Occlusion Myocardial Infarction Research Articles

Safety of Nurse-Managed Inhaled Nitric Oxide During Critical Care Interfacility Transport.

Inhaled nitric oxide (iNO) is an advanced therapy typically managed by physicians and respiratory therapists in order to increase arterial oxygenation and decrease pulmonary arterial pressure. The Johns Hopkins Lifeline Critical Care Transportation Program (Lifeline) initiated a novel nurse-managed iNO protocol in order to optimize the oxygenation of critically ill patients during interfacility transport. This study was a retrospective chart review of adverse events associated with iNO initiation or continuation by Lifeline on patients transported from March 1, 2020, to August 1, 2022. Basic demographic data and adverse events were recorded. Recorded adverse events included hypotension defined as a mean arterial pressure (MAP) < 65 mm Hg, hypoxemia defined as a decrease of ≥ 10% arterial oxygenation saturation measured by pulse oximetry, new bradycardia or tachyarrhythmia, nitrogen dioxide (NO2) levels greater than 1.0 ppm, methemoglobinemia, and cardiac arrest. Fifteen patients were diagnosed with SARS-CoV-2 infection, of which one also had pulmonary emboli, 2 had bacterial pneumonia, 1 suffered cardiogenic shock from occlusive myocardial infarction and were on VA-ECMO, and 2 had significant thoracic trauma resulting in pulmonary contusions and hemopneumothorax. iNO was continued on 10 patients and initiated on 8 patients, 2 of whom were transitioned from inhaled epoprostenol. Hypotension occurred in 3 (16.7%) patients and one (5.56%) of the hypotensive patients subsequently went on to experience new atrial fibrillation with vasopressor titration. No patients developed worsening hypoxemia, elevated NO2 levels, methemoglobinemia, or suffered cardiac arrest. All 3 patients who experienced hypotension were already on vasopressor support and the hypotension resolved with medication titration. This study shows that iNO administration can be safely managed by appropriately trained nurses.

A-35 | Is it Time for a Paradigm Shift Towards Occlusion Myocardial Infarction?

A-35 | Is it Time for a Paradigm Shift Towards Occlusion Myocardial Infarction?

Collagen matricryptin promotes cardiac function by mediating scar formation

AimsA peptide mimetic of a collagen-derived matricryptin (p1159) was shown to reduce left ventricular (LV) dilation and fibrosis after 7 days delivery in a mouse model of myocardial infarction (MI). This suggested p1159 long-term treatment post-MI could have beneficial effects and reduce/prevent adverse LV remodeling. This study aimed to test the potential of p1159 to reduce adverse cardiac remodeling in a chronic MI model and to elucidate p1159 mode-of-action. Materials and methodsUsing a permanent occlusion MI rodent model, animals received p1159 or vehicle solution up to 28 days. We assessed peptide treatment effects on scar composition and structure and on systolic function. To assess peptide effects on scar vascularization, a cohort of mice were injected with Griffonia simplicifolia isolectin-B4. To investigate p1159 mode-of-action, LV fibroblasts from naïve animals were treated with increasing doses of p1159. Key findingsMatricryptin p1159 significantly improved systolic function post-MI (2-fold greater EF compared to controls) by reducing left ventricular dilation and inducing the formation of a compliant and organized infarct scar, which promoted LV contractility and preserved the structural integrity of the heart. Specifically, infarcted scars from p1159-treated animals displayed collagen fibers aligned parallel to the epicardium, to resist circumferential stretching, with reduced levels of cross-linking, and improved tissue perfusion. In addition, we found that p1159 increases cardiac fibroblast migration by activating RhoA pathways via the membrane receptor integrin α4. SignificanceOur data indicate p1159 treatment reduced adverse LV remodeling post-MI by modulating the deposition, arrangement, and perfusion of the fibrotic scar.

Inferior Subtle ST Elevation. Would You Activate Cardiac Catheterization Laboratory?

BackgroundAccording to guidelines, patients with inferior myocardial infarction only qualify for emergent reperfusion if they have at least 1 mm of ST elevation in two contiguous inferior leads. Although this has remained the standard for years, acute coronary occlusion may occur in patients with nondiagnostic ST elevation. Accordingly, a paradigm change is instigated, shifting the focus to physiopathology (occlusion myocardial infarction) rather than ST criteria. Case ReportA middle-aged man presented to our emergency department with chest pain and subtle nondiagnostic electrocardiography (ECG) changes in inferior leads. A careful examination of aVL to detect ST depression in this lead was the key to successfully diagnosing occlusion myocardial infarction, allowing early revascularization of an occluded right coronary artery. Why Should an Emergency Physician Be Aware of This?Accurate diagnosis of coronary occlusion by means of ECG can be challenging in certain situations, as acute myocardial ischemia may occur in patients with nondiagnostic ST elevation, especially in the inferior leads. A thorough examination of aVL searching for ST depression is essential in these situations.

Occlusive myocardial infarction - emerging paradigm of acute coronary syndromes.

Occlusive myocardial infarction - emerging paradigm of acute coronary syndromes.

Okluzija u dominantnom levom koronarnom sistemu - EKG dilema u radu lekara hitne pomoći

Introduction/Objective Acute chest pain is the main clinical manifestation of acute coronary syndrome. A posterior myocardial infarction (MI) most commonly occurs as a complication or extension of an inferior MI because of the overlapping coronary vascularization. We are presenting a case in which the patient exhibited mild anginal symptoms and an ECG pattern which did not correlate with a devastating infarction. Case report: The Emergency Medical Team (EMT) was dispatched at 5 am to help a 62-year-old patient, who had been woken from his sleep by a feeling of tightness in his chest and weakness in both arms. Upon examination, the patient was hypertensive (160/90 mmHg) and moderately bradycardic (58-62/min), with normal oxygen saturation on room air (SaO2 98%). His prehospital ECG findings were as follows: sinus rhythm, horizontal ST depression in V1-V3 1 to 2mm, ST elevation ≤1mm in lead V6, subtle ST depression in D1 and aVL &lt;1mm, ST elevation in D3 and aVF &lt;1mm. After attaching additional posterior leads, the modified ECG recording showed an ST elevation of 1 to 2 mm in V7-V9. Continuous laboratory monitoring of cardiac enzyme markers showed elevated and increasing values: Troponin T -2377, 3756 ng/l; CK -1572, 1564 U/l. Coronary angiography: The LCA system was dominant. The RCA was nondominant with a 70-80% stenosis, and a complete Occlusion Myocardial Infarction (OMI) distally. Using the most accurate LCxc/RCA occlusion algorithms, the ECG finding suggested an occlusion in the right dominant coronary system, which does not correlate with the coronary angiography report. Conclusion: Excellent knowledge of recording, analysis, and interpretation of ECG tracings, facilitates adequate pre-hospital care and precise planning for further processing of patients with chest pain. It is recommended to record posterior and right unipolar leads in all patients with inferior and suspicion of posterior myocardial infarctions and to include the ST-elevation myocardial infarction equivalent into the STEMI network. Given the physiological differences in left ventricular vascularization and the possible predominance of the left coronary system over the right, future studies must focus on establishing more precise algorithms for assessing RCA/LCx occlusion.

Beyond the ST-segment in Occlusion Myocardial Infarction (OMI): Diagnosing the OMI-nous.

The ST-segment elevation (STE) myocardial infarction (MI)/non-STEMI (NSTEMI) paradigm has been the central dogma of emergency cardiology for the last 30 years. Although it was a major breakthrough when it was first introduced, it is now one of the most important obstacles to the further progression of modern MI care. In this article, we trace why a disease with an established underlying pathology (acute coronary occlusion [ACO]) was unintentionally labeled with a surrogate electrocardiographic sign (STEMI/NSTEMI) instead of pathologic substrate itself (ACO-MI/non-ACO-MI or occlusion MI [OMI]/non-OMI [NOMI] for short), how this fundamental mistake caused important clinical consequences, and why we should change this paradigm with a better one, namely OMI/NOMI paradigm.

Abstract OEC102: Unbiased Discovery Of Allograft Inflammatory Factor 1 As A New And Critical Immunometabolic Regulatory Node During Cardiac Injury

Introduction: Myocardial infarction (MI) mobilizes macrophages, which are the central protagonists of tissue repair in the infarcted heart. While macrophages are necessary for repair after MI, they can also contribute to adverse remodeling and progression to heart failure. We sought to identify novel mediators of maladaptive macrophage responses by performing single cell RNA sequencing of a patient with ischemic cardiomyopathy. This led to the unbiased identification of Allograft inflammatory factor 1 ( AIF1 ) as the most significant differentially expressed gene in macrophages compared to other cardiac cells during human heart failure. Hypothesis: Since AIF1 was specifically expressed in macrophages during ischemic heart failure, we next tested the hypothesis that AIF1 promoted maladaptive macrophage responses after MI. Methods and Results: Using autopsy samples from human acute MI patients or a murine model of permanent occlusion MI, we found that AIF1 was increased in macrophages, but not neutrophils or monocytes, after MI. To test the functional significance of AIF1 expression in macrophages after MI, we generated bone marrow chimeric mice where Aif1 -deficiency was restricted to only cells of hematopoietic origin. Despite comparable levels of surgically induced injury, loss of Aif1 was associated with increased proreparative macrophages, smaller infarct sizes, and preservation of cardiac function compared to wild-type controls. Therapeutic targeting of Aif1 with anti-sense oligonucleotides also conferred cardioprotective responses after MI. Mechanistically, AIF1 promoted actin polymerization in bone marrow-derived macrophages after TLR4 stimulation leading to increased glycolytic metabolism and inflammatory IL-6 and TNF-α production. AIF1 also suppressed calcium uptake in the mitochondria to limit mitochondrial metabolism and anti-inflammatory IL-10 production. Conclusion: These data newly reveal a proinflammatory role for AIF1 in the infarcted heart through inflammatory glycolytic reprogramming of macrophages, which required both calcium mobilization and actin polymerization. Targeted knockdown of AIF1 led to cardioprotection supporting further exploration of macrophage AIF1 as a therapeutic target after MI.

Point-of-care ultrasound may expedite diagnosis and revascularization of occult occlusive myocardial infarction

BackgroundElectrocardiographically occult occlusive myocardial infarction (OOMI), defined as coronary artery occlusion requiring revascularization without ST-segment elevation on electrocardiogram (ECG), is associated with delayed diagnosis resulting in higher morbidity. Left ventricular (LV) wall motion abnormalities (WMA) appreciated on echocardiography can expedite OOMI diagnosis. We sought to determine whether point-of-care ultrasound (PoCUS) demonstrating WMA expedites revascularization time when performed on emergency department patients being evaluated for OOMI. MethodsThis was a single-site retrospective cohort study over a 38-month period. All admitted adult ED patients ≥35 years of age evaluated by the emergency physician with PoCUS for LV function, an ECG, and a standard troponin I biomarker assay were included. Patients with ST-segment elevation myocardial infarction (STEMI), prior LV dysfunction, fever ≥100.4 °F, or hypotension were excluded. A structured chart abstraction was performed for relevant demographic and clinical characteristics. ResultsWe screened 1561 ED patients who underwent cardiac PoCUS for eligibility: 874 met exclusion criteria, 453 were discharged, and 234 were included in the analysis. Twenty-three patients had coronary interventions, of which 14 had WMA. PoCUS was performed 36 min (IQR −9–68) before troponin resulted (n = 234) and 39 min (IQR −23–96) before the first troponin elevation (n = 85). Twenty of the 23 patients diagnosed with OOMI had elevated troponins prior to catheterization with time from PoCUS to first troponin elevation of 43 min (IQR 9–263). Of these patients, 11 had WMA identified on PoCUS, and the WMA was appreciated 47 min (IQR 26–255) prior to troponin elevation. The time from ED arrival to revascularization was 673 min (IQR 251–2158); 432 min (IQR 209–1300) among patients with WMA (n = 14) compared with 2158 min (IQR 552–3390) for those without WMA (n = 9). ConclusionCardiac PoCUS may identify OOMI earlier than standard evaluation and may expedite definitive management.

Pulsed Field Ablation of Left Ventricular Myocardium in a Swine Infarct Model.

Pulsed field ablation (PFA) leads to cell death by irreversible electroporation. There are limited data about PFA lesion characteristics in the ventricle, particularly in the presence of myocardial scar. This study sought to evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted left ventricular (LV) myocardium in swine. Swine (n=10) underwent either: 1) 120-minute left anterior descending coronary artery balloon occlusion myocardial infarction and survived for 6 to 8weeks (n=8); or 2) served as healthy control subjects (n=2). PFA or RFA was delivered to the LV endocardium in regions of healthy myocardium or scar identified with electroanatomical mapping. Bipolar, biphasic PFA was delivered for 2.5 seconds× 4 applications/site using 2 different catheters: linear quadripolar (FOCAL) or multispline 8-pole catheter (BASKET). Gross and histologic measurements of lesion size were performed. In the PFA group, 21 lesions were delivered to healthy LV and 20 to areas of scar. Overall, there was no significant difference in lesion depth between catheter groups (FOCAL linear vs BASKET; P = 0.740), whereas lesion width was greater for BASKET (10.6 ± 2.4mm vs 13.3 ± 3.3mm; P = 0.007). In myocardial scar, lesion depth was not significantly different between PFA catheters (P = 0.235). However, lesion depth for PFA was greater than for RFA (PFAvs RFA; 6.1 ± 1.7mm vs 3.8 ± 1.7mm; P = 0.005). PFA allows rapid, safe, and effective ablation of surviving islands of myocardium within and around infarcted LV substrate. This technology holds promise for treating infarct-related ventricular tachycardia in humans.

CA-534-01 PULSED FIELD ABLATION COMPARED TO RADIOFREQUENCY ABLATION OF LEFT VENTRICULAR MYOCARDIUM IN A SWINE INFARCT MODEL

There is limited data on use of pulsed field ablation (PFA) in the left ventricle (LV), particularly in the presence of myocardial scar To evaluate the lesion characteristics of PFA and radiofrequency energy (RFA) in healthy and infarcted LV myocardium 10 swine were included: 8 underwent 120min LAD balloon occlusion myocardial infarction and were survived for 6-8 weeks; 2 were healthy controls. PFA and standard RFA was delivered to the LV endocardium in healthy myocardium or scar identified with electroanatomic mapping. Bipolar, biphasic PFA was delivered at 1800 to 2000V for 2.5secs x 4 applications/site using 2 different catheters: linear quadripolar (LINEAR) or multi-spline 8-pole catheter (BASKET). Irrigated RF energy was delivered from 35W-50W to achieve >10 ohm impedance drop. Detailed histologic measurements of ablation depth were performed. In the PFA group, 21 lesions were delivered to healthy LV and 20 to scar, all without complications. There was no significant difference in histologic lesion depth in healthy myocardium or scar between LINEAR vs. BASKET PFA catheters (Figure A). In the RF group, 19 lesions were delivered to healthy LV and 8 to scar. Maximal lesion depth for PFA and RFA were similar in healthy tissue, however lesion depth was greater for PFA than RFA in scar (Figure B, 6.1±1.7 vs 3.8±1.7 mm; P=0.005). There was no vascular injury observed with PFA, however RFA led to adventitial edema and thrombosis. PFA allows rapid, safe and effective ablation of surviving islands of myocardium within infarcted LV substrate. Lesion depth in myocardial scar is greater for PFA than RFA. This technology holds promise for treating infarct-related ventricular tachycardia in humans.

A nurse-led pre-hospital triage service for identifying patients with occlusive myocardial infarction: a service evaluation

Background/Aims Acute coronary syndromes include unstable angina and myocardial infarction, of which occlusive myocardial infarction is a high-risk subset that is often missed because of a lack of ST elevation. Pre-hospital electrocardiograms may be able to identify myocardial infarction early and reduce mortality. However, it is unclear whether pre-hospital electrocardiograms can accurately detect occlusive myocardial infarction and how this affects outcomes. This study will analyse the outcomes of patients with occlusive myocardial infarction who had a pre-hospital electrocardiogram. Method Electrocardiograms transmitted to the coronary care unit triage service were identified, along with data regarding patient demographics, referrals and mortality. Data were analysed for correlations between demographic and clinical factors and type of myocardial infarction. Results A total of 838 electrocardiograms were identified; 69 (8.2%) showed myocardial infarction and eight (1.0%) showed occlusive myocardial infarction, of which 50% had ST elevation. Patients with occlusive myocardial infarction were more likely to be triaged to the coronary care unit than patients with non-occlusive myocardial infarction (P=0.04). However, 38 (55.1%) of the patients with myocardial infarction and four (50.0%) of the patients with occlusive myocardial infarction were not directed to a coronary care unit or the catheterisation laboratory. Patients with occlusive myocardial infarction had higher index episode mortality rates (P=0.03) and 30-day mortality rates (P&lt;0.01). Conclusions Despite pre-hospital electrocardiogram transmission and adherence to the guidelines, triage of myocardial infarction and occlusive myocardial infarction is imperfect. Refinement of risk scores and adaptation of new technology is required to help identify patients with occlusive myocardial infarction so they can be prioritised for immediate reperfusion therapy.

Using latent class analysis to identify clinical features of patients with occlusive myocardial infarction: Preangiogram prediction remains difficult.

BackgroundTreatment decisions in myocardial infarction (MI) are currently stratified by ST elevation (ST‐elevation myocardial infarction [STEMI]) or lack of ST elevation (non‐ST elevation myocardial infarction [NSTEMI]) on the electrocardiogram. This arose from the assumption that ST elevation indicated acute coronary artery occlusion (OMI). However, one‐quarter of all NSTEMI cases are an OMI, and have a higher mortality. The purpose of this study was to identify features that could help identify OMI.MethodsProspectively collected data from patients undergoing percutaneous coronary intervention (PCI) was analyzed. Data included presentation characteristics, comorbidities, treatments, and outcomes. Latent class analysis was undertaken, to determine patterns of presentation and history associated with OMI.ResultsA total of 1412 patients underwent PCI for acute MI, and 263 were diagnosed as OMI. Compared to nonocclusive MI, OMI patients are more likely to have fewer comorbidities but no difference in cerebrovascular disease and increased acute mortality (4.2% vs. 1.1%; p < .001). Of OMI, 29.5% had delays to their treatment such as immediate reperfusion therapy. With latent class analysis, while clusters of similar patients are observed in the data set, the data available did not usefully identify patients with OMI compared to non‐OMI.ConclusionFeatures between OMI and STEMI are broadly very similar. However, there was no difference in age and risk of cerebrovascular disease in the OMI/non‐OMI group. There are no reliable characteristics therefore for identifying OMI versus non‐OMI. Delays to treatment also suggest that OMI patients are still missing out on optimal treatment. An alternative strategy is required to improve the identification of OMI patients.

From Q/Non-Q Myocardial Infarction to STEMI/NSTEMI: Why It's Time to Consider Another Simplified Dichotomy; a Narrative Literature Review.

Acute coronary syndromes (ACSs) are classified as ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) based on the presence of guideline-recommended ST-segment elevation (STE) criteria on the electrocardiogram (ECG). STEMI is associated with acute total coronary occlusion (ATO) and transmural myocardial necrosis and is managed with emergent reperfusion therapy, and NSTEMI is supposedly synonymous with subendocardial myocardial infarction without ATO. However, coronary angiograms reveal that a significant proportion of patients with NSTEMI have ATO. Here, we review articles that studied the frequency and cardiovascular outcomes of ATO in NSTEMI patients compared with those without ATO. We discuss ECG patterns of patients with suspected acute myocardial infarction that do not fulfill STEMI criteria but are associated with ATO. Under-recognition of these atypical patterns results in delays to reperfusion therapy. We also advocate revision of the current STEMI/NSTEMI paradigm because consideration of STE, by itself, out of context of other clinical and ECG features, leads to the ECG diagnosis of STEMI when the ECG actually represents a mimic ["Pseudo-STEMI"],and suggest renaming the ACSs classification as the Occlusion Myocardial Infarction (OMI)/Non-Occlusion Myocardial Infarction (NOMI) paradigm.

Acute Occlusion of the Infarct-Related Artery as a Predictor of Very Long-Term Mortality in Patients with Acute Myocardial Infarction.

Aim The survey's aim was to examine the significance of infarct-related artery (IRA) occlusion (verified angiographically) on very long-term outcomes of patients with acute myocardial infarction, within the STEMI and NSTEMI diagnosis. Methods A single-center, nonrandomized, registry-based study on patients treated for acute coronary syndrome with percutaneous coronary intervention between June 2011 and December 2016 was conducted. Patients with angiographically proven IRA occlusion (100% stenosis with TIMI flow 0 distal to occlusion) were categorized as occlusive myocardial infarction (OMI) and patients with patent IRA (50–99% stenosis with TIMI 1–3 flow) were categorized as nonocclusive myocardial infarction (NOMI) and very long-term outcomes were analyzed. Data were collected prospectively from the hospital's PCI registry and the database of the Croatian Institute of Public Health. Results A total of 2450 patients were included in the study. 796 (32.5%) patients had NOMI and 1654 patients (67.5%) had OMI. According to ECG changes, 1534 patients presented with STEMI (62,6%) and 916 with NSTEMI (37,8%). 88% of STEMI patients presented with OMI and 12% with NOMI, while patients with NSTEMI in 33,8% presented with OMI and in 66,81% with NOMI. A median follow-up was 4.7 years. There was no significant difference in cardiovascular mortality between the groups (14.8% vs 13.1%; OMI vs NOMI, respectively; p=0.374) neither in all-cause mortality (19% vs 21.5%; OMI vs NOMI, respectively; p=0.374). Patients with NSTEMI had a significantly higher very long-term mortality (21.6% vs 18.1%; NSTEMI vs STEMI, respectively; p=0.029). Conclusion The main findings of the study are as follows: (1) total IRA occlusion was not associated with higher long-term mortality; (2) NSTEMI was associated with a higher mortality rate compared with STEMI, independent of angiographic presentation (OMI/NOMI); (3) IRA occlusion was not associated with significantly higher mortality rates in patients with STEMI and NSTEMI, respectively.

Diagnosis of Occlusion Myocardial Infarction in Patients with Left Bundle Branch Block and Paced Rhythms

A number of criteria have been developed to aid with the diagnosis of occlusion myocardial infarction (OMI) in patients with left bundle branch block (LBBB) and ventricular paced rhythms (VPR). The current guidelines do not provide clear preference for any specific ECG criteria in LBBB and paced rhythm patients. This review delineates the difficulties of electrocardiographic diagnosis of OMI in both LBBB and VPR patients. We describe the original Sgarbossa and the newer criteria and their diagnostic performances. We highlight the expected changes of newer pacing modalities and how they may interfere with the electrocardiographic diagnosis of OMI. We recommend utilizing the Cai et al. algorithm, which combines clinical assessment with the SmithModified Sgarbossa ECG criteria, for both LBBB and right ventricular pacing patients with suspected OMI. There is limited data concerning ECG changes of OMI in patients with the newer pacing modalities, such as biventricular, His-bundle, or left bundle branch pacing.

Identification of the characteristics of occlusive myocardial infarction: are there any tell-tale signs?

Abstract Introduction Treatment urgency of myocardial infarction (MI) is currently stratified by ST elevation (STEMI) or lack of ST elevation (NSTEMI) on the electrocardiogram. This categorisation arose from the theory that ST elevation indicated total acute coronary artery occlusion (1). However, one-quarter of all NSTEMI have acute occlusion, have a higher mortality and are potentially missed by this strategy (2). Purpose The study purpose is to identify clinical features that could help distinguish an occlusive MI from non-occlusive MI. Methods The prospectively British Cardiovascular Intervention Society (BCIS) data set was collected from patients undergoing primary cutaneous intervention (dataset) was analysed from the years 2015 to 2019. Data collected included presentation characteristics, co-morbidities, treatments and outcomes. We further undertook latent class analysis, to determine whether distinct patterns of presentation and history are associated with acutely occluded NSTEMI. This methodology proceeds through segmentation of a dataset into clusters (“classes”) based on case similarities for the set of variables or “indicators” of interest; the classes are then statistically analysed to evaluate the differences between them. Results A total of 2025 patients underwent percutaneous coronary intervention (PCI) between 2015 and 2019. Of these, 1412 underwent PCI for MI, 510 had a STEMI, and 263 had occlusive MI on angiogram. STEMI patients tended to be younger (66 vs 67; p=0.045), in shock (6.1% vs 1.9%; p&amp;lt;0.001), have cardiac arrest (5.7% vs 1.2%; p&amp;lt;0.001), less co-morbidities, increased left ventricular ejection fraction (LVEF) (&amp;lt;30% 11.8% vs 4.7%; p&amp;lt;0.001, increased short-term mortality (3.5% vs 0.7%; p&amp;lt;0.001) and increased emergency PCI (55.9% vs 6.9%; p&amp;lt;0.001) and thrombolysis (32.7% vs 2.5%; p&amp;lt;0.001),. Occlusive MI patients tended to have ST elevation (63.5% vs 29.9%: p&amp;lt;0.001), cardiogenic shock (9.1% vs 2.1%; p&amp;lt;0.001) cardiac arrest (5.3% vs 2.3%; p=0.007), less co-morbidities but no difference in cerebrovascular disease, increased acute mortality (4.2% vs 1.1%; p&amp;lt;0.001) severe LVEF (11.8% vs 6.2%; p&amp;lt;0.001) and increased emergency PCI (70.3% vs 14.1%; p&amp;lt;0.001), With latent class analysis, while clusters of similar patients are observed in the dataset, we determined that the variables captured by BCIS do not usefully indicate an acutely occluded MI compared to non-occlusive MI (Figure 1). Conclusion Features between occlusive MI and STEMI are broadly very similar. However, unlike STEMI/NSTEMI, there was no difference in age and risk of cerebrovascular disease in the occlusive MI/non-occlusive MI group. This could indicate occlusion MI occurs in higher numbers in elderly and frail patients and may be frequently missed, possibly from greater collateralisation. There is no reliable characteristic for identifying occlusive between non-occlusive MI. Improved methods are needed for the identification of occlusive MI patients. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): A project supported by the European Union's INTERREG VA Programme, managed by the Special EU Programmes Body (SEUPB). The funders of this project had no input in designing, implementation or writing of this review. Step 1 of latent class analysis

New concept: occlusion (OMI) and non-occlusion myocardial infarction (NOMI)

The article deals with an important problem of managing patients with myocardial infarction (MI). It’s known that the greatest benefit of immediate invasive intervention obtains patients with acute occlusion of the coronary arteries (or subocclusion). However, numerous studies have shown that up to 30 % of patients classified as non-ST segment elevation myocardial infarction (NSTEMI) are consistently found to have missed acute coronary occlusion. At that time, a number of patients with «benign» ST elevation undergo unnecessary catheterisation +/- reperfusion therapy that increases the risk of complications. In 2018 Meyers P., Weingart S. and Smith S. noted that ST elevation on ECG is most likely an unreliable tool for detecting patients that will benefit from immediate percutaneous coronary intervention (PCI) and that a shift is required to a more reliable paradigm for detecting acute coronary occlusion, than the concept ST-elevation myocardial infarction. The authors introduced us to the new concept of Occlusion Myocardial Infarction (OMI) and Non-Occlusion Myocardial Infarction (NOMI). In this article we discuss five examples of ECG with occlusive myocardial infarction (OMI).

Recognizing electrocardiographically subtle occlusion myocardial infarction and differentiating it from mimics: Ten steps to or away from cath lab.

It is increasingly evident that the ST-segment elevation (STE) myocardial infarction (MI)/non-STEMI paradigm that equates STEMI with acute coronary occlusion (ACO) is deceptive. This unfortunate paradigm, adhered to by the current guidelines, misses at least one-fourth of the ACOs, and unnecessarily over-triages a similar fraction of the patients to the catheterization laboratory. Accordingly, we have been calling for a new paradigm, the occlusion/nonocclusion MI (OMI/NOMI). Although this new OMI/NOMI paradigm is not limited to an electrocardiogram (ECG), the ECG will remain the cornerstone of this new paradigm because of its speed, repeatability, noninvasive nature, wide availability, and high diagnostic power for OMI. This review provides a step-by-step approach to ECG for the diagnosis of OMI.

B-AB03-03 PULSED FIELD ABLATION OF LEFT VENTRICULAR MYOCARDIUM IN A SWINE INFARCT MODEL

Pulsed field ablation (PFA) leads to cell death by irreversible electroporation. However, there is limited data about lesion characteristics in ventricular myocardium in the presence of myocardial scar. To evaluate the lesion characteristics of PFA in healthy and infarcted left ventricular (LV) myocardium. Swine (n=6) underwent 120min LAD balloon occlusion myocardial infarction (MI) and were survived 6-8 weeks. PFA was delivered to the LV endocardium of 1) healthy myocardium or 2) MI identified with electroanatomic mapping. Bipolar, biphasic PFA was delivered for 2.5secs x 4 applications/site (10secs total) using 2 different catheters: a linear quadripolar (FOCAL, 2000-2100V) or multi-spline 8-pole catheter (BASKET, 1800V) (FARAPULSE, Menlo Park, CA) (Figure). After sectioning, gross lesions were identified, measured using calipers and tissue stained for histology. 21 lesions were delivered to healthy LV and 20 to areas with MI, all without complications. Overall, there was no significant difference in lesion depth between groups (FOCAL vs. BASKET; depth: 5.6 ±1.1 mm vs. 5.5 ± 1.1 mm, P=0.740), while lesion width was greater for BASKET (10.6 ± 2.4 mm vs. 13.3 ± 3.3 mm, P=0.007). In regions of MI, histology showed ablation of surviving myocardium both within and epicardial to scar; lesion depth in MI was not significantly different between catheters (5.6 ± 1.5 mm vs. 4.6 ± 0.9 mm; P=0.235). PFA allows rapid, safe, and effective ablation of surviving islands of myocardium within and around infarcted LV substrate. This technology holds promise for treating infarct-related ventricular tachycardia in humans.