•With contemporary STEMI care, the need for prolonged telemetry for surveillance of an actionable arrhythmia is unclear.•Beyond the first 24-48 hours, the incident rate for an actionable arrhythmia is low.•Traditionally established prognostic variables in STEMI would likely guide triage for longer telemetry durations in STEMI.

BACKGROUND:To date, there has been no independent core lab angiographic analysis of patients with COVID-19 and STEMI. The study characterized the angiographic parameters of patients with COVID-19 and STEMI. METHODS:Angiograms of patients with COVID-19 and STEMI from the North American COVID-19 Myocardial Infarction (NACMI) Registry were sent to a Core Laboratory in Vancouver, Canada. Culprit lesion(s), Thrombolysis In Myocardial Infarction (TIMI) flow, Thrombus Grade Burden (TGB), and percutaneous coronary intervention (PCI) outcome were assessed. RESULTS:From 234 patients, 74% had one culprit lesion, 14% had multiple culprits and 12% had no culprit identified. Multivessel thrombotic disease and multivessel CAD were found in 27% and 53% of patients, respectively. Stent thrombosis accounted for 12% of the presentations and occurred in 55% of patients with previous coronary stents. Of the 182 who underwent PCI, 60 (33%) had unsuccessful PCI due to post-PCI TIMI flow <3 (43/60), residual high thrombus burden (41/60) and/or thrombus related complications (27/60). In-hospital mortality for successful, partially successful, and unsuccessful PCI was 14%, 13%, and 27%, respectively. Unsuccessful PCI was associated with increased risk of in-hospital mortality (risk ratio [RR] 1.96; 95% CI: 1.05-3.66, P = .03); in the adjusted model this estimate was attenuated (RR: 1.24; 95% CI: 0.65-2.34, P = .51). CONCLUSION:In patients with COVID-19 and STEMI, thrombus burden was pervasive with notable rates of multivessel thrombotic disease and stent thrombosis. Post-PCI, persistent thrombus and sub-optimal TIMI 3 flow rates led to one-third of the PCI's being unsuccessful, which decreased over time but remained an important predictor of in-hospital mortality.

Introduction: While timely therapy of neurologic and cardiac emergencies can improve outcomes, patients often fail to identify acute events resulting in delays in seeking emergency care. ECHAS is a smartphone application and sensor system aimed to reduce patient-related delay. We performed a retrospective study to test ECHAS in identifying patients who required emergency assessment for possible myocardial infarction (MI) or stroke. Methods: We enrolled 202 patients (57 with stroke-like, 145 MI-like symptoms) who presented to the ED at a single center in Canada. Participants answered yes-no questions about their prior history, acute symptoms, and performed a finger-tapping test on an Apple iPhone with ECHAS. Answers resulted in a risk score that guided one of the three triage decisions: 1) call 911, 2) call hotline, or 3) call your primary care physician. The ground truth for the triage decision assessment was the appropriateness of the patient’s visit to the ED. Specificity could not be calculated due to low numbers of patients who did not need emergency evaluation. Results: The mean time to complete the acute assessment was 60 seconds for MI and 111 seconds for stroke. ECHAS output recommended 66% of patients call 911, 30% hotline, and 4% primary care follow-up. The sensitivity to identify the need for emergency evaluation was 0.98. The sensitivity to identify patients who were admitted for possible MI or stroke was 1.0. A negative correlation was found between low ECHAS score and prolonged symptom onset to hospital arrival time for MI-like symptoms (r = -0.21, p < 0.05). Patients found ECHAS to be very useable (Fig 1). Conclusion: The ECHAS application was highly sensitive and easily usable in guiding patients to identify medical emergencies without input by healthcare personnel. These pilot results will drive a planned 4,000-patient prospective randomized trial to evaluate whether ECHAS will reduce times from symptom onset to first medical contact for MI and stroke.

Processing liquid chromatography-mass spectrometry-based metabolomics data using computational programs often introduces additional quantitative uncertainty, termed computational variation in a previous work. This work develops a computational solution to automatically recognize metabolic features with computational variation in a metabolomics data set. This tool, AVIR (short for "Accurate eValuation of alIgnment and integRation"), is a support vector machine-based machine learning strategy (https://github.com/HuanLab/AVIR). The rationale is that metabolic features with computational variation have a poor correlation between chromatographic peak area and peak height-based quantifications across the samples in a study. AVIR was trained on a set of 696 manually curated metabolic features and achieved an accuracy of 94% in a 10-fold cross-validation. When tested on various external data sets from public metabolomics repositories, AVIR demonstrated an accuracy range of 84%-97%. Finally, tested on a large-scale metabolomics study, AVIR clearly indicated features with computational variation and thus guided us to manually correct them. Our results show that 75.3% of the samples with computational variation had a relative intensity difference of over 20% after correction. This demonstrates the critical role of AVIR in reducing computational variation to improve quantitative certainty in untargeted metabolomics analysis.

BackgroundIn patients presenting with an acute coronary syndrome (ACS), the impact of efforts leveraged at bridging historical care gaps between Indigenous and non-Indigenous patients remains limited.MethodsFor consecutive ACS presentations (STEMI and NSTEMI/UA, respectively) at the Royal University Hospital, Saskatoon, we compared between self-identified Indigenous and non-Indigenous patients their demographics, treatments and all-cause mortality (in-hospital and 3-years). We used propensity score-inverse probability weighting to mitigate confounding, and Cox regression models to estimate the adjusted hazard (aHR, 95% confidence intervals) for all-cause mortality.ResultsOf 3946 ACS patients, 37.2% (n=1468) were STEMI of whom 11.3% (n=166) were Indigenous. Of the NSTEMI/UA (n=2478), 12.6% (n=311) were Indigenous. Overall, Indigenous compared with non-Indigenous patients were likely to be younger, female, have higher risk burden, and lived more remotely; Indigenous STEMI patients triaged to primary PCI had longer first medical contact-to-device times, while Indigenous NSTEMI/UA patients more likely to present with heart failure, cardiac arrest and/or cardiogenic shock.No significant differences were noted for in-hospital mortality (STEMI 8.4% vs 5.7%, p= 0.16; NSTEMI/UA 1.9% vs 1.6%, p=0.68), however, in follow-up, Indigenous STEMI patients associated with a higher all-cause mortality risk (aHR 1.98, 95% CI 1.19, 3.31, p=0.009) with no between-group differences evident for NSTEMI/UA (aHR 1.03, 95% CI 0.63 1.69, p=0.91).ConclusionsIndigenous compared with non-Indigenous patients presenting with an ACS had higher cardiovascular risk profiles, and consequently residual mortality risk. Improving primary care and intensifying secondary risk reduction, and particularly so for Indigenous patients, will substantially modify ACS outcomes in Saskatchewan.

The Coronavirus disease 2019 (COVID-19) pandemic has led to a significant increase in worldwide morbidity and mortality. Patients with COVID-19 are at risk for developing a variety of cardiovascular conditions including acute coronary syndromes, stress-induced cardiomyopathy, and myocarditis. Patients with COVID-19 who develop ST-elevation myocardial infarction (STEMI) are at a higher risk of morbidity and mortality when compared with their age- and sex-matched STEMI patients without COVID-19. We review current knowledge on the pathophysiology of STEMI in patients with COVID-19, clinical presentation, outcomes, and the effect of the COVID-19 pandemic on overall STEMI care.

Background: Deciphering which patients with low-gradient aortic valve disease have severe stenosis can be difficult. We aimed to correlate the postextrasystolic potentiation (PESP) with dobutamine stress echocardiography and multidetector computed tomography in patients with low-gradient aortic valve stenosis. Methods: Patients with an aortic valve area ≤1 cm 2 and a mean gradient <40 mm Hg were included. Aortic valve stenosis severity was assessed by a core lab with dobutamine stress echocardiography, followed by a multidetector computed tomography aortic valve score if indeterminate. A premature ventricular contraction was induced by intentional catheter contact with the myocardium within the left ventricle. PESP was calculated as a percent change of pre-to-post mean gradient. Multidetector computed tomography was used to measure the aortic valve calcification score, and subsequently, aortic valve calcification density. Results: Twenty-eight patients (age, 77±10 years; 19 female) were included. Dobutamine stress echocardiography increased mean gradient from baseline of 25±7 mm Hg to 36±11 mm Hg; pre-premature ventricular contraction mean gradient was 25±7 mm Hg and increased to post-premature ventricular contraction mean gradient of 32±10 mm Hg, representing a PESP of 24±11%. A ≥20% in PESP resulted in 100% sensitivity, 77% specificity, 83% positive predictive value, and 100% negative predictive value for diagnosing severe aortic valve stenosis. There was a significant correlation between PESP and projected aortic valve area and aortic valve calcification density (R=−0.64, P =0.0003; R=0.057, P =0.014, respectively). Conclusions: In patients with low-gradient aortic valve stenosis, catheter-induced premature ventricular contractions during cardiac catheterization causing ≥20% PESP has a 100% sensitivity for severe aortic valve stenosis. Validation of this 20% cutoff in larger groups with correlation to clinical end points is required.

Aims: The HLA system has been implicated as an underlying determinant for modulating the immune response to SARS-CoV-2. In this study, we aimed to determine the association of patients' HLA genetic profiles with the disease severity of COVID-19 infection.Methods: Prospective study was conducted on COVID-19 patients (n = 40) admitted to hospitals in Saskatoon, Canada, between March and December 2020. Next-generation sequencing was performed on the patient sam-ples to obtain high-resolution HLA typing profiles. The statistical association between HLA allelic frequency and disease severity was examined. The disease severity was categorized based on the length of hospital stay and intensive care needs or demise during the hospital stay.Results: HLA allelic frequencies of the high and low-severity cohorts were normalized against corresponding background allelic frequencies. In the high-severity cohort, A*02:06 (11.8-fold), B*51:01 (2.4-fold), B*15:01 (3.1-fold), C*01:02 (3.3-fold), DRB1*08:02 (31.2-fold), DQ*06:09 (11-fold), and DPB1*04:02(4-fold) were sig-nificantly overrepresented (p < 0.05) making these deleterious alleles. In the low-severity cohort, A*24:02 (2.8-fold), B*35:01 (2.8-fold), DRB1*04:07 (5.3-fold), and DRB1*08:11 (22-fold) were found to be signifi-cantly overrepresented (p < 0.05) making these protective alleles. These above alleles interact with NK cell antiviral activity via the killer immunoglobulin-like receptors (KIR). The high-severity cohort had a higher predilection for HLA alleles associated with KIR subgroups; Bw4-80I (1.1-fold), and C1 (1.6-fold) which pro-motes NK cell inhibition, while the low-severity cohort had a higher predilection for Bw4-80T (1.6-fold), and C2 (1.6-fold) which promote NK cell activation.Conclusion: In this study, the HLA allelic repository with the distribution of deleterious and protective alleles was found to correlate with the severity of the clinical course in COVID-19. Moreover, the interaction of speci-fic HLA alleles with the KIR-associated subfamily modulates the NK cell-mediated surveillance of SARS-CoV-2. Both deleterious HLA alleles and inhibitory KIR appear prominently in the severe COVID-19 group focusing on the importance of NK cells in the convalescence of COVID-19.

Antiplatelet therapy (APT) is the foundation of treatment and prevention of atherothrombotic events in patients with atherosclerotic cardiovascular disease. Selecting the optimal APT strategies to reduce major adverse cardiovascular events, while balancing bleeding risk, requires ongoing review of clinical trials. Appended, the focused update of the Canadian Cardiovascular Society/Canadian Association of Interventional Cardiology guidelines for the use of APT provides recommendations on the following topics: (1) use of acetylsalicylic acid in primary prevention of atherosclerotic cardiovascular disease; (2) dual APT (DAPT) duration after percutaneous coronary intervention (PCI) in patients at high bleeding risk; (3) potent DAPT (P2Y12 inhibitor) choice in patients who present with an acute coronary syndrome (ACS) and possible DAPT de-escalation strategies after PCI; (4) choice and duration of DAPT in ACS patients who are medically treated without revascularization; (5) pretreatment with DAPT (P2Y12 inhibitor) before elective or nonelective coronary angiography; (6) perioperative and longer-term APT management in patients who require coronary artery bypass grafting surgery; and (7) use of APT in patients with atrial fibrillation who require oral anticoagulation after PCI or medically managed ACS. These recommendations are all on the basis of systematic reviews and meta-analyses conducted as part of the development of these guidelines, provided in the Supplementary Material.

ST-segment elevation myocardial infarction (STEMI) complicating COVID-19 is associated with an increased risk of cardiogenic shock and mortality. However, little is known about the frequency of use and clinical impact of mechanical circulatory support (MCS) in these patients. We sought to define patterns of MCS utilization, patient characteristics, and outcomes in patients with COVID-19 with STEMI. The NACMI (North American COVID-19 Myocardial Infarction) is an ongoing prospective, observational registry of patients with COVID-19 positive (COVID-19+) with STEMI with a contemporary control group of persons under investigation who subsequently tested negative for COVID-19 (COVID-19-). We compared the baseline characteristics and in-hospital outcomes of COVID-19+ and patients with COVID-19- according to the use of MCS. The primary outcome was a composite of in-hospital mortality, stroke, recurrent MI, and repeat unplanned revascularization. A total of 1,379 patients (586 COVID-19+ and 793 COVID-19-) enrolled in the NACMI registry between January 2020 and November 2021 were included in this analysis; overall, MCS use was 12.3% (12.1% [n = 71] COVID-19+/MCS positive [MCS+] vs 12.4% [n = 98] COVID-19-/MCS+). Baseline characteristics were similar between the 2 groups. The use of percutaneous coronary intervention was similar between the groups (84% vs 78%; p = 0.404). Intra-aortic balloon pump was the most frequently used MCS device in both groups (53% in COVID-19+/MCS+ and 75% in COVID-19-/MCS+). The primary outcome was significantly higher in COVID-19+/MCS+ patients (60% vs 30%; p = 0.001) because of very high in-hospital mortality (59% vs 28%; p = 0.001). In conclusion, patients with COVID-19+ with STEMI requiring MCS have very high in-hospital mortality, likely related to the significantly higher pulmonary involvement compared with patients with COVID-19- with STEMI requiring MCS.

Background:In-hospital mortality in patients with ST-segment elevation myocardial infarction (STEMI) is higher in those with COVID-19 than in those without COVID-19. The factors that predispose to this mortality rate and their relative contribution are poorly understood. This study developed a risk score inclusive of clinical variables to predict in-hospital mortality in patients with COVID-19 and STEMI. Methods:Baseline demographic, clinical, and procedural data from patients in the North American COVID-19 Myocardial Infarction registry were extracted. Univariable logistic regression was performed using candidate predictor variables, and multivariable logistic regression was performed using backward stepwise selection to identify independent predictors of in-hospital mortality. Independent predictors were assigned a weighted integer, with the sum of the integers yielding the total risk score for each patient. Results:In-hospital mortality occurred in 118 of 425 (28%) patients. Eight variables present at the time of STEMI diagnosis (respiratory rate of >35 breaths/min, cardiogenic shock, oxygen saturation of <93%, age of >55 ​years, infiltrates on chest x-ray, kidney disease, diabetes, and dyspnea) were assigned a weighted integer. In-hospital mortality increased exponentially with increasing integer risk score (Cochran-Armitage χ2, P ​< ​.001), and the model demonstrated good discriminative power (c-statistic ​= ​0.81) and calibration (Hosmer-Lemeshow, P ​= ​.40). The increasing risk score was strongly associated with in-hospital mortality (3.6%-60% mortality for low-risk and very high-risk score categories, respectively). Conclusions:The risk of in-hospital mortality in patients with COVID-19 and STEMI can be accurately predicted and discriminated using readily available clinical information.

Background:Important health care differences exist between the United States (US) and Canada, which may have been exacerbated during the pandemic. We compared clinical characteristics, treatment strategies, and clinical outcomes of patients with ST-segment elevation myocardial infarction (STEMI) and COVID-19 (STEMI-COVID) treated in the US and Canada.Methods:The North American COVID-19 Myocardial Infarction registry is a prospective, investigator-initiated study enrolling patients with STEMI with confirmed or suspected COVID-19 in the US and Canada. The primary end point was in-hospital mortality. Additionally, we explored associations between vaccination and clinical outcomes.Results:Of 853 patients with STEMI-COVID, 112 (13%) were enrolled in Canada, and compared with the US, patients in Canada were more likely to present with chest pain and less likely to have a history of heart failure, stroke/transient ischemic attack, pulmonary infiltrates or renal failure. In both countries, the primary percutaneous coronary intervention was the dominant reperfusion strategy, with no difference in door-to-balloon times; fibrinolysis was used less frequently in the US than in Canada. The adjusted in-hospital mortality was not different between the 2 countries (relative risk [RR], 1.0; 95% CI, 0.46-2.72; P = 1.0). However, the risk of in-hospital mortality was significantly higher in unvaccinated compared with vaccinated patients with STEMI-COVID (RR, 4.7; 95% CI, 1.7-11.53; P = .015).Conclusions:Notable differences in morbidities and reperfusion strategies were evident between patients with STEMI-COVID in the US compared with Canada. No differences were noted for in-hospital mortality. Vaccination, regardless of region, appeared to associate with a lower risk of in-hospital mortality strongly.

Current guidelines recommend hospital admission for patients who present to the emergency department (ED) with chest pain and are scored as intermediate risk for adverse outcomes based on the HEART score. While hospital admission for these patients allows for timely investigation and treatment, it is a resource-intensive process. This study examines whether intermediate HEART score patients can be safely managed on an outpatient basis through rapid access chest pain clinics. This retrospective observational study included all ED chest pain patients referred to rapid access clinics from January 2018 to April 2020 in Regina and Saskatoon, Saskatchewan. ED physician HEART scores were used in lieu of reviewer HEART scores when available. The primary outcome was the rate of major adverse coronary events (MACE), a composite measure of death, acute coronary syndrome, stroke, coronary angiography, and revascularization at 6 weeks in intermediate-risk patients. Secondary outcomes were the type of MACE, rate of MACE before rapid access clinic appointment and the most predictive component of the HEART score. There were 1989 ED referrals, of which 817 were for intermediate-risk patients. 9.3

Background Cardiac intensive care units were originally created in the prerevascularization era for the early recognition of ventricular arrhythmias following a myocardial infarction. Many patients with stable ST-segment-elevation myocardial infarction (STEMI) are still routinely triaged to cardiac intensive care units after a primary percutaneous coronary intervention (pPCI), independent of clinical risk or the provision of critical care therapies. The aim of this study was to determine factors associated with in-hospital adverse events in a hemodynamically stable, postreperfusion population of patients with STEMI. Methods and Results Between April 2012 and November 2019, 2101 consecutive patients with STEMI who received pPCI in the Vancouver Coastal Health Authority were evaluated. Patients were stratified into those with and without subsequent adverse events, which were defined as cardiogenic shock, in-hospital cardiac arrest, stroke, re-infarction, and death. Multivariable logistic regression models were used to determine predictors of adverse events. After excluding patients presenting with cardiac arrest, cardiogenic shock, or heart failure, the final analysis cohort comprised 1770 stable patients with STEMI who had received pPCI. A total of 94 (5.3%) patients developed at least one adverse event: cardiogenic shock 55 (3.1%), in-hospital cardiac arrest 42 (2.4%), death 28 (1.6%), stroke 21 (1.2%), and re-infarction 5 (0.3%). Univariable predictors of adverse events were older age, female sex, prior stroke, chronic kidney disease, and atrial fibrillation. There was no significant difference in reperfusion times between those with and without adverse events. Following multivariable adjustment, moderate to severe chronic kidney disease (creatinine clearance <44 mL/min; 13% of cohort) was associated with adverse events (odds ratio 2.24 [95% CI, 1.12-4.48]) independent of reperfusion time, age, sex, smoking status, hypertension, diabetes, and prior myocardial infarction/PCI/coronary artery bypass grafting. Conclusions Only 1 in 20 initially stable patients with STEMI receiving pPCI developed an in-hospital adverse event. Moderate to severe chronic kidney disease independently predicted the risk of future adverse events. These results indicate that the majority of patients with STEMI who receive pPCI may not require routine admission to a cardiac intensive care unit following reperfusion.