Contemporary Training in American Critical Care Cardiology: Minnesota Critical Care Cardiology Education Summit: JACC Scientific Expert Panel.

This consensus statement emerges from collaborative efforts among leading figures in critical care cardiology throughout the United States, who met to share their collective expertise on issues faced by those active in or pursuing contemporary critical care cardiology education. The panel applied fundamentals of adult education and curriculum design, reviewed requisite training necessary to provide high-quality care to critically ill patients with cardiac pathology, and devoted attention to a purposeful approach emphasizing diversity, equity, and inclusion in developing this nascent field. The resulting paper offers a comprehensive guide for current trainees, with insights about the present landscape of critical care cardiology while highlighting issues that need to be addressed for continued advancement. By delineating future directions with careful consideration and intentionality, this Expert Panel aims to facilitate the continued growth and maturation of critical care cardiology education and practice.

Eosinophilic Endomyocarditis After COVID-19 Infection in a Heart Transplant Recipient.

Eosinophilic myocarditis (EM) is a rare cause of heart failure, with high in-hospital mortality associated with fulminant disease. A 61-year-old female transplant recipient was diagnosed with COVID-19 after presenting with 2 days of constitutional symptoms. She developed acute heart failure from EM. After an initial response to inotropic support and corticosteroids, she had a relapse with de novo peripheral eosinophilia which responded to further eosinophilic myocarditis management and the addition of mepolizumab. Although there have been reports after COVID-19 vaccination, association with active SARS-CoV-2 infection is rare. This paper reports, for the first time, the case of a heart transplant recipient with EM after COVID-19.

Mortality Risk Stratification Utilizing Artificial Intelligence Electrocardiogram for Hyperkalemia in Cardiac Intensive Care Unit Patients.

Background: Hyperkalemia has been associated with increased mortality in cardiac intensive care unit (CICU) patients. An artificial intelligence (AI) enhanced electrocardiogram (ECG) can predict hyperkalemia, and other AI-ECG algorithms have demonstrated mortality risk-stratification in CICU patients. Objectives: The authors hypothesized that the AI-ECG hyperkalemia algorithm could stratify mortality risk beyond laboratory serum potassium measurement alone. Methods: We included 11,234 unique Mayo Clinic CICU patients admitted from 2007 to 2018 with a 12-lead ECG and blood potassium (K) level obtained at admission with K ≥5 mEq/L defining hyperkalemia. ECGs underwent AI evaluation for the probability of hyperkalemia (probability >0.5 defined as positive). Hospital mortality was analyzed using logistic regression, and survival to 1 year was estimated using Kaplan-Meier and Cox analysis. Results: In the final cohort (n = 11,234), the mean age was 69.6 ± 10.5 years, 37.8% were females, and 92.4% were White. Chronic kidney disease was present in 20.2%. The mean laboratory potassium value for the cohort was 4.2 ± 0.3 mEq/L. The AI-ECG predicted hyperkalemia in 33.9% (n = 3,810) of CICU patients and 12.9% (n = 1,451) of patients had laboratory-confirmed hyperkalemia (K ≥5 mEq/L). In-hospital mortality increased in false-positive, false-negative, and true-positive patients, respectively (P < 0.001), and each of these patient groups had successively lower survival out to 1 year. Conclusions: AI-ECG-based prediction of hyperkalemia, even with a normal laboratory potassium value, was associated with higher in-hospital mortality and lower 1-year survival in CICU patients. This study demonstrated that AI-ECG probability of hyperkalemia may enable rapid individualized risk stratification in critically ill patients beyond laboratory value alone.

Sex-Based Survival Outcomes in Cardiogenic Shock.

BACKGROUND: Sex-based disparities have been demonstrated in care delivery for females with cardiogenic shock (CS), including lower use of coronary angiography (CAG), percutaneous intervention (PCI) and mechanical circulatory support (MCS). We evaluated whether sex-based disparities exist and are associated with worse CS outcomes in females. METHODS: We studied a retrospective cohort of 1498 consecutive, unique adult cardiovascular intensive care unit (CICU) admissions with CS from 2007-2018. RESULTS: Compared to males, females (n = 566, 37.1%) were older (71.7 vs 67.8 years; P < 0.001) but had similar burdens of medical comorbidities. Acute myocardial infarction (AMI) was present in 54.1% of females and 59.1% of males (P = 0.06). There were no sex-based differences in the use of CAG and PCI, but females received temporary MCS less commonly. Specifically, females with non-AMI CS received MCS devices less commonly (17.6% vs 24.4%; P = 0.04). There was no difference in in-hospital or 1-year mortality rates between the sexes. Compared to males, females who received PCI had lower risks of 1-year mortality (unadjusted HR 0.72; P = 0.03), whereas females who received CAG without PCI had higher risks of 1-year mortality (unadjusted HR 1.41; P = 0.02). CONCLUSIONS: No sex-based disparities in mortality due to CS were demonstrated in this large, diverse cohort of patients with CICU admissions. Females who underwent PCI demonstrated lower risks of 1-year mortality, whereas females who underwent CAG without PCI demonstrated higher risks of 1-year mortality compared to males. This may reflect underuse of PCI as a mortality-reducing therapy in females.

Multidisciplinary Care Teams in Acute Cardiovascular Care: A Review of Composition, Logistics, Outcomes, Training, and Future Directions.

As cardiovascular care continues to advance and with an aging population with higher comorbidities, the epidemiology of the cardiac intensive care unit has undergone a paradigm shift. There has been increasing emphasis on the development of multidisciplinary teams (MDTs) for providing holistic care to complex critically ill patients, analogous to heart teams for chronic cardiovascular care. Outside of cardiovascular medicine, MDTs in critical care medicine focus on implementation of guideline-directed care, prevention of iatrogenic harm, communication with patients and families, point-of-care decision-making, and the development of care plans. MDTs in acute cardiovascular care include physicians from cardiovascular medicine, critical care medicine, interventional cardiology, cardiac surgery, and advanced heart failure, in addition to nonphysician team members. In this document, we seek to describe the changes in patients in the cardiac intensive care unit, health care delivery, composition, logistics, outcomes, training, and future directions for MDTs involved in acute cardiovascular care. As a part of the comprehensive review, we performed a scoping of concepts of MDTs, acute hospital care, and cardiovascular conditions and procedures.

Utilization of inpatient palliative care services in cardiac arrest complicating acute pulmonary embolism.

Introduction: The role of palliative care services in patients with cardiac arrest complicating acute pulmonary embolism has been infrequently studied. Methods: All adult admissions with pulmonary embolism complicating cardiac arrest were identified using the National Inpatient Sample (2016-2020). The primary outcome of interest was the utilization of palliative care services. Secondary outcomes included predictors of palliative care utilization and its association of with in-hospital mortality, do-not-resuscitate status, discharge disposition, length of stay, and total hospital charges. Multivariable regression analysis was used to adjust for confounding. Results: Between 01/01/2016 and 12/31/2020, of the 7,320 admissions with pulmonary embolism complicating cardiac arrest, 1229 (16.8 %) received palliative care services. Admissions receiving palliative care were on average older (68.1 ± 0.9 vs. 63.2 ± 0.4 years) and with higher baseline comorbidity (Elixhauser index 6.3 ± 0.1 vs 5.6 ± 0.6) (all p < 0.001). Additionally, this cohort had higher rates of non-cardiac organ failure (respiratory, renal, hepatic, and neurological) and invasive mechanical ventilation (all p < 0.05). Catheter-directed therapy was used less frequently in the cohort receiving palliative care, (2.8 % vs 7.9 %; p < 0.001) whereas the rates of systemic thrombolysis, mechanical and surgical thrombectomy were comparable. The cohort receiving palliative care services had higher in-hospital mortality (85.7 % vs. 69.1 %; adjusted odds ratio 2.20 [95 % CI 1.41-3.42]; p < 0.001). This cohort also had higher rates of do-not-resuscitate status and fewer discharges to home, but comparable hospitalization costs and length of hospital stay. Conclusions: Palliative care services are used in only 16.8 % of admissions with cardiac arrest complicating pulmonary embolism with significant differences in the populations, suggestive of selective consultation.

Unsupervised machine learning to identify subphenotypes among cardiac intensive care unit patients with heart failure.

AIMS: Hospitalized patients with heart failure (HF) are a heterogeneous population, with multiple phenotypes proposed. Prior studies have not examined the biological phenotypes of critically ill patients with HF admitted to the contemporary cardiac intensive care unit (CICU). We aimed to leverage unsupervised machine learning to identify previously unknown HF phenotypes in a large and diverse cohort of patients with HF admitted to the CICU. METHODS: We screened 6008 Mayo Clinic CICU patients with an admission diagnosis of HF from 2007 to 2018 and included those without missing values for common laboratory tests. Consensus k-means clustering was performed based on 10 common admission laboratory values (potassium, chloride, anion gap, blood urea nitrogen, haemoglobin, red blood cell distribution width, mean corpuscular volume, platelet count, white blood cell count and neutrophil-to-lymphocyte ratio). In-hospital mortality was evaluated using logistic regression, and 1 year mortality was evaluated using Cox proportional hazard models after multivariable adjustment. RESULTS: Among 4877 CICU patients with HF who had complete admission laboratory data (mean age 69.4 years, 38.4% females), we identified five clusters with divergent demographics, comorbidities, laboratory values, admission diagnoses and use of critical care therapies. We labelled these clusters based on the characteristic laboratory profile of each group: uncomplicated (25.7%), iron-deficient (14.5%), cardiorenal (18.4%), inflamed (22.3%) and hypoperfused (19.2%). In-hospital mortality occurred in 10.7% and differed between the phenotypes: uncomplicated, 2.7% (reference); iron-deficient, 8.1% [adjusted odds ratio (OR) 2.18 (1.38-3.48), P < 0.001]; cardiorenal, 10.3% [adjusted OR 2.11 (1.37-3.32), P < 0.001]; inflamed, 12.5% [adjusted OR 1.79 (1.18-2.76), P = 0.007]; and hypoperfused, 21.9% [adjusted OR 4.32 (2.89-6.62), P < 0.001]. These differences in mortality between phenotypes were consistent when patients were stratified based on demographics, aetiology, admission diagnoses, mortality risk scores, shock severity and systolic function. One-year mortality occurred in 31.5% and differed between the phenotypes: uncomplicated, 11.9% (reference); inflamed, 26.8% [adjusted hazard ratio (HR) 1.56 (1.27-1.92), P < 0.001]; iron-deficient, 33.8% [adjusted HR 2.47 (2.00-3.04), P < 0.001]; cardiorenal, 41.2% [adjusted HR 2.41 (1.97-2.95), P < 0.001]; and hypoperfused, 52.3% [adjusted HR 3.43 (2.82-4.18), P < 0.001]. Similar findings were observed for post-discharge 1 year mortality. CONCLUSIONS: Unsupervised machine learning clustering can identify multiple distinct clinical HF phenotypes within the CICU population that display differing mortality profiles both in-hospital and at 1 year. Mortality was lowest for the uncomplicated HF phenotype and highest for the hypoperfused phenotype. The inflamed phenotype had comparatively higher in-hospital mortality yet lower post-discharge mortality, suggesting divergent short-term and long-term prognosis.

Validation of Noninvasive Detection of Hyperkalemia by Artificial Intelligence-Enhanced Electrocardiography in High Acuity Settings.

Background: Artificial intelligence (AI) electrocardiogram (ECG) analysis can enable detection of hyperkalemia. In this validation, we assessed the algorithm's performance in two high acuity settings. Methods: An emergency department (ED) cohort (February to August 2021) and a mixed intensive care unit (ICU) cohort (August 2017 to February 2018) were identified and analyzed separately. For each group, pairs of laboratory-collected potassium and 12 lead ECGs obtained within 4 hours of each other were identified. The previously developed AI ECG algorithm was subsequently applied to leads 1 and 2 of the 12 lead ECGs to screen for hyperkalemia (potassium >6.0 mEq/L). Results: The ED cohort (N=40,128) had a mean age of 60 years, 48% were male, and 1% (N=351) had hyperkalemia. The area under the curve (AUC) of the AI-enhanced ECG (AI-ECG) to detect hyperkalemia was 0.88, with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and positive likelihood ratio (LR+) of 80%, 80%, 3%, 99.8%, and 4.0, respectively, in the ED cohort. Low-eGFR (<30 ml/min) subanalysis yielded AUC, sensitivity, specificity, PPV, NPV, and LR+ of 0.83, 86%, 60%, 15%, 98%, and 2.2, respectively, in the ED cohort. The ICU cohort (N=2636) had a mean age of 65 years, 60% were male, and 3% (N=87) had hyperkalemia. The AUC for the AI-ECG was 0.88 and yielded sensitivity, specificity, PPV, NPV, and LR+ of 82%, 82%, 14%, 99%, and 4.6, respectively in the ICU cohort. Low-eGFR subanalysis yielded AUC, sensitivity, specificity, PPV, NPV, and LR+ of 0.85, 88%, 67%, 29%, 97%, and 2.7, respectively in the ICU cohort. Conclusions: The AI-ECG algorithm demonstrated a high NPV, suggesting that it is useful for ruling out hyperkalemia, but a low PPV, suggesting that it is insufficient for treating hyperkalemia.

Premature Acute Myocardial Infarction Treated With Invasive Revascularization: Comparing STEMI With NSTEMI in a Population-Based Study of Young Patients.

BACKGROUND: Acute myocardial infarction (AMI) usually presents in older populations, in which there are established demographic and outcome differences for ST-elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI). No similar comparisons for AMI in the young population exist. METHODS: We compared all index NSTEMI and STEMI hospitalizations in young (18-45 years) patients who required revascularization in Alberta, Canada. Outcomes were survival to discharge, and a composite of heart failure hospitalization, cardiac arrest hospitalization, and all-cause mortality at 1 and 5 years. RESULTS: There were 1679 patients included with an index AMI who required revascularization: 655 (39.0%) NSTEMI and 1024 (61.0%) STEMI. The population was disproportionately male (86%), particularly in STEMI patients (87.3%). Marked dyslipidemia (35%) and active smoking (42%) were common, with similar rates among groups. Percutaneous coronary intervention was used in 98.7% of STEMI and 91.5% of NSTEMI patients (P < 0.001), with the remainder who underwent surgical revascularization. The in-hospital mortality rate during index AMI was higher in STEMI compared with NSTEMI patients (1.7% vs 0%; P < 0.001). The rates of the composite outcome were similar for both groups at 1 and 5 years of follow-up in patients who survived to index hospital discharge. After adjusting for sex, age, heart failure and/or cardiac arrest at index AMI, outcomes remained similar among groups at 1 and 5 years. CONCLUSIONS: In young patients with AMI, STEMI was a disproportionately male phenomenon and associated with higher mortality at index hospitalization. One-year and 5-year outcomes were similar among STEMI and NSTEMI patients in those discharged alive at index AMI. Smoking and dyslipidemia appear to be major risk factors in the young.

Arterial hyperoxia and mortality in the cardiac intensive care unit.

BACKGROUND: Arterial hyperoxia (hyperoxemia), defined as a high arterial partial pressure of oxygen (PaO2), has been associated with adverse outcomes in critically ill populations, but has not been examined in the cardiac intensive care unit (CICU). We evaluated the association between exposure to hyperoxia on admission with in-hospital mortality in a mixed CICU cohort. METHODS: We included unique Mayo Clinic CICU patients admitted from 2007 to 2018 with admission PaO2 data (defined as the PaO2 value closest to CICU admission) and no hypoxia (PaO2 < 60mmHg). The admission PaO2 was evaluated as a continuous variable and categorized (60-100 mmHg, 101-150 mmHg, 151-200 mmHg, 201-300 mmHg, >300 mmHg). Logistic regression was used to evaluate predictors of in-hospital mortality before and after multivariable adjustment. RESULTS: We included 3,368 patients with a median age of 70.3 years; 70.3% received positive-pressure ventilation. The median PaO2 was 99 mmHg, with a distribution as follows: 60-100 mmHg, 51.9%; 101-150 mmHg, 28.6%; 151-200 mmHg, 10.6%; 201-300 mmHg, 6.4%; >300 mmHg, 2.5%. A J-shaped association between admission PaO2 and in-hospital mortality was observed, with a nadir around 100 mmHg. A higher PaO2 was associated with increased in-hospital mortality (adjusted OR 1.17 per 100 mmHg higher, 95% CI 1.01-1.34, p = 0.03). Patients with PaO2 >300 mmHg had higher in-hospital mortality versus PaO2 60-100 mmHg (adjusted OR 2.37, 95% CI 1.41-3.94, p < 0.001). CONCLUSIONS: Hyperoxia at the time of CICU admission is associated with higher in-hospital mortality, primarily in those with severely elevated PaO2 >300 mmHg.

Admission Total Leukocyte Count as a Predictor of Mortality in Cardiac Intensive Care Unit Patients.

Background: Inflammation is a sequela of cardiovascular critical illness and a risk factor for mortality. Objectives: This study aimed to evaluate the association between white blood cell count (WBC) and mortality in a broad population of patients admitted to the cardiac intensive care unit (CICU). Methods: This retrospective cohort study included patients admitted to the Mayo Clinic CICU between 2007 and 2018. We analyzed WBC as a continuous variable and then categorized WBC as low (<4.0 × 103/mL), normal (≥4.0 to <11.0 × 103/mL), high (≥11.0 to <22.0 × 103/mL), or very high (≥22.0 × 103/mL). The association between WBC and in-hospital mortality was evaluated using multivariable logistic regression and random forest models. Results: We included 11,699 patients with a median age of 69.3 years (37.6% females). Median WBC was 9.6 (IQR: 7.4-12.7). Mortality was higher in the low (10.5%), high (12.0%), and very high (33.3%) WBC groups relative to the normal WBC group (5.3%). A rising WBC was incrementally associated with higher in-hospital mortality after adjustment (AICc adjusted OR: 1.03 [95% CI: 1.02-1.04] per 1 × 103 increase in WBC). After adjustment, only the high (AICc adjusted OR: 1.37 [95% CI: 1.15-1.64]) and very high (AICc adjusted OR: 1.99 [1.47-2.71]) WBC groups remained associated with increased risk of in-hospital mortality. Conclusions: Leukocytosis is associated with an increased mortality risk in a diverse cohort of CICU patients. This readily available marker of systemic inflammation may be useful for risk stratification within the increasingly complex CICU patient population.

Cardiac Function Before Sepsis and Clinical Outcomes.

This cohort study characterizes heterogeneity in cardiac function prior to sepsis and describes associations with hospitalization outcomes and mortality.

Early Serial Assessment of Aggregate Vasoactive Support and Mortality in Cardiogenic Shock: Insights From the Critical Care Cardiology Trials Network Registry.

BACKGROUND: Associations of early changes in vasoactive support with cardiogenic shock (CS) mortality remain incompletely defined. METHODS: The Critical Care Cardiology Trials Network is a multicenter registry of cardiac intensive care units. Patients admitted with CS (2018-2023) had vasoactive dosing assessed at 4 and 24 hours from cardiac intensive care unit admission and quantified by the vasoactive-inotropic score (VIS). Prognostic associations of VIS at both time points, as well as change in VIS from 4 to 24 hours, were examined. Interaction testing was performed based on mechanical circulatory support status. RESULTS: Among 3665 patients, 82% had a change in VIS <10, with 7% and 11% having a ≥10-point increase and decrease from 4 to 24 hours, respectively. The 4 and 24-hour VIS were each associated with cardiac intensive care unit mortality (13%-45% and 11%-73% for VIS <10 to ≥40, respectively; Ptrend <0.0001 for each). Stratifying by the 4-hour VIS, changes in VIS from 4 to 24 hours had a graded association with mortality, ranging from a 2- to >4-fold difference in mortality comparing those with a ≥10-point increase to ≥10-point decrease in VIS (Ptrend <0.0001). The change in VIS alone provided good discrimination of cardiac intensive care unit mortality (C-statistic, 0.72 [95% CI, 0.70-0.75]) and improved discrimination of the 24-hour Sequential Organ Failure Assessment score (0.72 [95% CI, 0.69-0.74] to 0.76 [95% CI, 0.74-0.78]) and the clinician-assessed Society for Cardiovascular Angiography and Interventions shock stage (0.72 [95% CI, 0.70-0.74] to 0.77 [95% CI, 0.75-0.79]). Although present in both groups, the mortality risk associated with VIS was attenuated in patients managed with versus without mechanical circulatory support (odds ratio per 10-point higher 24-hour VIS, 1.36 [95% CI, 1.23-1.49] versus 1.84 [95% CI, 1.69-2.01]; Pinteraction <0.0001). CONCLUSIONS: Early changes in the magnitude of vasoactive support in CS are associated with a gradient of risk for mortality. These data suggest that early VIS trajectory may improve CS prognostication, with the potential to be leveraged for clinical decision-making and research applications in CS.

Association between the shock index on admission and in-hospital mortality in the cardiac intensive care unit.

BACKGROUND: An elevated shock index (SI) predicts worse outcomes in multiple clinical arenas. We aimed to determine whether the SI can aid in mortality risk stratification in unselected cardiac intensive care unit patients. METHODS: We included admissions to the Mayo Clinic from 2007 to 2015 and stratified them based on admission SI. The primary outcome was in-hospital mortality, and predictors of in-hospital mortality were analyzed using multivariable logistic regression. RESULTS: We included 9,939 unique cardiac intensive care unit patients with available data for SI. Patients were grouped by SI as follows: < 0.6, 3,973 (40%); 0.6-0.99, 4,810 (48%); and ≥ 1.0, 1,156 (12%). After multivariable adjustment, both heart rate (adjusted OR 1.06 per 10 beats per minute higher; CI 1.02-1.10; p-value 0.005) and systolic blood pressure (adjusted OR 0.94 per 10 mmHg higher; CI 0.90-0.97; p-value < 0.001) remained associated with higher in-hospital mortality. As SI increased there was an incremental increase in in-hospital mortality (adjusted OR 1.07 per 0.1 beats per minute/mmHg higher, CI 1.04-1.10, p-Value < 0.001). A higher SI was associated with increased mortality across all examined admission diagnoses. CONCLUSION: The SI is a simple and universally available bedside marker that can be used at the time of admission to predict in-hospital mortality in cardiac intensive care unit patients.

Initial Triage and Management of Patients with Acute Aortic Syndromes.

The acute aortic syndromes (AAS) are life-threatening vascular compromises within the aortic wall. These include aortic dissection (AD), intramural hematoma (IMH), penetrating aortic ulcer (PAU), and blunt traumatic thoracic aortic injury (BTTAI). While patients classically present with chest pain, the presentation may be highly variable. Timely diagnosis is critical to initiate definitive treatment and maximize chances of survival. In high-risk patients, treatment should begin immediately, even while diagnostic evaluation proceeds. The mainstay of medical therapy is acute reduction of heart rate and blood pressure. Surgical intervention is often required but is informed by patient anatomy and extent of vascular compromise.

Need for a Cardiogenic Shock Team Collaborative-Promoting a Team-Based Model of Care to Improve Outcomes and Identify Best Practices.

Cardiogenic shock continues to carry a high mortality rate despite contemporary care, with no breakthrough therapies shown to improve survival over the past few decades. It is a time-sensitive condition that commonly results in cardiovascular complications and multisystem organ failure, necessitating multidisciplinary expertise. Managing patients with cardiogenic shock remains challenging even in well-resourced settings, and an important subgroup of patients may require cardiac replacement therapy. As a result, the idea of leveraging the collective cognitive and procedural proficiencies of multiple providers in a collaborative, team-based approach to care (the "shock team") has been advocated by professional societies and implemented at select high-volume clinical centers. A slowly maturing evidence base has suggested that cardiogenic shock teams may improve patient outcomes. Although several registries exist that are beginning to inform care, particularly around therapeutic strategies of pharmacologic and mechanical circulatory support, none of these are currently focused on the shock team approach, multispecialty partnership, education, or process improvement. We propose the creation of a Cardiogenic Shock Team Collaborative-akin to the successful Pulmonary Embolism Response Team Consortium-with a goal to promote sharing of care protocols, education of stakeholders, and discovery of how process and performance may influence patient outcomes, quality, resource consumption, and costs of care.

Variation in risk-adjusted cardiac intensive care unit (CICU) length of stay and the association with in-hospital mortality: An analysis from the Critical Care Cardiology Trials Network (CCCTN) registry.

BACKGROUND: Previous studies have suggested that there is wide variability in cardiac intensive care unit (CICU) length of stay (LOS); however, these studies are limited by the absence of detailed risk assessment at the time of admission. Thus, we evaluated inter-hospital differences in CICU LOS, and the association between LOS and in-hospital mortality. METHODS: Using data from the Critical Care Cardiology Trials Network (CCCTN) registry, we included 22,862 admissions between 2017 and 2022 from 35 primarily tertiary and quaternary CICUs that captured consecutive admissions in annual 2-month snapshots. The primary analysis compared inter-hospital differences in CICU LOS, as well as the association between CICU LOS and all-cause in-hospital mortality using a Fine and Gray competing risk model. RESULTS: The overall median CICU LOS was 2.2 (1.1-4.8) days, and the median hospital LOS was 5.9 (2.8-12.3) days. Admissions in the longest tertile of LOS tended to be younger with higher rates of pre-existing comorbidities, and had higher Sequential Organ Failure Assessment (SOFA) scores, as well as higher rates of mechanical ventilation, intravenous vasopressor use, mechanical circulatory support, and renal replacement therapy. Unadjusted all-cause in-hospital mortality was 9.3%, 6.7%, and 13.4% in the lowest, intermediate, and highest CICU LOS tertiles. In a competing risk analysis, individual patient CICU LOS was correlated (r2 = 0.31) with a higher risk of 30-day in-hospital mortality. The relationship remained significant in admissions with heart failure, ST-elevation myocardial infarction and non-ST segment elevation myocardial infarction. CONCLUSIONS: In a large registry of academic CICUs, we observed significant variation in CICU LOS and report that LOS is independently associated with all-cause in-hospital mortality. These findings could potentially be used to improve CICU resource utilization planning and refine risk prognostication in critically ill cardiovascular patients.