Mental health sequelae in survivors of cardiogenic shock complicating myocardial infarction. A population-based cohort study.

PURPOSE: Cardiogenic shock secondary to acute myocardial infarction (AMI-CS) is associated with substantial short- and long-term morbidity and mortality. However, there are limited data on mental health sequelae that survivors experience following discharge. METHODS: We conducted a retrospective, population-based cohort study in Ontario, Canada of critically ill adult (≥ 18 years) survivors of AMI-CS, admitted to hospital between April 1, 2009 and March 31, 2019. We compared these patients to AMI survivors without shock. We captured outcome data using linked health administrative databases. The primary outcome was a new mental health diagnosis (a composite of mood, anxiety, or related disorders; schizophrenia/psychotic disorders; and other mental health disorders) following hospital discharge. We secondarily evaluated incidence of deliberate self-harm and death by suicide. We compared patients using overlap propensity score-weighted, cause-specific proportional hazard models. RESULTS: We included 7812 consecutive survivors of AMI-CS, from 135 centers. Mean age was 68.4 (standard deviation (SD) 12.2) years, and 70.3% were male. Median follow-up time was 767 days (interquartile range (IQR) 225-1682). Incidence of new mental health diagnosis among AMI-CS survivors was 109.6 per 1,000 person-years (95% confidence interval (CI) 105.4-113.9), compared with 103.8 per 1000 person-years (95% CI 102.5-105.2) among AMI survivors without shock. After propensity score adjustment, there was no difference in the risk of new mental health diagnoses following discharge [hazard ratio (HR) 0.99 (95% CI 0.94-1.03)]. Factors associated with new mental health diagnoses following AMI-CS included female sex, pre-existing mental health diagnoses, and discharge to a long-term hospital or rehabilitation institute. CONCLUSION: Survivors of AMI-CS experience substantial mental health morbidity following discharge. Risk of new mental health diagnoses was comparable between survivors of AMI with and without shock. Future research on interventions to mitigate psychiatric sequelae after AMI-CS is warranted.

Canadian Cardiovascular Society/Canadian Cardiovascular Critical Care Society/Canadian Association of Interventional Cardiology Clinical Practice Update on Optimal Post Cardiac Arrest and Refractory Cardiac Arrest Patient Care.

Survival to hospital discharge among patients with out-of-hospital cardiac arrest (OHCA) is low and important regional differences in treatment practices and survival have been described. Since the 2017 publication of the Canadian Cardiovascular Society's position statement on OHCA care, multiple randomized controlled trials have helped to better define optimal post cardiac arrest care. This working group provides updated guidance on the timing of cardiac catheterization in patients with ST-elevation and without ST-segment elevation, on a revised temperature control strategy targeting normothermia instead of hypothermia, blood pressure, oxygenation, and ventilation parameters, and on the treatment of rhythmic and periodic electroencephalography patterns in patients with a resuscitated OHCA. In addition, prehospital trials have helped craft new expert opinions on antiarrhythmic strategies (amiodarone or lidocaine) and outline the potential role for double sequential defibrillation in patients with refractory cardiac arrest when equipment and training is available. Finally, we advocate for regionalized OHCA care systems with admissions to a hospital capable of integrating their post OHCA care with comprehensive on-site cardiovascular services and provide guidance on the potential role of extracorporeal cardiopulmonary resuscitation in patients with refractory cardiac arrest. We believe that knowledge translation through national harmonization and adoption of contemporary best practices has the potential to improve survival and functional outcomes in the OHCA population.

Sphingolipids in Childhood Asthma and Obesity (SOAP Study): A Protocol of a Cross-Sectional Study.

Asthma and obesity are two of the most common chronic conditions in children and adolescents. There is increasing evidence that sphingolipid metabolism is altered in childhood asthma and is linked to airway hyperreactivity. Dysregulated sphingolipid metabolism is also reported in obesity. However, the functional link between sphingolipid metabolism, asthma, and obesity is not completely understood. This paper describes the protocol of an ongoing study on sphingolipids that aims to examine the pathophysiology of sphingolipids in childhood asthma and obesity. In addition, this study aims to explore the novel biomarkers through a comprehensive multi-omics approach including genomics, genome-wide DNA methylation, RNA-Seq, microRNA (miRNA) profiling, lipidomics, metabolomics, and cytokine profiling. This is a cross-sectional study aiming to recruit 440 children from different groups: children with asthma and normal weight (n = 100), asthma with overweight or obesity (n = 100), overweight or obesity (n = 100), normal weight (n = 70), and siblings of asthmatic children with normal weight, overweight, or obesity (n = 70). These participants will be recruited from the pediatric pulmonology, pediatric endocrinology, and general pediatric outpatient clinics at Sidra Medicine, Doha, Qatar. Information will be obtained from self-reported questionnaires on asthma, quality of life, food frequency (FFQ), and a 3-day food diary that are completed by the children and their parents. Clinical measurements will include anthropometry, blood pressure, biochemistry, bioelectrical impedance, and pulmonary function tests. Blood samples will be obtained for sphingolipid analysis, serine palmitoyltransferase (SPT) assay, whole-genome sequencing (WGS), genome-wide DNA methylation study, RNA-Seq, miRNA profiling, metabolomics, lipidomics, and cytokine analysis. Group comparisons of continuous outcome variables will be carried out by a one-way analysis of variance or the Kruskal-Wallis test using an appropriate pairwise multiple comparison test. The chi-squared test or a Fisher's exact test will be used to test the associations between categorical variables. Finally, multivariate analysis will be carried out to integrate the clinical data with multi-omics data. This study will help us to understand the role of dysregulated sphingolipid metabolism in obesity and asthma. In addition, the multi-omics data from the study will help to identify novel genetic and epigenetic signatures, inflammatory markers, and mechanistic pathways that link asthma and obesity in children. Furthermore, the integration of clinical and multi-omics data will help us to uncover the potential interactions between these diseases and to offer a new paradigm for the treatment of pediatric obesity-associated asthma.

Age and associated outcomes among patients receiving venoarterial extracorporeal membrane oxygenation-analysis of the Extracorporeal Life Support Organization registry.

PURPOSE: Venoarterial extracorporeal membrane oxygenation (V-A ECMO) can be used to support severely ill patients with cardiogenic shock. While age is commonly used in patient selection, little is known regarding its association with outcomes in this population. We sought to evaluate the association between increasing age and outcomes following V-A ECMO. METHODS: We used individual-level patient data from 440 centers in the international Extracorporeal Life Support Organization registry. We included all adult patients receiving V-A ECMO from 2017 to 2019. The primary outcome was hospital mortality. Secondary outcomes included a composite of complications following initiation of V-A ECMO. We conducted Bayesian analyses of the relationship between increasing age and outcomes of interest. RESULTS: We included 15,172 patients receiving V-A ECMO. Of these, 8172 (53.9%) died in hospital. For the analysis conducted using weakly informed priors, and as compared to the reference category of age 18-29, the age bracket of 30-39 (odds ratio [OR] 0.94, 95% credible interval [CrI] 0.79-1.10) was not associated with hospital mortality, but age brackets 40-49 (odds ratio [OR] 1.26, 95% CrI: 1.08-1.47), 50-59 (OR 1.78, 95% CrI: 1.55-2.06), 60-69 (OR 2.24, 95% CrI: 1.94-2.59), 70-79 (OR 2.90, 95% CrI: 2.49-3.39) and ≥ 80 (OR 4.02, 95% CrI: 3.13-5.20) were independently associated with increasing hospital mortality. Similar results were found in the analysis conducted with an informative prior, as well as between increasing age and post-ECMO complications. CONCLUSIONS: Among patients receiving V-A ECMO for cardiogenic shock, increasing age is strongly associated with increasing odds of death and complications, and this association emerges as early as 40 years of age.

Tumor-intrinsic metabolic reprogramming and how it drives resistance to anti-PD-1/PD-L1 treatment.

The development of immune checkpoint blockade (ICB) therapies has been instrumental in advancing the field of immunotherapy. Despite the prominence of these treatments, many patients exhibit primary or acquired resistance, rendering them ineffective. For example, anti-programmed cell death protein 1 (anti-PD-1)/anti-programmed cell death ligand 1 (anti-PD-L1) treatments are widely utilized across a range of cancer indications, but the response rate is only 10%-30%. As such, it is necessary for researchers to identify targets and develop drugs that can be used in combination with existing ICB therapies to overcome resistance. The intersection of cancer, metabolism, and the immune system has gained considerable traction in recent years as a way to comprehensively study the mechanisms that drive oncogenesis, immune evasion, and immunotherapy resistance. As a result, new research is continuously emerging in support of targeting metabolic pathways as an adjuvant to ICB to boost patient response and overcome resistance. Due to the plethora of studies in recent years highlighting this notion, this review will integrate the relevant articles that demonstrate how tumor-derived alterations in energy, amino acid, and lipid metabolism dysregulate anti-tumor immune responses and drive resistance to anti-PD-1/PD-L1 therapy.

The PTPN2/PTPN1 inhibitor ABBV-CLS-484 unleashes potent anti-tumour immunity.

Immune checkpoint blockade is effective for some patients with cancer, but most are refractory to current immunotherapies and new approaches are needed to overcome resistance1,2. The protein tyrosine phosphatases PTPN2 and PTPN1 are central regulators of inflammation, and their genetic deletion in either tumour cells or immune cells promotes anti-tumour immunity3-6. However, phosphatases are challenging drug targets; in particular, the active site has been considered undruggable. Here we present the discovery and characterization of ABBV-CLS-484 (AC484), a first-in-class, orally bioavailable, potent PTPN2 and PTPN1 active-site inhibitor. AC484 treatment in vitro amplifies the response to interferon and promotes the activation and function of several immune cell subsets. In mouse models of cancer resistant to PD-1 blockade, AC484 monotherapy generates potent anti-tumour immunity. We show that AC484 inflames the tumour microenvironment and promotes natural killer cell and CD8+ T cell function by enhancing JAK-STAT signalling and reducing T cell dysfunction. Inhibitors of PTPN2 and PTPN1 offer a promising new strategy for cancer immunotherapy and are currently being evaluated in patients with advanced solid tumours (ClinicalTrials.gov identifier NCT04777994 ). More broadly, our study shows that small-molecule inhibitors of key intracellular immune regulators can achieve efficacy comparable to or exceeding that of antibody-based immune checkpoint blockade in preclinical models. Finally, to our knowledge, AC484 represents the first active-site phosphatase inhibitor to enter clinical evaluation for cancer immunotherapy and may pave the way for additional therapeutics that target this important class of enzymes.

Long-Term Outcomes of Cardiogenic Shock Complicating Myocardial Infarction.

BACKGROUND: Cardiogenic shock secondary to acute myocardial infarction (AMI-CS) is associated with substantial short-term mortality; however, there are limited data on long-term outcomes and trends. OBJECTIVES: This study sought to examine long-term outcomes of AMI-CS patients. METHODS: This was a population-based, retrospective cohort study in Ontario, Canada of critically ill adult patients with AMI-CS who were admitted to hospitals between April 1, 2009 and March 31, 2019. Outcome data were captured using linked health administrative databases. RESULTS: A total of 9,789 consecutive patients with AMI-CS from 135 centers were included. The mean age was 70.5 ± 12.3 years, and 67.7% were male. The incidence of AMI-CS was 8.2 per 100,000 person-years, and it increased over the study period. Critical care interventions were common, with 5,422 (55.4%) undergoing invasive mechanical ventilation, 1,425 (14.6%) undergoing renal replacement therapy, and 1,484 (15.2%) receiving mechanical circulatory support. A total of 2,961 patients (30.2%) died in the hospital, and 4,004 (40.9%) died by 1 year. Mortality at 5 years was 58.9%. Small improvements in short- and long-term mortality were seen over the study period. Among survivors to discharge, 2,870 (42.0%) required increased support in care from their preadmission baseline, 3,244 (47.5%) were readmitted to the hospital within 1 year, and 1,047 (15.3%) died within 1 year. The mean number of days at home in the year following discharge was 307.9 ± 109.6. CONCLUSIONS: Short- and long-term mortality among patients with AMI-CS is high, with minimal improvement over time. AMI-CS survivors experience significant morbidity, with high risks of readmission and death. Future studies should evaluate interventions to minimize postdischarge morbidity and mortality among AMI-CS survivors.

Efficacy of Milrinone and Dobutamine in Cardiogenic Shock: An Updated Systematic Review and Meta-Analysis.

OBJECTIVES: Inotropic support is commonly used in patients with cardiogenic shock (CS). High-quality data guiding the use of dobutamine or milrinone among this patient population is limited. We compared the efficacy and safety of these two inotropes among patients with low cardiac output states (LCOS) or CS. DATA SOURCES: MEDLINE, Embase, and Cochrane Central Register of Controlled Trials were searched up to February 1, 2023, using key terms and index headings related to LCOS or CS and inotropes. DATA EXTRACTION: Two independent reviewers included studies that compared dobutamine to milrinone on all-cause in-hospital mortality, length of ICU stay, length of hospital stay, and significant arrhythmias in hospitalized patients. DATA SYNTHESIS: A total of eleven studies with 21,084 patients were included in the meta-analysis. Only two randomized controlled trials were identified. The primary outcome, all-cause mortality, favored milrinone in observational studies only (odds ratio [OR] 1.19 (95% CI, 1.02-1.39; p = 0.02). In-hospital length of stay (LOS) was reduced with dobutamine in observational studies only (mean difference -1.85 d; 95% CI -3.62 to -0.09; p = 0.04). There was no difference in the prevalence of significant arrhythmias or in ICU LOS. CONCLUSIONS: Only limited data exists supporting the use of one inotropic agent over another exists. Dobutamine may be associated with a shorter hospital LOS; however, there is also a potential for increased all-cause mortality. Larger randomized studies sufficiently powered to detect a difference in these outcomes are required to confirm these findings.

Inotrope versus placebo therapy in cardiogenic shock: Rationale and study design of the CAPITAL DOREMI2 trial.

BACKGROUND: Cardiogenic shock (CS) is a state of end-organ hypoperfusion related to cardiac dysfunction. Current guidelines recommend consideration of inotrope therapy in patients with CS, however no robust data support their use. The purpose of the CAPITAL DOREMI2 trial is to examine the efficacy and safety of inotrope therapy against placebo in the initial resuscitation of patients with CS. METHODS AND DESIGN: This is a multi-center, double-blind, randomized, placebo-controlled trial comparing single-agent inotrope therapy to placebo in patients with CS. A total of 346 participants with Society for Cardiovascular Angiography and Interventions class C or D CS will be randomized in a 1:1 fashion to inotrope or placebo therapy, which will be administered over a 12-hour period. After this period, participants will continue open-label therapies at the discretion of the treating team. The primary outcome is a composite of all-cause in-hospital death, and, as measured during the 12-hour intervention period, any of: sustained hypotension or high dose vasopressor requirements, lactate greater than 3.5 mmol/L at 6 hours or thereafter, need for mechanical circulatory support, arrhythmia leading to emergent electrical cardioversion, and resuscitated cardiac arrest. All participants will be followed for the duration of their hospitalization, and secondary outcomes will be assessed at the time of discharge. IMPLICATION: This trial will be the first to establish the safety and efficacy of inotrope therapy against placebo in a population of patients with CS and has the potential to alter the standard care provided to this group of patients.

Neuroprognostication in the Post Cardiac Arrest Patient: A Canadian Cardiovascular Society Position Statement.

Cardiac arrest (CA) is associated with a low rate of survival with favourable neurologic recovery. The most common mechanism of death after successful resuscitation from CA is withdrawal of life-sustaining measures on the basis of perceived poor neurologic prognosis due to underlying hypoxic-ischemic brain injury. Neuroprognostication is an important component of the care pathway for CA patients admitted to hospital but is complex, challenging, and often guided by limited evidence. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to evaluate the evidence underlying factors or diagnostic modalities available to determine prognosis, recommendations were generated in the following domains: (1) circumstances immediately after CA; (2) focused neurologic exam; (3) myoclonus and seizures; (4) serum biomarkers; (5) neuroimaging; (6) neurophysiologic testing; and (7) multimodal neuroprognostication. This position statement aims to serve as a practical guide to enhance in-hospital care of CA patients and emphasizes the adoption of a systematic, multimodal approach to neuroprognostication. It also highlights evidence gaps.

iBRIDGE: A Data Integration Method to Identify Inflamed Tumors from Single-cell RNA-Seq Data and Differentiate Cell Type-Specific Markers of Immune-Cell Infiltration.

The development of immune checkpoint-based immunotherapies has been a major advancement in the treatment of cancer, with a subset of patients exhibiting durable clinical responses. A predictive biomarker for immunotherapy response is the preexisting T-cell infiltration in the tumor immune microenvironment (TIME). Bulk transcriptomics-based approaches can quantify the degree of T-cell infiltration using deconvolution methods and identify additional markers of inflamed/cold cancers at the bulk level. However, bulk techniques are unable to identify biomarkers of individual cell types. Although single-cell RNA sequencing (scRNA-seq) assays are now being used to profile the TIME, to our knowledge there is no method of identifying patients with a T-cell inflamed TIME from scRNA-seq data. Here, we describe a method, iBRIDGE, which integrates reference bulk RNA-seq data with the malignant subset of scRNA-seq datasets to identify patients with a T-cell inflamed TIME. Using two datasets with matched bulk data, we show iBRIDGE results correlated highly with bulk assessments (0.85 and 0.9 correlation coefficients). Using iBRIDGE, we identified markers of inflamed phenotypes in malignant cells, myeloid cells, and fibroblasts, establishing type I and type II interferon pathways as dominant signals, especially in malignant and myeloid cells, and finding the TGFß-driven mesenchymal phenotype not only in fibroblasts but also in malignant cells. Besides relative classification, per-patient average iBRIDGE scores and independent RNAScope quantifications were used for threshold-based absolute classification. Moreover, iBRIDGE can be applied to in vitro grown cancer cell lines and can identify the cell lines that are adapted from inflamed/cold patient tumors.

Early Versus Delayed Coronary Angiography After Out-of-Hospital Cardiac Arrest Without ST-Segment Elevation-A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The optimal timing of coronary angiography remains unclear following out-of-hospital cardiac arrest (OHCA) without ST elevation on electrocardiogram. The objective of this systematic review and meta-analysis was to evaluate the efficacy and safety of early angiography versus delayed angiography following OHCA without ST elevation. DATA SOURCES: The databases MEDLINE, PubMed EMBASE, and CINHAL, as well as unpublished sources from inception to March 9, 2022. STUDY SELECTION: A systematic search was performed for randomized controlled trials of adult patients after OHCA without ST elevation who were randomized to early as compared to delayed angiography. DATA EXTRACTION: Reviewers screened and abstracted data independently and in duplicate. The certainty of evidence was assessed for each outcome using the Grading Recommendations Assessment, Development and Evaluation approach. The protocol was preregistered (CRD 42021292228). DATA SYNTHESIS: Six trials were included (n = 1,590 patients). Early angiography probably has no effect on mortality (relative risk [RR] 1.04; 95% CI 0.94-1.15; moderate certainty) and may have no effect on survival with good neurologic outcome (RR 0.97; 95% CI 0.87-1.07; low certainty) or ICU length of stay (LOS) (mean difference 0.41 days fewer; 95% CI -1.3 to 0.5 d; low certainty). Early angiography has an uncertain effect on adverse events. CONCLUSIONS: In OHCA patients without ST elevation, early angiography probably has no effect on mortality and may have no effect on survival with good neurologic outcome and ICU LOS. Early angiography has an uncertain effect on adverse events.

Epinephrine in Out-of-Hospital Cardiac Arrest: A Network Meta-analysis and Subgroup Analyses of Shockable and Nonshockable Rhythms.

BACKGROUND: Epinephrine is the most commonly used drug in out-of-hospital cardiac arrest (OHCA) resuscitation, but evidence supporting its efficacy is mixed. RESEARCH QUESTION: What are the comparative efficacy and safety of standard dose epinephrine, high-dose epinephrine, epinephrine plus vasopressin, and placebo or no treatment in improving outcomes after OHCA? STUDY DESIGN AND METHODS: In this systematic review and network meta-analysis of randomized controlled trials, we searched six databases from inception through June 2022 for randomized controlled trials evaluating epinephrine use during OHCA resuscitation. We performed frequentist random-effects network meta-analysis and present ORs and 95% CIs. We used the the Grading of Recommendations, Assessment, Development, and Evaluation approach to rate the certainty of evidence. Outcomes included return of spontaneous circulation (ROSC), survival to hospital admission, survival to discharge, and survival with good functional outcome. RESULTS: We included 18 trials (21,594 patients). Compared with placebo or no treatment, high-dose epinephrine (OR, 4.27; 95% CI, 3.68-4.97), standard-dose epinephrine (OR, 3.69; 95% CI, 3.32-4.10), and epinephrine plus vasopressin (OR, 3.54; 95% CI, 2.94-4.26) all increased ROSC. High-dose epinephrine (OR, 3.53; 95% CI, 2.97-4.20), standard-dose epinephrine (OR, 3.00; 95% CI, 2.66-3.38), and epinephrine plus vasopressin (OR, 2.79; 95% CI, 2.27-3.44) all increased survival to hospital admission as compared with placebo or no treatment. However, none of these agents may increase survival to discharge or survival with good functional outcome as compared with placebo or no treatment. Compared with placebo or no treatment, standard-dose epinephrine improved survival to discharge among patients with nonshockable rhythm (OR, 2.10; 95% CI, 1.21-3.63), but not in those with shockable rhythm (OR, 0.85; 95% CI, 0.39-1.85). INTERPRETATION: Use of standard-dose epinephrine, high-dose epinephrine, and epinephrine plus vasopressin increases ROSC and survival to hospital admission, but may not improve survival to discharge or functional outcome. Standard-dose epinephrine improved survival to discharge among patients with nonshockable rhythm, but not those with shockable rhythm. TRIAL REGISTRY: Center for Open Science: https://osf.io/arxwq.

Efficacy and safety of corticosteroids in cardiac arrest: a systematic review, meta-analysis and trial sequential analysis of randomized control trials.

BACKGROUND: Post-cardiac arrest, outcomes for most patients are poor, regardless of setting. Many patients who do achieve spontaneous return of circulation require vasopressor therapy to maintain organ perfusion. There is some evidence to support the use of corticosteroids in cardiac arrest. RESEARCH QUESTION: Assess the efficacy and safety of corticosteroids in patients following in- and out-of-hospital cardiac arrest. STUDY DESIGN AND METHODS: We searched databases CINAHL, EMBASE, LILACS, MEDLINE, Web of Science, CENTRAL, ClinicalTrails.gov, and ICTRP. We included randomized controlled trials (RCTs) that examined the efficacy and safety of corticosteroids, as compared to placebo or usual care in patients post-cardiac arrest. We pooled estimates of effect size using random effects meta-analysis and report relative risk (RR) with 95% confidence intervals (CIs). We assessed risk of bias (ROB) for the included trials using the modified Cochrane ROB tool and rated the certainty of evidence using Grading of Recommendations Assessment, Development and Evaluation methodology. RESULTS: We included 8 RCTs (n = 2213 patients). Corticosteroids administered post-cardiac arrest had an uncertain effect on mortality measured at the longest point of follow-up (RR 0.96, 95% CI 0.90-1.02, very low certainty, required information size not met using trial sequential analysis). Corticosteroids probably increase return of spontaneous circulation (ROSC) (RR 1.32, 95% CI 1.18-1.47, moderate certainty) and may increase the likelihood of survival with good functional outcome (RR 1.49, 95% CI 0.87-2.54, low certainty). Corticosteroids may decrease the risk of ventilator associated pneumonia (RR 0.76, 95% CI 0.46-1.09, low certainty), may increase renal failure (RR 1.29, 95% CI 0.84-1.99, low certainty), and have an uncertain effect on bleeding (RR 2.04, 95% CI 0.53-7.84, very low certainty) and peritonitis (RR 10.54, 95% CI 2.99-37.19, very low certainty). CONCLUSIONS: In patients during or after cardiac arrest, corticosteroids have an uncertain effect on mortality but probably increase ROSC and may increase the likelihood of survival with good functional outcome at hospital discharge. Corticosteroids may decrease ventilator associated pneumonia, may increase renal failure, and have an uncertain effect on bleeding and peritonitis. However, the pooled evidence examining these outcomes was sparse and imprecision contributed to low or very low certainty of evidence.

Arrhythmic Events and Mortality in Patients With Cardiogenic Shock on Inotropic Support: Results of the DOREMI Randomized Trial.

BACKGROUND: Inotropic support is widely used in the management of cardiogenic shock (CS). Existing data on the incidence and significance of arrhythmic events in patients with CS on inotropic support is at high risk of bias. METHODS: The Dobutamine Compared to Milrinone (DOREMI) trial randomized patients to receive dobutamine or milrinone in a double-blind fashion. Patients with and without arrhythmic events (defined as arrhythmias requiring intervention or sustained ventricular arrhythmias) were compared to identify factors associated with their occurrence, and to examine their association with in-hospital mortality and secondary outcomes. RESULTS: Ninety-two patients (47.9%) had arrhythmic events, occurring equally with dobutamine and milrinone (P = 0.563). The need for vasopressor support at initiation of the inotrope and a history of atrial fibrillation were positively associated with arrhythmic events, whereas predominant right ventricular dysfunction, previous myocardial infarction, and increasing left ventricular ejection fraction were negatively associated with them. Supraventricular arrhythmic events were not associated with mortality (relative risk [RR], 0.97; 95% confidence interval [CI], 0.68-1.40; P = 0.879) but were positively associated with resuscitated cardiac arrests and hospital length of stay. Ventricular arrhythmic events were positively associated with mortality (RR, 1.66; 95% CI, 1.13-2.43; P = 0.026) and resuscitated cardiac arrests. Arrhythmic events were most often treated with amiodarone (97%) and electrical cardioversion (27%), which were not associated with mortality. CONCLUSIONS: Clinically relevant arrhythmic events occur in approximately one-half of patients with CS treated with dobutamine or milrinone and are associated with adverse clinical outcomes. Five factors may help to identify patients most at risk of arrhythmic events.