcome in an animal model. These findings support further pre-clinical studies to improve outcomes in post-cardiac arrest care.

Epinephrine versus norepinephrine in cardiac arrest patients with post-resuscitation shock

PURPOSE

Whether epinephrine or norepinephrine is preferable as the continuous intravenous vasopressor used to treat post-resuscitation shock is unclear. We assessed outcomes of patients with post-resuscitation shock after out-of-hospital cardiac arrest according to whether the continuous intravenous vasopressor used was epinephrine or norepinephrine.

METHODS

We conducted an observational multicenter study of consecutive patients managed in 2011-2018 for post-resuscitation shock. The primary outcome was all-cause hospital mortality, and secondary outcomes were cardiovascular hospital mortality and unfavorable neurological outcome (Cerebral Performance Category 3-5). A multivariate regression analysis and a propensity score analysis were performed, as well as several sensitivity analyses.

RESULTS

Of the 766 patients included in five hospitals, 285 (37%) received epinephrine and 481 (63%) norepinephrine. All-cause hospital mortality was significantly higher in the epinephrine group (OR 2.6; 95%CI 1.4-4.7; P = 0.002). Cardiovascular hospital mortality was also higher with epinephrine (aOR 5.5; 95%CI 3.0-10.3; P < 0.001), as was the proportion of patients with CPC of 3-5 at hospital discharge. Sensitivity analyses produced consistent results. The analysis involving adjustment on a propensity score to control for confounders showed similar findings (aOR 2.1; 95%CI 1.1-4.0; P = 0.02).

CONCLUSION

Among patients with post-resuscitation shock after out-of-hospital cardiac arrest, use of epinephrine was associated with higher all-cause and cardiovascular-specific mortality, compared with norepinephrine infusion. Until additional data become available, intensivists may want to choose norepinephrine rather than epinephrine for the treatment of post-resuscitation shock after OHCA.

Clinical Significance of Early Echocardiographic Changes after Resuscitated Out-of-Hospital Cardiac Arrest

BACKGROUND

Left Ventricular Systolic Dysfunction (LVSD) is common after out-of-hospital cardiac arrest (OOHCA) and can manifest globally or regionally, although its clinical significance has not been robustly studied. This study evaluates the association between LVSD, extent of coronary artery disease (CAD) and outcome in those undergoing early echocardiography and coronary angiography after OOHCA.

METHODS

Trans-thoracic echocardiography (TTE) was performed in OOHCA patients on arrival to our centre between May 2012 and December 2017. Rates of cardiogenic shock and extent of CAD, respectively classified by SCAI grade and the SYNTAX score, were measured. The primary end-point was 12-month mortality.

RESULTS

From 398 patients in the King's Out of Hospital Cardiac Arrest Registry (KOCAR), 266 patients (median age 61 [53-71], 76% male) underwent both TTE and coronary angiography on arrival. 96 patients (36%) had significant LVSD (Left Ventricular Ejection Fraction [LVEF]<40%) and 139 (52.2%) patients had regional wall motion abnormalities (RWMAs). Patients with LVEF<40% had more SCAI grade C-E shock (65.3% vs. 34.5%, p<0.001) and higher 12-month mortality (55.2% vs 31.8%, p<0.001) which was more likely to be due to a cardiac aetiology (27.3% vs 5.3%, p<0.001). Patients with RWMAs had higher median SYNTAX scores (14.75 vs 7, p=0.001), culprit coronary lesions (83.5% vs. 45.3%, p <0.001) and lower 12-month mortality (29.5% vs 52%, p<0.001).

CONCLUSIONS

Patients with LVEF <40% at presentation have an increased mortality, driven by cardiac aetiology death, while the presence of RWMAs is associated with a higher rate of culprit coronary lesions, representing a potentially reversible cause of the arrest, and improved survival at 1 year.

Severe Myocardial Dysfunction after Non-Ischemic Cardiac Arrest: Effectiveness of Percutaneous Assist Devices

Introduction: Despite the improvements in standardized cardiopulmonary resuscitation, survival remains low, mainly due to initial myocardial dysfunction and hemodynamic instability. Our goal was to compare the efficacy of two left ventricular assist devices on resuscitation and hemodynamic supply in a porcine model of ventricular fibrillation (VF) cardiac arrest. Methods: Seventeen anaesthetized pigs had 12 min of untreated VF followed by 6 min of chest compression and boluses of epinephrine. Next, a first defibrillation was attempted and pigs were randomized to any of the three groups: control (n = 5), implantation of an percutaneous left ventricular assist device (Impella, n = 5) or extracorporeal membrane oxygenation (ECMO, n = 7). Hemodynamic and myocardial functions were evaluated invasively at baseline, at return of spontaneous circulation (ROSC), after 10–30–60–120–240 min post-resuscitation. The primary endpoint was the rate of ROSC. Results: Only one of 5 pigs in the control group, 5 of 5 pigs in the Impella group, and 5 of 7 pigs in the ECMO group had ROSC (p < 0.05). Left ventricular ejection fraction at 240 min post-resuscitation was 37.5 ± 6.2% in the ECMO group vs. 23 ± 3% in the Impella group (p = 0.06). No significant difference in hemodynamic parameters was observed between the two ventricular assist devices. Conclusion: Early mechanical circulatory support appeared to improve resuscitation rates in a shockable rhythm model of cardiac arrest. This approach appears promising and should be further evaluated.

Precision Cardiac Arrest Resuscitation Based on Etiology

Cardiac arrest results from a broad range of etiologies that can be broadly grouped as sudden and asphyxial. Animal studies point to differences in injury pathways invoked in the heart and brain that drive injury and outcome after these different forms of cardiac arrest. Present guidelines largely ignore etiology in their management recommendations. Existing clinical data reveal significant heterogeneity in the utility of presently employed resuscitation and postresuscitation strategies based on etiology. The development of future neuroprotective and cardioprotective therapies should also take etiology into consideration to optimize the chances for successful translation.

Effect of Inhaled Xenon on Cardiac Function in Comatose Survivors of Out-of-Hospital Cardiac Arrest-A Substudy of the Xenon in Combination With Hypothermia After Cardiac Arrest Trial

This explorative substudy aimed at determining the effect of inhaled xenon on left ventricular function by echocardiography in comatose survivors of out-of-hospital cardiac arrest.

DESIGN

A randomized two-group single-blinded phase 2 clinical drug trial.

SETTING

A multipurpose ICU in two university hospitals.

PATIENTS

Of the 110 randomized comatose survivors after out-of-hospital cardiac arrest with a shockable rhythm in the xenon in combination with hypothermia after cardiac arrest trial, 38 patients (24-76 yr old) with complete echocardiography were included in this study.

INTERVENTIONS

Patients were randomized to receive either inhaled xenon combined with hypothermia (33°C) for 24 hours or hypothermia treatment alone. Echocardiography was performed at hospital admission and 24 ± 4 hours after hypothermia.

MEASUREMENTS AND MAIN RESULTS

Left ventricular ejection fraction, myocardial longitudinal systolic strain, and diastolic function were analyzed blinded to treatment. There were 17 xenon and 21 control patients in whom echocardiography was completed. Clinical characteristics did not differ significantly between the groups. At admission, ejection fraction was similar in xenon and control patients (39% ± 10% vs 38% ± 11%; p = 0.711) but higher in xenon than control patients after hypothermia (50% ± 10% vs 42% ± 10%; p = 0.014). Global longitudinal systolic strain was similar in xenon and control patients at admission (-9.0% ± 3.8% vs -8.1% ± 3.6%; p = 0.555) but better in xenon than control patients after hypothermia (-14.4.0% ± 4.0% vs -10.5% ± 4.0%; p = 0.006). In patients with coronary artery disease, longitudinal strain improved in the nonischemic myocardial segments in xenon patients. There were no changes in diastolic function between the groups.

CONCLUSIONS

Among comatose survivors of a cardiac cause out-of-hospital cardiac arrest, inhaled xenon combined with hypothermia was associated with greater recovery of left ventricular systolic function in comparison with hypothermia alone.

Left ventricular function recovery after ST-elevation myocardial infarction: correlates and outcomes

BACKGROUND

Contemporary data on left ventricular function (LVF) recovery in patients with left ventricular dysfunction after ST-elevation myocardial infarction (STEMI) are scarce and to date, no comparison has been made with patients with a baseline normal LVF. This study examined predictors of LVF recovery and its relation to outcomes in STEMI.

METHODS

Patients presenting with STEMI between January 2010 and December 2016 were categorized in three groups after 3 months according to left ventricular ejection fraction (EF): (i) baseline normal LVF (EF ≥ 50% at baseline); (ii) recovered LVF (EF < 50% at baseline and ≥ 50% after 3 months); and (iii) reduced LVF (EF < 50% at baseline and after 3 months). Heart failure hospitalization, all-cause mortality and cardiovascular mortality were compared between the three groups.

RESULTS

Of 577 patients, 341 (59%) patients had a baseline normal LVF, 112 (19%) had a recovered LVF and 124 (22%) had a reduced LVF. Independent correlates of LVF recovery were higher baseline EF, lower peak troponin and cardiac arrest. After median 5.8 years, there was no difference in outcomes between patients with LVF recovery and baseline normal LVF. In contrast, even after multivariate adjustment, patients with persistently reduced LVF had a higher risk for heart failure hospitalization (HR 5.00; 95% CI 2.17-11.46) and all-cause mortality (HR 1.87; 95% CI 1.11-3.16).

CONCLUSION

In contemporary treated STEMI patients, prognosis is significantly worse in those with a persistently reduced LVF after 3 months, compared with patients with a baseline normal LVF and those with LVF recovery.

Feasibility and beneficial effects of an early goal directed therapy after cardiac arrest: evaluation by conductance method

Although beneficial effects of an early goal directed therapy (EGDT) after cardiac arrest and successful return of spontaneous circulation (ROSC) have been described, clinical implementation in this period seems rather difficult. The aim of the present study was to investigate the feasibility and the impact of EGDT on myocardial damage and function after cardiac resuscitation. A translational pig model which has been carefully adapted to the clinical setting was employed. After 8 min of cardiac arrest and successful ROSC, pigs were randomized to receive either EGDT (EGDT group) or therapy by random computer-controlled hemodynamic thresholds (noEGDT group). Therapeutic algorithms included blood gas analysis, conductance catheter method, thermodilution cardiac output and transesophageal echocardiography. Twenty-one animals achieved successful ROSC of which 13 pigs survived the whole experimental period and could be included into final analysis. cTnT and LDH concentrations were lower in the EGDT group without reaching statistical significance. Comparison of lactate concentrations between 1 and 8 h after ROSC exhibited a decrease to nearly baseline levels within the EGDT group (1 h vs 8 h: 7.9 vs. 1.7 mmol/l, P < 0.01), while in the noEGDT group lactate concentrations did not significantly decrease. The EGDT group revealed a higher initial need for fluids (P < 0.05) and less epinephrine administration (P < 0.05) post ROSC. Conductance method determined significant higher values for preload recruitable stroke work, ejection fraction and maximum rate of pressure change in the ventricle for the EGDT group. EGDT after cardiac arrest is associated with a significant decrease of lactate levels to nearly baseline and is able to improve systolic myocardial function. Although the results of our study suggest that implementation of an EGDT algorithm for post cardiac arrest care seems feasible, the impact and implementation of EGDT algorithms after cardiac arrest need to be further investigated.

Echocardiographic parameters during prolonged targeted temperature Management in out-of-hospital Cardiac Arrest Survivors to predict neurological outcome - a post-hoc analysis of the TTH48 trial

BACKGROUND

Transthoracic echocardiographic (TTE) indices of myocardial function among survivors of out-of-hospital cardiac arrest (OHCA) have been related to neurological outcome; however, results are inconsistent. We hypothesized that changes in average peak systolic mitral annular velocity (s') from 24 h (h) to 72 h following start of targeted temperature management (TTM) predict six-month neurological outcome in comatose OHCA survivors.

METHODS

We investigated the association between peak systolic velocity of the mitral plane (s') and six-month neurological outcome in a population of 99 patients from a randomised controlled trial comparing TTM at 33 ± 1 °C for 24 h (h) (n = 47) vs. 48 h (n = 52) following OHCA (TTH48-trial). TTE was conducted at 24 h, 48 h, and 72 h after reaching target temperature. The primary outcome was 180 days neurological outcome assessed by Cerebral Performance Category score (CPC180) and the primary TTE outcome measure was s'. Secondary outcome measures were left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), e', E/e' and tricuspid annular plane systolic excursion (TAPSE).

RESULTS

Across all three scan time points s' was not associated with neurological outcome (ORs: 24 h: 1.0 (95%CI: 0.7-1.4, p = 0.98), 48 h: 1.13 (95%CI: 0.9-1.4, p = 0.34), 72 h: 1.04 (95%CI: 0.8-1.4, p = 0.76)). LVEF, GLS, E/e', and TAPSE recorded on serial TTEs following OHCA were neither associated with nor did they predict CPC180. Estimated median e' at 48 h following TTM was 5.74 cm/s (95%CI: 5.27-6.22) in patients with good outcome (CPC180 1-2) vs. 4.95 cm/s (95%CI: 4.37-5.54) in patients with poor outcome (CPC180 3-5) (p = 0.04).

CONCLUSIONS

s' assessed on serial TTEs in comatose survivors of OHCA treated with TTM was not associated with CPC180. Our findings suggest that serial TTEs in the early post-resuscitation phase during TTM do not aid the prognostication of neurological outcome following OHCA.

TRIAL REGISTRATION

NCT02066753 . Registered 14 February 2014 - Retrospectively registered.

Biventricular Unloading with Impella and Venoarterial Extracorporeal Membrane Oxygenation in Severe Refractory Cardiogenic Shock: Implications from the Combined Use of the Devices and Prognostic Risk Factors of Survival

Since mechanical circulatory support (MCS) devices have become integral component in the therapy of refractory cardiogenic shock (RCS), we identified 67 patients in biventricular support with Impella and venoarterial Extracorporeal Membrane Oxygenation (VA-ECMO) for RCS between February 2013 and December 2019 and evaluated the risk factors of mortality in this setting. Mean age was 61.07 ± 10.7 and 54 (80.6%) patients were male. Main cause of RCS was acute myocardial infarction (AMI) (74.6%), while 44 (65.7%) were resuscitated prior to admission. The mean Simplified Acute Physiology Score II (SAPS II) and Sequential Organ Failure Assessment Score (SOFA) score on admission was 73.54 ± 16.03 and 12.25 ± 2.71, respectively, corresponding to an expected mortality of higher than 80%. Vasopressor doses and lactate levels were significantly decreased within 72 h on biventricular support (p < 0.05 for both). Overall, 17 (25.4%) patients were discharged to cardiac rehabilitation and 5 patients (7.5%) were bridged successfully to ventricular assist device implantation, leading to a total of 32.8% survival on hospital discharge. The 6-month survival was 31.3%. Lactate > 6 mmol/L, vasoactive score > 100 and pH < 7.26 on initiation of biventricular support, as well as Charlson comorbity index > 3 and prior resuscitation were independent predictors of survival. In conclusion, biventricular support with Impella and VA-ECMO in patients with RCS is feasible and efficient leading to a better survival than predicted through traditional risk scores, mainly via significant hemodynamic improvement and reduction in lactate levels.

Hemodynamic and metabolic recovery in acute myocardial infarction-related cardiogenic shock is more rapid among patients presenting with out-of-hospital cardiac arrest

Background

Most studies in acute myocardial infarction complicated by cardiogenic shock (AMICS) include patients presenting with and without out-of-hospital cardiac arrest (OHCA). The aim was to compare OHCA and non-OHCA AMICS patients in terms of hemodynamics, management in the intensive care unit (ICU) and outcome.

Methods

From a cohort corresponding to two thirds of the Danish population, all patients with AMICS admitted from 2010–2017 were individually identified through patient records.

Results

A total of 1716 AMICS patients were identified of which 723 (42%) presented with OHCA. A total of 1532 patients survived to ICU admission. At the time of ICU arrival, there were no differences between OHCA and non-OHCA AMICS patients in variables commonly used in the AMICS definition (mean arterial pressure (MAP) (72mmHg vs 70mmHg, p = 0.12), lactate (4.3mmol/L vs 4.0mmol/L, p = 0.09) and cardiac output (CO) (4.6L/min vs 4.4L/min, p = 0.30)) were observed. However, during the initial days of ICU treatment OHCA patients had a higher MAP despite a lower need for vasoactive drugs, higher CO, SVO2 and lactate clearance compared to non-OHCA patients (p<0.05 for all). In multivariable analysis outcome was similar but cause of death differed significantly with hypoxic brain injury being leading cause in OHCA and cardiac failure in non-OHCA AMICS patients.

Conclusion

OHCA and non-OHCA AMICS patients initially have comparable metabolic and hemodynamic profiles, but marked differences develop between the groups during the first days of ICU treatment. Thus, pooling of OHCA and non-OHCA patients as one clinical entity in studies should be done with caution.

Post-resuscitation shock: recent advances in pathophysiology and treatment

A post-resuscitation shock occurs in 50–70% of patients who had a cardiac arrest. It is an early and transient complication of the post-resuscitation phase, which frequently leads to multiple-organ failure and high mortality. The pathophysiology of post-resuscitation shock is complex and results from the whole-body ischemia–reperfusion process provoked by the sequence of circulatory arrest, resuscitation manoeuvers and return of spontaneous circulation, combining a myocardial dysfunction and sepsis features, such as vasoplegia, hypovolemia and endothelial dysfunction. Similarly to septic shock, the hemodynamic management of post-resuscitation shock is based on an early and aggressive hemodynamic management, including fluid administration, vasopressors and/or inotropes. Norepinephrine should be considered as the first-line vasopressor in order to avoid arrhythmogenic effects of other catecholamines and dobutamine is the most established inotrope in this situation. Importantly, the optimal mean arterial pressure target during the post-resuscitation shock still remains unknown and may probably vary according to patients. Mechanical circulatory support by extracorporeal membrane oxygenation can be necessary in the most severe patients, when the neurological prognosis is assumed to be favourable. Other symptomatic treatments include protective lung ventilation with a target of normoxia and normocapnia and targeted temperature management by avoiding the lowest temperature targets. Early coronary angiogram and coronary reperfusion must be considered in ST-elevation myocardial infarction (STEMI) patients with preserved neurological prognosis although the timing of coronary angiogram in non-STEMI patients is still a matter of debate. Further clinical research is needed in order to explore new therapeutic opportunities regarding inflammatory, hormonal and vascular dysfunction.

Extraordinary Delayed-Onset Negative Pressure Pulmonary Hemorrhage Resulting in Cardiac Arrest after General Anesthesia for Vocal Cord Polypectomy

Negative pressure pulmonary edema and hemorrhage are uncommon but potentially life-threatening complications associated with general anesthesia. Postoperative negative pressure pulmonary edema usually occurs immediately after surgery, and delayed-onset cases occurring more than 1 hour after surgery have rarely been reported. A 37-year-old woman with bronchial asthma underwent vocal cord polypectomy under general anesthesia in another hospital and experienced cardiac arrest due to a negative pressure pulmonary hemorrhage occurring 3 hours and 30 minutes after surgery. She was successfully treated with venoarterial extracorporeal membrane oxygenation and completely recovered without any complications. Extraordinary delayed-onset negative pressure pulmonary hemorrhage occurring more than three hours after surgery has rarely been reported. This case may indicate the need for more careful observation of patients following surgery.

Cardiac arrest in takotsubo syndrome: results from the InterTAK Registry

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.

Cardiac Arrest in the Cardiac Catheterization Laboratory: Combining Mechanical Chest Compressions and Percutaneous LV Assistance

OBJECTIVES

The aim of this study was to evaluate the optimal treatment approach for cardiac arrest (CA) occurring in the cardiac catheterization laboratory.

BACKGROUND

CA can occur in the cath lab during high-risk percutaneous coronary intervention. While attempting to correct the precipitating cause of CA, several options are available to maintain vital organ perfusion. These include manual chest compressions, mechanical chest compressions, or a percutaneous left ventricular assist device.

METHODS

Eighty swine (58 ± 10 kg) were studied. The left main or proximal left anterior descending artery was occluded. Ventricular fibrillation (VFCA) was induced and circulatory support was provided with 1 of 4 techniques: either manual chest compressions (frequently interrupted), mechanical chest compressions with a piston device (LUCAS-2), an Impella 2.5 L percutaneously placed LVAD, or the combination of mechanical chest compressions and the percutaneous left ventricular assist device. The study protocol included 12 min of left main coronary occlusion, reperfusion, with defibrillation attempted after 15 min of VFCA. Primary outcome was favorable neurological function (CPC 1 or 2) at 24 h, while secondary outcomes included return of spontaneous circulation and hemodynamics.

RESULTS

Manual chest compressions provided fewer neurologically intact surviving animals than the combination of a mechanical chest compressor and a percutaneous LVAD device (0% vs. 56%; p < 0.01), while no difference was found between the 2 mechanical approaches (28% vs. 35%: p = 0.75). Comparing integrated coronary perfusion pressure showed sequential improvement in hemodynamic support with mechanical devices (401 ± 230 vs. 1,337 ± 905 mm Hg/s; p = 0.06).

CONCLUSIONS

Combining 2 mechanical devices provided superior 24-h survival with favorable neurological recovery compared with manual compressions during moderate duration VFCA associated with an acute coronary occlusion in the animal catheterization laboratory.

Association Between Intravenous Fluid Resuscitation and Hospital Mortality in Post Cardiac Arrest Patients: A Retrospective Study

OBJECTIVE

To assess the role for intravenous fluid (IVF) resuscitation in the postarrest state. Primary outcome was survival to hospital discharge and 30-day mortality. Secondary outcomes were associations with amount of vasopressor use and mechanical ventilation days.

DESIGN

Retrospective study design.

SETTING

Single-center tertiary hospital in Philadelphia, Pennsylvania.

PATIENTS

All patients admitted to the intensive care unit between 2018 and 2019.

INTERVENTIONS

Patients were divided into two groups based on amount of IVF received within 24 h <30 mL/kg (restricted) and over 30 mL/kg (liberal).

MEASUREMENTS AND MAIN RESULTS

A total of 264 patients were included in the study, with 200 included in the restrictive (<30 mL/kg) group and 64 included in the liberal (>30 mg/kg) group. There was no difference in 30-day mortality between the two groups with 146 (73%) deaths in the restrictive groups and 44 (69%) deaths in the liberal group (P = 0.53). There was also no significant difference between those who survived to hospital discharge in the liberal and restrictive groups on Kaplan-Meier analysis (Log-rank = 1.476 P = 0.224). However, there was a significant difference between restrictive and liberal groups with the duration of mechanical ventilation (4 ± 6 days vs. 6 ± 9 days; P = 0.03) and in the rates of two or more vasopressor use (38% vs. 59%; P = 0.002). End-stage renal disease (ESRD) (OR = 2.39; P = 0.03) and volume of fluids in mL/kg/24 h (OR = 1.025; P < 0.0001) were independently associated with higher vasopressor need. Volume of fluid in mL/kg/24 h (P = 0.01), ESRD (P = 0.015), and chronic obstructive pulmonary disease (P = 0.04) were significantly associated with duration of mechanical ventilation, even after adjusting for demographic factors, comorbidities, and mortality.

CONCLUSIONS

A liberal strategy of IVF used in resuscitation after cardiac arrest is not associated with higher mortality. However, it predicts higher vasopressor use and duration of mechanical ventilation.

Salvianolic Acid B Improves Postresuscitation Myocardial and Cerebral Outcomes in a Murine Model of Cardiac Arrest: Involvement of Nrf2 Signaling Pathway

Survival and outcome of cardiac arrest (CA) are dismal despite improvements in cardiopulmonary resuscitation (CPR). Salvianolic acid B (Sal B), extracted from Salvia miltiorrhiza, has been investigated for its cardioprotective properties in cardiac remodeling and ischemic heart disease, but less is known about its role in CA. The aim of this study was to learn whether Sal B improves cardiac and neurologic outcomes after CA/CPR in mice. Female C57BL/6 mice were subjected to eight minutes of CA induced by an intravenous injection of potassium chloride (KCl), followed by CPR. After 30 seconds of CPR, mice were blindly randomized to receive either Sal B (20 mg/kg) or vehicle (normal saline) intravenously. Hemodynamic variables and indices of left ventricular function were determined before CA and within three hours after CPR, the early postresuscitation period. Sal B administration resulted in a remarkable decrease in the time required for the return of spontaneous circulation (ROSC) in animals that successfully resuscitated compared to the vehicle-treated mice. Myocardial performance, including cardiac output and left ventricular systolic (dp/dt_max) and diastolic (dp/dt_min) function, was clearly ameliorated within three hours of ROSC in the Sal B-treated mice. Moreover, Sal B inhibited CA/CPR-induced cardiomyocyte apoptosis and preserved mitochondrial morphology and function. Mechanistically, Sal B dramatically promoted Nrf2 nuclear translocation through the downregulation of Keap1, which resulted in the expression of antioxidant enzymes, including HO-1 and NQO1, thereby counteracted the oxidative damage in response to CA/CPR. The aforementioned antiapoptotic and antioxidant effects of Sal B were impaired in the setting of gene silencing of Nrf2 with siRNA in vitro model. These improvements were associated with better neurological function and increased survival rate (75% vs. 40%, p < 0.05) up to 72 hours postresuscitation. Our findings suggest that the administration of Sal B improved cardiac function and neurological outcomes in a murine model of CA via activating the Nrf2 antioxidant signaling pathway, which may represent a novel therapeutic strategy for the treatment of CA.

The Association of Extreme Tachycardia and Sustained Return of Spontaneous Circulation after Nontraumatic Out-of-Hospital Cardiac Arrest

Objective

Heart rate (HR), an essential vital sign that reflects hemodynamic stability, is influenced by myocardial oxygen demand, coronary blood flow, and myocardial performance. HR at the time of the return of spontaneous circulation (ROSC) could be influenced by the β1-adrenergic effect of the epinephrine administered during cardiopulmonary resuscitation (CPR), and its effect could be decreased in patients who have the failing heart. We aimed to investigate the association between HR at the time of ROSC and the outcomes of adult out-of-hospital cardiac arrest (OHCA) patients.

Methods

This study was a secondary analysis of a cardiac arrest registry from a single institution from January 2008 to July 2014. The OHCA patients who achieved ROSC at the emergency department (ED) were included, and HR was retrieved from an electrocardiogram or vital sign at the time of ROSC. The patients were categorized into four groups according to the HR (bradycardia (HR < 60), normal HR (60 ≤ HR ≤ 100), tachycardia (100 < HR < 150), and extreme tachycardia (HR ≥ 150)). The primary outcome was the rate of sustained ROSC and the secondary outcomes were the rate of one-month survival and six-month good neurologic outcome.

Results

A total of 330 patients were included. In the univariate logistic regression model, the rate of sustained ROSC increased by 17% as HR increased by every 10 beats per minute (bpm) (odds ratio (OR), 1.171; 95% confidence interval (CI), 1.077–1.274, p < 0.001). In the multivariate logistic regression model, extreme tachycardia was independently associated with a high probability of sustained ROSC compared to normal heart rate (OR, 15.96; 95% CI, 2.04–124.93, p=0.008).

Conclusion

Extreme tachycardia (HR ≥ 150) at the time of ROSC is independently associated with a high probability of sustained ROSC in nontraumatic adult OHCA patients.

Aldehyde Dehydrogenase 2 Protects Against Post-Cardiac Arrest Myocardial Dysfunction Through a Novel Mechanism of Suppressing Mitochondrial Reactive Oxygen Species Production

Post-cardiac arrest myocardial dysfunction significantly contributes to early mortality after the return of spontaneous circulation. However, no effective therapy is available now. Aldehyde dehydrogenase 2 (ALDH2) enzyme has been shown to protect the heart from aldehyde toxicity such as 4-hydroxy-2-nonenal (4-HNE) and oxidative stress. In this study, we evaluated the effect of enhanced activity or expression of ALDH2 on post-cardiac arrest myocardial dysfunction and survival in a rat cardiac arrest model. Furthermore, we elucidated the underlying mechanisms with a focus on mitochondrial reactive oxygen species (ROS) production in a cell hypoxia/reoxygenation model. A total of 126 rats were used for the ALDH2 activation or cardiac overexpression of ALDH2 studies. Randomization was done 10 min before the respective agonist injection or in vivo gene delivery. We showed that enhanced activity or expression of ALDH2 significantly improved contractile function of the left ventricle and survival rate in rats subjected to cardiac arrest-cardiopulmonary resuscitation procedure. Moreover, ALDH2 prevented cardiac arrest-induced cardiomyocyte death from apoptosis and mitochondrial damage. Mechanistically, 4-HNE, a representative substrate of ALDH2, was dominantly increased in the hypoxia/reoxygenation-exposed cardiomyocytes. Direct addition of 4-HNE led to significantly augmented succinate accumulation and mitochondrial ROS production. Through metabolizing 4-HNE, ALDH2 significantly inhibited mitochondrial ROS production. Our findings provide compelling evidence of the cardioprotective effects of ALDH2 and therapeutic targeting this enzyme would provide an important approach for treating post-cardiac arrest myocardial dysfunction.

Suppression of Superoxide-Hydrogen Peroxide Production at Site IQ of Mitochondrial Complex I Attenuates Myocardial Stunning and Improves Postcardiac Arrest Outcomes

OBJECTIVES

Cardiogenic shock following cardiopulmonary resuscitation for sudden cardiac arrest is common, occurring even in the absence of acute coronary artery occlusion, and contributes to high rates of postcardiopulmonary resuscitation mortality. The pathophysiology of this shock is unclear, and effective therapies for improving clinical outcomes are lacking.

DESIGN

Laboratory investigation.

SETTING

University laboratory.

SUBJECTS

C57BL/6 adult female mice.

INTERVENTIONS

Anesthetized and ventilated adult female C57BL/6 wild-type mice underwent a 4, 8, 12, or 16-minute potassium chloride-induced cardiac arrest followed by 90 seconds of cardiopulmonary resuscitation. Mice were then blindly randomized to a single IV injection of vehicle (phosphate-buffered saline) or suppressor of site IQ electron leak, an inhibitor of superoxide production by complex I of the mitochondrial electron transport chain. Suppressor of site IQ electron leak and vehicle were administered during cardiopulmonary resuscitation.

MEASUREMENTS AND MAIN RESULTS

Using a murine model of asystolic cardiac arrest, we discovered that duration of cardiac arrest prior to cardiopulmonary resuscitation determined postresuscitation success rates, degree of neurologic injury, and severity of myocardial dysfunction. Post-cardiopulmonary resuscitation cardiac dysfunction was not associated with myocardial necrosis, apoptosis, inflammation, or mitochondrial permeability transition pore opening. Furthermore, left ventricular function recovered within 72 hours of cardiopulmonary resuscitation, indicative of myocardial stunning. Postcardiopulmonary resuscitation, the myocardium exhibited increased reactive oxygen species and evidence of mitochondrial injury, specifically reperfusion-induced reactive oxygen species generation at electron transport chain complex I. Suppressor of site IQ electron leak, which inhibits complex I-dependent reactive oxygen species generation by suppression of site IQ electron leak, decreased myocardial reactive oxygen species generation and improved postcardiopulmonary resuscitation myocardial function, neurologic outcomes, and survival.

CONCLUSIONS

The severity of cardiogenic shock following asystolic cardiac arrest is dependent on the length of cardiac arrest prior to cardiopulmonary resuscitation and is mediated by myocardial stunning resulting from mitochondrial electron transport chain complex I dysfunction. A novel pharmacologic agent targeting this mechanism, suppressor of site IQ electron leak, represents a potential, practical therapy for improving sudden cardiac arrest resuscitation outcomes.

Enhanced external counterpulsation improves cardiac function in Beagles after cardiopulmonary resuscitation

The aim of this study was to investigate the influence of enhanced external counterpulsation (EECP) on the cardiac function of beagle dogs after prolonged ventricular fibrillation. Twenty-four adult male beagles were randomly divided into control and EECP groups. Ventricular fibrillation was induced in the animals for 12 min, followed by 2 min of cardiopulmonary resuscitation. They then received EECP therapy for 4 h (EECP group) or not (control group). The hemodynamics was monitored using the PiCCO2 system. Blood gas and hemorheology were assessed at baseline and at 1, 2, and 4 h after return of spontaneous circulation (ROSC). The myocardial blood flow (MBF) was quantified by ¹⁸F-flurpiridaz PET myocardial perfusion imaging at baseline and 4 h after ROSC. Survival time of the animals was recorded within 24 h. Ventricular fibrillation was successfully induced in all animals, and they achieved ROSC after cardiopulmonary resuscitation. Survival time of the control group was shorter than that of the EECP group [median of 8 h (min 8 h, max 21 h) vs median of 24 h (min 16 h, max 24 h) (Kaplan Meyer plot analysis, P=0.0152). EECP improved blood gas analysis findings and increased the coronary perfusion pressure and MBF value. EECP also improved the cardiac function of Beagles after ROSC in multiple aspects, significantly increased blood flow velocity, and decreased plasma viscosity, erythrocyte aggregation index, and hematocrit levels. EECP improved the hemodynamics of beagle dogs and increased MBF, subsequently improving cardiac function and ultimately improving the survival time of animals after ROSC.

The Impact of Emergency Interventions and Patient Characteristics on the Risk of Heart Failure in Patients with Nontraumatic OHCA

Background

Since out-of-hospital cardiac arrest- (OHCA-) related dysfunction (ischemic/reperfusion injury and inflammatory response) might result in long-term impairment, we suspect that new-onset heart failure might be common in long-term survivors. However, these relationships had not been well addressed, and we aimed to analyze the impact of emergency interventions and patient characteristics on the risk of new-onset heart failure in patients with nontraumatic OHCA.

Methods

The Taiwanese government healthcare database contains data for 49,101 nontraumatic OHCA adult patients from 2011-2012, which were analyzed in this study. Nontraumatic OHCA patients who survived to the intensive care unit (ICU) were included as the study group (n = 7,321). Matched patients (n = 21,963) were recruited as a comparison group. Patients with any history of heart failure or cardiac arrest were not included in either group. All patients were followed-up for 6 months for the identification of new-onset heart failure. Adjustments were made for demographics, age, emergency interventions, and comorbidities as potential risk factors.

Results

In all, 3.84% (n = 281) of OHCA patients suffered new-onset heart failure, while only 1.24% (n = 272) of matched patients in the comparison group suffered new-onset heart failure. Strong risk factors for heart failure were age (60-75 years, HR: 11.4; 95% CI: 9-14.4), medical history (myocardial infarction, HR: 2.47; 95% CI: 2.05-2.98 and cardiomyopathy, HR: 2.94; 95% CI: 1.45-5.94), and comorbidities during hospitalization (ischemic heart disease, HR: 4.5; 95% CI: 3.46-5.86). Only extracorporeal membrane oxygenation (ECMO) decreased the risk of heart failure. Most (53.6%) heart failure events occurred within 60 days after OHCA.

Conclusion

An age from 61 to 75 years, a history of myocardial infarction or cardiomyopathy, and ischemic heart disease or infection as comorbidities occurring during hospitalization were strong risk factors for new-onset heart failure in OHCA patients. However, ECMO could decrease this risk. More importantly, most heart failure events occurred within 60 days after OHCA.

Cardiac Shock Care Centers: JACC Review Topic of the Week

Despite advances over the past decade, the incidence of cardiogenic shock secondary to acute myocardial infarction has increased, with an unchanged mortality near 50%. Recent trials have not clarified the best strategies in treatment. While dedicated cardiac shock centers are being established, there are no standardized agreements on the utilization of mechanical circulatory support and the timeliness of percutaneous coronary intervention strategies. In some centers and prospective registries, outcomes after placement of advanced mechanical circulatory support prior to reperfusion therapy with percutaneous coronary intervention have been encouraging with improved survival. Here, we suggest systems of care with a treatment pathway for patients with acute myocardial infarction complicated by cardiogenic shock.

Optimizing the Early Resuscitation After Out-of-Hospital Cardiac Arrest

Resuscitation after out-of-hospital cardiac arrest can be one of the most challenging scenarios in acute-care medicine. The devastating effects of postcardiac arrest syndrome carry a substantial morbidity and mortality that persist long after return of spontaneous circulation. Management of these patients requires the clinician to simultaneously address multiple emergent priorities including the resuscitation of the patient and the efficient diagnosis and management of the underlying etiology. This review provides a concise evidence-based overview of the core concepts involved in the early postcardiac arrest resuscitation. It will highlight the components of an effective management strategy including addressing hemodynamic, oxygenation, and ventilation goals as well as carefully considering cardiac catheterization and targeted temperature management. An organized approach is paramount to providing effective care to patients in this vulnerable time period.

[Postcardiac arrest treatment guide]

BACKGROUND

Treatment after cardiac arrest has become more complex and interdisciplinary over the last few years. Thus, the clinically active intensive and emergency care physician not only has to carry out the immediate care and acute diagnostics, but also has to prognosticate the neurological outcome.

AIM

The different, most important steps are presented by leading experts in the area, taking into account the interdisciplinarity and the currently valid guidelines.

MATERIALS AND METHODS

Attention was paid to a concise, practice-oriented presentation.

RESULTS AND DISCUSSION

The practical guide contains all important steps from the acute care to the neurological prognosis generation that are relevant for the clinically active intensive care physician.

Intra-Arrest Administration of Cyclosporine and Methylprednisolone Does Not Reduce Postarrest Myocardial Dysfunction

Objective

To determine whether the administration of intra-arrest cyclosporine (CCY) and methylprednisolone (MP) preserves left ventricular ejection fraction (LVEF) and cardiac output (CO) after return of spontaneous circulation (ROSC).

Methods

Eleven, 25-30kg female swine were randomized to receive 10mg/kg CCY + 40mg MP or placebo, anesthetized and given a transthoracic shock to induce ventricular fibrillation. After 8 minutes, standard CPR was started. After two additional minutes, the experimental agent was administered. Animals with ROSC were supported for up to 12h with norepinephrine as needed. Echocardiography was performed at baseline, and 1, 2, 6 and 12h post-ROSC. Analysis was performed using generalized estimating equations (GEE) after downsampling continuously sampled data to 5 minute epochs.

Results

Eight animals (64%) achieved ROSC after a median of 7 [IQR 5-13] min of CPR, 2 [ IQR 1-3] doses of epinephrine and 2 [IQR 1-5] defibrillation shocks. Animals receiving CCY+MP had higher post ROSC MAP (GEE coefficient -10.2, P = <0.01), but reduced cardiac output (GEE coefficient 0.8, P = <0.01) compared to placebo. There was no difference in LVEF or vasopressor use between arms.

Conclusions

Intra-arrest cyclosporine and methylprednisolone decreased post-arrest cardiac output and increased mean arterial pressure without affecting left ventricular ejection fraction.

The association of immediate post cardiac arrest diastolic hypertension and survival following pediatric cardiac arrest

AIM

In-hospital cardiac arrest occurs in >5000 children each year in the US and almost half will not survive to discharge. Animal data demonstrate that an immediate post-resuscitation burst of hypertension is associated with improved survival. We aimed to determine if systolic and diastolic invasive arterial blood pressures immediately (0-20 min) after return of spontaneous circulation (ROSC) are associated with survival and neurologic outcomes at hospital discharge.

METHODS

This is a secondary analysis of the Pediatric Intensive Care Quality of CPR (PICqCPR) study of invasively measured blood pressures during intensive care unit CPR. Patients were eligible if they achieved ROSC and had at least one invasively measured blood pressure within the first 20 min following ROSC. Post-ROSC blood pressures were normalized for age, sex and height. "Immediate hypertension" was defined as at least one systolic or diastolic blood pressure >90th percentile. The primary outcome was survival to hospital discharge.

RESULTS

Of 102 children, 70 (68.6%) had at least one episode of immediate post-CPR diastolic hypertension. After controlling for pre-existing hypotension, duration of CPR, calcium administration, and first documented rhythm, patients with immediate post-CPR diastolic hypertension were more likely to survive to hospital discharge (79.3% vs. 54.5%; adjusted OR = 2.93; 95%CI, 1.16-7.69).

CONCLUSIONS

In this post hoc secondary analysis of the PICqCPR study, 68.6% of subjects had diastolic hypertension within 20 min of ROSC. Immediate post-ROSC hypertension was associated with increased odds of survival to discharge, even after adjusting for covariates of interest.

The association of early post-resuscitation hypotension with discharge survival following targeted temperature management for pediatric in-hospital cardiac arrest

AIM

Approximately 40% of children who have an in-hospital cardiac arrest (IHCA) in the US survive to discharge. We aimed to evaluate the impact of post-cardiac arrest hypotension during targeted temperature management following IHCA on survival to discharge.

METHODS

This is a secondary analysis of the therapeutic hypothermia after pediatric cardiac arrest in-hospital (THAPCA-IH) trial. "Early hypotension" was defined as a systolic blood pressure less than the fifth percentile for age and sex for patients not treated with extracorporeal membrane oxygenation (ECMO) or a mean arterial pressure less than fifth percentile for age and sex for patients treated with ECMO during the first 6 h of temperature intervention. The primary outcome was survival to hospital discharge.

RESULTS

Of 299 children, 142 (47%) patients did not receive ECMO and 157 (53%) received ECMO. Forty-two of 142 (29.6%) non-ECMO patients had systolic hypotension. Twenty-three of 157 (14.7%) ECMO patients had mean arterial hypotension. After controlling for confounders of interest, non-ECMO patients who had early systolic hypotension were less likely to survive to hospital discharge (40.5% vs. 72%; adjusted OR [aOR] 0.34; 95%CI, 0.12-0.93). There was no difference in survival to discharge by blood pressure groups for children treated with ECMO (30.4% vs. 49.3%; aOR = 0.60; 95%CI, 0.22-1.63).

CONCLUSIONS

In this secondary analysis of the THAPCA-IH trial, in patients not treated with ECMO, systolic hypotension within 6 h of temperature intervention was associated with lower odds of discharge survival. Blood pressure groups in patients treated with ECMO were not associated with survival to discharge.