Appropriate cardiac cath lab activation: optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction

Shortening Door-to-Balloon Time: The Use of Ambulance versus Private Vehicle for Patients with ST-Segment Elevation Acute Myocardial Infarction

Purpose

Time is critical when dealing with acute myocardial infarction (AMI) patients in the Emergency Department (ED), as 90 min is crucial for overall health. Using non-EMS transportation for critical patients, such as patients with acute myocardial infarction, to a hospital might delay the rapid identification of the underlying medical disease and initiating definitive treatment. We aim to evaluate the association between the mode of transportation and the D2B time in patients presenting at the ED with AMI.

Patients and Methods

We conducted a retrospective cohort study with patients who presented at ED with AMI and underwent percutaneous coronary intervention (PCI). The participants were patients with confirmed AMI at the ED of King Abdullah Medical City (KAMC) from January 2019 to December 2019.

Results

In total, 162 AMI patients were enrolled in the study and divided based on the method of transportation. Less than half (n=65, 40.1%) were transported with an ambulance and 97 (59.9%) patients with a private car. The door-to-balloon (D2B) time for the ambulance group was 93.6±38.31 minutes, and the private car group was 93.8±30.88 minutes.

Conclusion

There was no statistical significance when comparing the D2B time between the private car group and the ambulance group (P = 0.1870). Finally, ambulance transport significantly shortened the time to first ED physician contact. However, it was not associated with shortened D2B time when compared to private vehicle transport.

Missing occlusions: Quality gaps for ED patients with occlusion MI

BACKGROUND

ST-elevation Myocardial Infarction (STEMI) guidelines encourage monitoring of false positives (Code STEMI without culprit) but ignore false negatives (non-STEMI with occlusion myocardial infarction [OMI]). We evaluated the hospital course of emergency department (ED) patients with acute coronary syndrome (ACS) using STEMI vs OMI paradigms.

METHODS

This retrospective chart review examined all ACS patients admitted through two academic EDs, from June 2021 to May 2022, categorized as 1) OMI (acute culprit lesion with TIMI 0-2 flow, or acute culprit lesion with TIMI 3 flow and peak troponin I >10,000 ng/L; or, if no angiogram, peak troponin >10,000 ng/L with new regional wall motion abnormality), 2) NOMI (Non-OMI, i.e. MI without OMI) or 3) MIRO (MI ruled out: no troponin elevation). Patients were stratified by admission for STEMI. Initial ECGs were reviewed for automated interpretation of "STEMI", and admission/discharge diagnoses were compared.

RESULTS

Among 382 patients, there were 141 OMIs, 181 NOMIs, and 60 MIROs. Only 40.4% of OMIs were admitted as STEMI: 60.0% had "STEMI" on ECG, and median door-to-cath time was 103 min (IQR 71-149). But 59.6% of OMIs were not admitted as STEMI: 1.3% had "STEMI" on ECG (p < 0.001) and median door-to-cath time was 1712 min (IQR 1043-3960; p < 0.001). While 13.9% of STEMIs were false positive and had a different discharge diagnosis, 32.0% of Non-STEMIs had OMI but were still discharged as "Non-STEMI."

CONCLUSIONS

STEMI criteria miss a majority of OMI, and discharge diagnoses highlight false positive STEMI but never false negative STEMI. The OMI paradigm reveals quality gaps and opportunities for improvement.

Deploying a novel custom mobile application for STEMI activation and transfer in a large healthcare system to improve cross-team workflow. STEMIcathAID implementation project

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) is a high-risk patient medical emergency. We developed a secure mobile application, STEMIcathAID, to optimize care for STEMI patients by providing a digital platform for communication between the STEMI care team members, EKG transmission, cardiac catherization laboratory (cath lab) activation and ambulance tracking. The aim of this report is to describe the implementation of the app into the current STEMI workflow in preparation for a pilot project employing the app for inter-hospital STEMI transfer.

APPROACH

App deployment involved key leadership stakeholders from all multidisciplinary teams taking care of STEMI patients. The team developed a transition plan addressing all aspects of the health system improvement process including the workflow analysis and redesign, app installation, personnel training including user account access to the app, and development of a quality assurance program for progress evaluation. The pilot will go live in the Emergency Department (ED) of one of the hospitals within the Mount Sinai Hospital System (MSHS) during the daytime weekday hours at the beginning and extending to 24/7 schedule over 4-6 weeks. For the duration of the pilot, ED personnel will combine the STEMIcathAID app activation with previous established STEMI activation processes through the MSHS Clinical Command Center (CCC) to ensure efficient and reliable response to a STEMI alert. More than 250 people were provisioned app accounts including ED Physicians and frontline nurses, and trained on their user-specific roles and responsibilities and scheduled in the app. The team will be provided with a feedback form that is discipline specific to complete after every STEMI case in order to collect information on user experience with the STEMIcathAID app functionality. The form will also provide quantitative metrics for the key time sensitive steps in STEMI care.

CONCLUSIONS

We developed a uniform approach for deployment of a mobile application for STEMI activation and transfer in a large urban healthcare system to optimize the clinical workflow in STEMI care. The results of the pilot will demonstrate whether the app has a significant impact on the quality of care for transfer of STEMI patients.

Clinical validation of a 13-lead electrocardiogram derived from a self-applicable 3-lead recording for diagnosis of myocardial supply ischaemia and common non-ischaemic electrocardiogram abnormalities at rest

Aims

In this study, we compare the diagnostic accuracy of a standard 12-lead electrocardiogram (ECG) with a novel 13-lead ECG derived from a self-applicable 3-lead ECG recorded with the right exploratory left foot (RELF) device. The 13th lead is a novel age and sex orthonormalized computed ST (ASO-ST) lead to increase the sensitivity for detecting ischaemia during acute coronary artery occlusion.

Methods and results

A database of simultaneously recorded 12-lead ECGs and RELF recordings from 110 patients undergoing coronary angioplasty and 30 healthy subjects was used. Five cardiologists scored the learning data set and five other cardiologists scored the validation data set. In addition, the presence of non-ischaemic ECG abnormalities was compared. The accuracy for detection of myocardial supply ischaemia with the derived 12 leads was comparable with that of the standard 12-lead ECG (P = 0.126). By adding the ASO-ST lead, the accuracy increased to 77.4% [95% confidence interval (CI): 72.4-82.3; P < 0.001], which was attributed to a higher sensitivity of 81.9% (95% CI: 74.8-89.1) for the RELF 13-lead ECG compared with a sensitivity of 76.8% (95% CI: 71.9-81.7; P < 0.001) for the 12-lead ECG. There was no significant difference in the diagnosis of non-ischaemic ECG abnormalities, except for Q-waves that were more frequently detected on the standard ECG compared with the derived ECG (25.9 vs. 13.8%; P < 0.001).

Conclusion

A self-applicable and easy-to-use 3-lead RELF device can compute a 12-lead ECG plus an ischaemia-specific 13th lead that is, compared with the standard 12-lead ECG, more accurate for the visual diagnosis of myocardial supply ischaemia by cardiologists.

De Winter presentations and considerations: a case series

Background

The electrocardiogram has a critical role in the diagnosis and risk assessment of patients presenting with chest pain in the emergency ward.

Case presentation

We present 11 Iranian patients with diagnosis of de Winter referred to our center. Right coronary artery involvement was seen in four cases, left circumflex artery in three cases, proximal left anterior descending artery in two cases, and middle left anterior descending artery in seven cases. We present the case of a 52-year old Iranian male patient in detail.

Conclusion

Recognizing the electrocardiogram of de Winter as an ST-elevation myocardial infarction equivalent in cases with suspected acute infarction is very important.

Combining electrocardiographic criteria for predicting acute total left main coronary artery occlusion

Background

Prediction of left main artery (LM) occlusion may contribute to the administration of early reperfusion. We sought to identify electrocardiographic (ECG) features associated with acute total LM occlusion and explore the relationship between ECG features and collateral circulation.

Methods

We retrospectively studied ECGs in 84 consecutive patients with LM occlusion between January 2001 and April 2022. The ECG findings in these patients were compared with those in 468 consecutive patients with LM subtotal occlusion and non-LM occlusion.

Results

Three main ECG patterns were described according to the characteristics of ST elevation (STE) in LM occlusion: ST-segment elevation myocardial infarction (STEMI), STE in aVR with diffuse ST depression, and STE in both aVR and aVL. These ECG patterns were associated with different collateral filling territories. One-third STEMI in LM occlusion showed STE in the precordial leads including V1, while 2/3 STEMI showed STE in the precordial leads from V2 to V5 without STE in V1. The following ECG characteristics predicted LM occlusion: STE in both aVR and aVL; STE in I, aVL, and V2–V5 without V1; left anterior fascicular block (LAFB); right bundle branch block (RBBB) + LAFB; and prolongation of the QRS interval. The incidences of STE in aVR and STE in aVR and V1 were higher in LM subtotal occlusion than in LM occlusion. The combination of two different STE criteria (STE in aVR and aVL and STE in I, aVL, V2-V5 without V1) predicted LM occlusion with 62% sensitivity and 95% specificity. The combination of the STE criteria and fascicular block criteria (LAFB and LAFB + RBBB) further improved the specificity to 99% but reduced the sensitivity to 39%.

Conclusion

The combination of STE criteria predicted LM occlusion with high specificity and moderate sensitivity, and the addition of fascicular block criteria further improved the specificity with some loss of sensitivity.

Atypical de Winter Presentation of Critical Left Anterior Descending Coronary Artery Occlusion

A 69-year-old male presented with substernal chest pain that started a few hours earlier. On arrival, the patient was hemodynamically stable, and the physical examination was unrevealing. Laboratory workup revealed an elevated high-sensitivity troponin, and an initial electrocardiogram (ECG) revealed tall, symmetric T-waves with preceding minor concave ST-segment elevations less than 1 mm in the precordial leads (V1-V6) and 0.5 mm ST elevation in the aVR. Due to concerning ECG changes, the patient was treated for a possible non-ST-segment elevation myocardial infarction. A loading dose of aspirin and clopidogrel was given and a heparin drip was initiated. However, the patient's chest pain persisted requiring multiple sublingual nitroglycerin tablets. Later, on further review of the ECGs, the presence of de Winter T-waves was noted and led to activation of the catheterization laboratory, and an urgent left heart catheterization (LHC) was done. LHC revealed a critical 90% occlusion of the left anterior descending artery, and a drug-eluting stent was placed. The patient had a good recovery thereafter. This case emphasizes the rarity of the case and lack of awareness about the atypical de Winter pattern that is considered to be an ST-segment elevation myocardial infarction equivalent. Failure to recognize this can potentially lead to delayed intervention.

De Winter electrocardiogram pattern due to type A aortic dissection: a case report

Background

De Winter electrocardiograph (ECG) pattern is an atypical presentation of acute myocardial infarction (AMI) due to severe stenosis of the left anterior descending (LAD). Complications of acute aortic dissection (AD) in the setting of acute myocardial infarction (AMI) with de Winter sign are relatively rare and physicians may easily miss the diagnosis of AD. We report a case of patient with acute chest pain and de Winter ECG pattern due to AD involving the left main coronary artery (LM), LAD and left circumflex artery (LCX).

Case presentation

A 57-year-old male patient was initially diagnosed with AMI and then the diagnosis of acute AD was supported by transthoracic echocardiograph (TTE). After two stents were implanted respectively into the proximal LM-LAD and LM-LCX, he recovered from cardiogenic shock. Two months later, the patient underwent the surgery of ascending aorta replacement. After the surgery, there was no obvious chest discomfort during follow-up.

Conclusions

When an ECG shows a “de Winter pattern”, we should also consider the possibility of AD which result in LAD occlusion. TTE is a useful tool in screening for AD. Further research is needed to prove that percutaneous coronary intervention (PCI) may be a useful treatment strategy in the case of AD leading to severe LAD occlusion and unstable hemodynamics when there’s no condition to perform aortic replacement surgery immediately.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02596-8.

Electrocardiographic patterns predict the presence of collateral circulation and in-hospital mortality in acute total left main occlusion

Background

Data on the clinical characteristics, electrocardiogram (ECG) findings and outcomes of patients with acute myocardial infarction (AMI) due to total unprotected left main (ULM) artery occlusion is limited.

Methods

Between 2009 and 2021, 44 patients with AMI due to total ULM occlusion underwent primary percutaneous coronary intervention (PCI) at our institution. The ECG, collateral circulation, clinical and procedural characteristics, and in-hospital mortality were retrospectively evaluated.

Results

Twenty five patients presented with shock and 18 patients had in-hospital mortality. Nineteen patients presented with ST-segment elevation myocardial infarction (STEMI), while 25 presented with non-ST-segment elevation myocardial infarction (NSTEMI). ST-segment elevation (STE) in I and STEMI were associated with the absence of collateral circulation, while STE in aVR was associated with its presence. In the NSTEMI group, patients with STE in both aVR and aVL showed more collateral filling of the left anterior descending coronary artery (LAD) territory, while patients with STE in aVR showed more collateral filling of the LAD and the left circumflex artery territory. Compared with total ULM occlusion, patients with partial ULM obstruction presented with more STE in aVR, less STE in aVR and aVL, and less STEMI. Shock, post-PCI TIMI 0–2 flow, non-STE in aVR, STEMI, and STE in I predicted in-hospital mortality. STEMI and the absence of collateral flow were significantly associated with shock.

Conclusions

STE in the precordial leads predicted the absence of collateral circulation while STE in aVR and STE in both aVR and aVL predicted different collateral filling territories in ULM occlusion. STE in I, non-STE in aVR, and STEMI predicted in-hospital mortality in these patients.

Deep Learning Networks Accurately Detect ST-Segment Elevation Myocardial Infarction and Culprit Vessel

Early diagnosis of acute ST-segment elevation myocardial infarction (STEMI) and early determination of the culprit vessel are associated with a better clinical outcome. We developed three deep learning (DL) models for detecting STEMIs and culprit vessels based on 12-lead electrocardiography (ECG) and compared them with conclusions of experienced doctors, including cardiologists, emergency physicians, and internists. After screening the coronary angiography (CAG) results, 883 cases (506 control and 377 STEMI) from internal and external datasets were enrolled for testing DL models. Convolutional neural network-long short-term memory (CNN-LSTM) (AUC: 0.99) performed better than CNN, LSTM, and doctors in detecting STEMI. Deep learning models (AUC: 0.96) performed similarly to experienced cardiologists and emergency physicians in discriminating the left anterior descending (LAD) artery. Regarding distinguishing RCA from LCX, DL models were comparable to doctors (AUC: 0.81). In summary, we developed ECG-based DL diagnosis systems to detect STEMI and predict culprit vessel occlusion, thus enhancing the accuracy and effectiveness of STEMI diagnosis.

Rational and design of ST-segment elevation not associated with acute cardiac necrosis (LESTONNAC). A prospective registry for validation of a deep learning system assisted by artificial intelligence

BACKGROUND

Patients with chest pain and persistent ST segment elevation (STE) may not have acute coronary occlusions or serum troponin curves suggestive of acute necrosis. Our objective is the validation and cost-effectiveness analysis of a diagnostic model assisted by artificial intelligence (AI).

METHODS

Prospective multicenter registry in two groups of patients with STE: I) coronary arteries without significant lesions and without serum troponin curve suggestive of acute necrosis, II) myocardial infarction with acute coronary occlusion. The inclusion criteria are the following: 1) age ≥ 18 years, 2) chest pain or symptoms suggestive of myocardial ischemia, 3) STE at point J in two contiguous leads ≥0.1 mV, in V2 and V3 ≥ 0,2 mV and 4) signature of informed consent. The exclusion criteria are the following: 1) left bundle branch block, 2) acute cardiac necrosis in the absence of significant epicardial coronary artery stenosis, 3) STE ≤ 0.1 mV with pathologic Q wave, 4) severe anemia (hemoglobin <8.0 g/dl). For each patient without acute cardiac necrosis, the next patient from that center of the same sex and similar age (± 5 years) with myocardial infarction and acute coronary occlusion will be included. A manual centralized electrocardiographic analysis and another by deep learning AI will be performed.

CONCLUSIONS

The results of the study will provide new information for the stratification of patients with STE. Our hypothesis is that an AI analysis of the surface electrocardiogram allows a better distinction of patients with STE due to acute myocardial ischemia, from those with another etiology.

Likelihood of myocardial infarction, revascularization and death following catheterization laboratory activation in patients with vs. without both chest pain and ST elevation

BACKGROUND

Emergent cardiac catheterization laboratory activation (CCLA) for patients with suspected ST-elevation myocardial infarction (STEMI) is employed to expedite acute revascularization (AR). The incidence of false-positive CCLA, in which AR is not performed, remains high. The combination of chest pain (CP) and electrocardiographic ST elevation (STE) are the hallmarks of STEMI. However, CCLA is sometimes initiated for patients lacking this combination. The study objective was to quantify the difference in likelihood of AR and mortality in patients with vs. without both CP and STE.

METHODS

Retrospective analysis of 1621 consecutive patients for whom CCLA was initiated in a six-hospital network. We assessed the likelihood of acute myocardial infarction (AMI), presence of a culprit lesion (CL), performance of AR, and hospital mortality among patients with both CP and STE (+CP/+STE) compared with patients lacking one or both [non(CP/STE)].

RESULTS

87.0% of patients presented with CP, 82.4% with STE, and 73.7% with both. Among +CP/+STE patients, AMI was confirmed in 90.4%, a CL in 88.9%, and AR performed in 83.1%. The corresponding values among non(CP/STE) patients were 35.8, 31.9, and 28.1%, respectively (P < 0.0001 for each). Nevertheless, mortality among non(CP/STE) patients was three-fold higher than in +CP/+STE patients (13.3% vs. 4.5%; P < 0.0001), with non-coronary deaths 24-fold more likely.

CONCLUSION

Patients lacking the combination of CP and STE have a markedly lower likelihood of AMI and AR than +CP/+STE patients, but significantly higher mortality. Protocols aimed at rapid, focused evaluation of non(CP/STE) patients prior to CCLA are needed.

Sharing and Teaching Electrocardiograms to Minimize Infarction (STEMI): reducing diagnostic time for acute coronary occlusion in the emergency department

BACKGROUND

Limits to ST-Elevation Myocardial Infarction (STEMI) criteria may lead to prolonged diagnostic time for acute coronary occlusion. We aimed to reduce ECG-to-Activation (ETA) time through audit and feedback on STEMI-equivalents and subtle occlusions, without increasing Code STEMIs without culprit lesions.

METHODS

This multi-centre, quality improvement initiative reviewed all Code STEMI patients from the emergency department (ED) over a one-year baseline and one-year intervention period. We measured ETA time, from the first ED ECG to the time a Code STEMI was activated. Our intervention strategy involved a grand rounds presentation and an internal website presenting weekly local challenging cases, along with literature on STEMI-equivalents and subtle occlusions. Our outcome measure was ETA time for culprit lesions, our process measure was website views/visits, and our balancing measure was the percentage of Code STEMIs without culprit lesions.

RESULTS

There were 51 culprit lesions in the baseline period, and 64 in the intervention period. Median ETA declined from 28.0 min (95% confidence interval [CI] 15.0-45.0) to 8.0 min (95%CI 6.0-15.0). The website garnered 70.4 views/week and 27.7 visitors/week in a group of 80 physicians. There was no change in percentage of Code STEMIs without culprit lesions: 28.2% (95%CI 17.8-38.6) to 20.0% (95%CI 11.2-28.8%). Conclusions Our novel weekly web-based feedback to all emergency physicians was associated with a reduction in ETA time by 20 min, without increasing Code STEMIs without culprit lesions. Local ECG audit and feedback, guided by ETA as a quality metric for acute coronary occlusion, could be replicated in other settings to improve care.

[High-risk ECGs in acute chest pain : Signs of acute ischemia beyond STEMI]

BACKGROUND

Obtaining an electrocardiogram (ECG) is the gold standard for initial diagnostics of atraumatic chest pain. To provide optimal patient care, the treating physician has to be proficient in recognizing early signs of myocardial ischemia. Information from the clinical assessment and typical ECG signs have to be recognized promptly in order to diagnose myocardial ischemia early.

METHODS

A selective literature search in international databases (PubMed, Cochrane Library, Google Scholar) was conducted; current, topic-specific websites and literature were also included and evaluated.

RESULTS

Several subtle ECG abnormalities exist besides the typical ST-elevation myocardial infarction (STEMI) and well-known STEMI equivalents and may point to possible myocardial ischemia.

DISCUSSION

To fully evaluate the ECG in patients with atraumatic chest pain, typical signs of ischemia like STEMI as well as subtle ECG signs should be recognized to allow early cardiac intervention.

The rare presentation of the de Winter's pattern: Case report and literature review

Although not classified as a ST elevated myocardial infarction (STEMI), the patterns known as equivalents also require prompt recognition and treatment. A 50-year-old male with no pertinent history presented to the emergency department for chest pain that radiated to his left shoulder. An electrocardiogram (EKG) revealed findings consistent with the de Winter's pattern, which were greater than 1 mm upsloping ST depressions at the J point in leads V3-V6 (maximally in leads V3-V5), tall, peaked T waves in leads II, III, and V3-V5, ST elevations in lead aVR, and 1 mm ST elevation in V1 and V2. The physical exam, troponins, and other laboratory investigations were unrevealing. Urgent, diagnostic coronary angiography revealed complete occlusion of the proximal left anterior descending (LAD) artery, which was successfully treated with percutaneous coronary intervention (PCI) and two drug-eluting stents. After the stent placement, arterial blood flow was re-established and the ECG normalized. The patient was started on guideline based treatment and discharged home once medically stable. The de Winter's pattern on electrocardiogram indicates a significant coronary artery disease. This pattern requires urgent intervention, typically percutaneous stent placement.

The de Winter electrocardiogram pattern in a 52-year-old-male: a case report

BACKGROUND

The 12-lead electrocardiogram (ECG) remains the primary test for diagnosis of acute myocardial infarction (MI) secondary to acute coronary occlusion or near occlusion, with insufficient collateral circulation. Decisions regarding urgent reperfusion are based on whether or not there's new ST-segment elevation. The de Winter ECG pattern is a distinct ECG pattern without any ST-segment elevation, it may be missed by anyone unfamiliar with it.

CASE SUMMARY

We present a case whose chief complaint was severe central chest pain, the patient was diagnosed with acute MI secondary to a culprit lesion in the left anterior descending artery, despite the ECG not meeting standard STEMI criteria. After the ECG's significance was recognized by paramedics, the patient received immediate percutaneous coronary intervention with stenting and was discharged home after a brief hospital admission.

DISCUSSION

In some cases, acute MI presents with ECG features that do not meet the standard criteria for STEMI diagnosis. The de Winter ECG pattern is one such example. This pattern should be immediately recognizable to those responsible for the activation of the catheterization laboratory, physicians, and paramedics included.

Effect of Real-Time Physician Oversight of Prehospital STEMI Diagnosis on ECG-Inappropriate and False Positive Catheterization Laboratory Activation

Background

ST-elevation myocardial infarction diagnosis at first medical contact (FMC) and prehospital cardiac catheterization laboratory (CCL) activation are associated with reduced total ischemic time and therefore have become the dominant ST-elevation myocardial infarction referral method in primary percutaneous coronary intervention systems. We sought to determine whether physician oversight was associated with improved diagnostic performance in a prehospital CCL activation system and what effect the additional interpretation has on treatment delay.

Methods

Between 2012 and 2015, all patients in 2 greater Montreal catchment areas with a chief symptom of chest paint or dyspnea had an in-the-field electrocardiogram (ECG). A machine diagnosis of "acute myocardial infarction" resulted either in automatic CCL (automated cohort without oversight) or transmission of the ECG to the receiving centre emergency physician for reinterpretation before CCL activation. System performance was assessed in terms of the proportion of false positive and inappropriate activations (IA), as well as the proportion of patients with FMC-to-device times ≤ 90 minutes.

Results

Four hundred twenty-eight (428) activations were analyzed (311 automated; 117 with physician oversight). Physician oversight tended to decrease IAs (7% vs 3%; P = 0.062), but was also associated with a smaller proportion of patients achieving target FMC-to-device (76% vs 60%; P < 0.001). There was no significant effect on the proportion of false positive activation.

Conclusions

Real-time physician oversight might be associated with fewer IAs, but also appears to have a deleterious effect on FMC-to-device performance. Identifying predictors of IA could improve overall performance by selecting ECGs that merit physician oversight and streamlining others. Larger clinical studies are warranted.

Acute Myocardial Infarction Identified by Paramedics Using the Smith-Modified Sgarbossa Criteria: A Case Report

Identifying acute MI in the setting of left bundle branch block (LBBB) is challenging because ST-segment elevation is often found at baseline. When faced with LBBB and ischemic symptoms, identifying which patients require urgent reperfusion therapy is critical. Sgarbossa et al. derived three criteria that can be used to help identify these patients, Smith et al. refined these criteria creating the Smith-modified Sgarbossa criteria. We present a case of LBBB meeting the Smith-modified Sgarbossa criteria, recognized by paramedics and used to activate the catheterization laboratory after normal business hours. The patient was found with 95% stenosis of the left anterior descending artery and received stenting.

Diagnostic Performance and Pressure Stability of a Novel Myocardial Ischemic Diagnostic Index - The Intracoronary-Electrocardiogram-Triggered Distal Pressure/Aortic Pressure Ratio

Background: We hypothesized that the intracoronary-electrocardiogram (IC-ECG)-based pressure index would be more stable and precise than the instantaneous flow reserve (iFR). We investigated the usefulness of the IC-ECG-based pressure index for diagnosing myocardial ischemia. Methods and Results: Thirty-seven consecutive patients with coronary stenosis requiring physiological assessment were enrolled in the study. iFR was measured at rest and under hyperemia in 51 and 40 lesions, respectively. The IC-ECG-triggered distal pressure (Pd)/aortic pressure (Pa) ratio (ICE-T) was defined as the mean Pd/Pa ratio in the period corresponding to the isoelectric line. The ICE-T was significantly lower than the iFR both at rest and during hyperemia (P<0.00001 for both). Fluctuations in the ICE-T pressure parameters (Pd/Pa, Pa, and Pd) were significantly smaller than those of iFR both at rest and during hyperemia. The diagnostic accuracy of predicting a fractional flow reserve (FFR) ≤0.80 of the ICE-T at rest was significantly higher than that of iFR (P=0.008). Receiver operating characteristic curve analyses showed that the ICE-T predicts FFR ≤0.80 more accurately than the iFR (area under curve 0.897 vs. 0.810 for ICE-T and iFR, respectively). Conclusions: We identified the period in the IC-ECG in which resting Pd/Pa was low and constant. The IC-ECG-based algorithm may improve the accuracy of diagnosing myocardial ischemia, without increasing invasiveness, compared with pressure-dependent indices.

Early detection of ST-segment elevated myocardial infarction by artificial intelligence with 12-lead electrocardiogram

Patient delay is a worldwide unsolved problem in ST-segment elevated myocardial infarction (STEMI). An accurate warning system based on electrocardiogram (ECG) may be a solution for this problem, and artificial intelligence (AI) may offer a path to improve its accuracy and efficiency. In the present study, an AI-based STEMI autodiagnosis algorithm was developed using a dataset of 667 STEMI ECGs and 7571 control ECGs. The algorithm for detecting STEMI proposed in the present study achieved an area under the receiver operating curve (AUC) of 0.9954 (95% CI, 0.9885 to 1) with sensitivity (recall), specificity, accuracy, precision and F1 scores of 96.75%, 99.20%, 99.01%, 90.86% and 0.9372 respectively, in the external evaluation. In a comparative test with cardiologists, the algorithm had an AUC of 0.9740 (95% CI, 0.9419 to 1), and its sensitivity (recall), specificity, accuracy, precision, and F1 score were 90%, 98% and 94%, 97.82% and 0.9375 respectively, while the medical doctors had sensitivity (recall), specificity, accuracy, precision and F1 score of 71.73%, 89.33%, 80.53%, 87.05% and 0.8817 respectively. This study developed an AI-based, cardiologist-level algorithm for identifying STEMI.

[de Winter syndrome, an easily ignored but life-threatening disease: a case report]

de Winter syndrome is a special equivalent of anterior ST-segment elevation myocardial infarction (STEMI) characterized by the absence of overt ST-elevation with upsloping ST-segment depression followed by tall symmetrical T-waves in the precordial leads, often associated with total occlusion of the proximal left anterior descending coronary artery. Herein we present a case of de Winter syndrome in a 63-year-old man, whose initial ECG showed no ST-segment elevation, but subsequent coronary angiography confirmed total occlusion of the proximal LAD coronary artery. The patient was successfully treated via mechanical reperfusion therapy and stenting through percutaneous coronary intervention (PCI). de Winter syndrome is associated with a high mortality often due to insufficient awareness of this condition by clinicians. Immediate reperfusion therapy by PCI is the life-saving treatment for the patients diagnosed with this syndrome, and prompt recognition of the ECG pattern is critical to ensure the timely administration of the therapy.

A middle-aged male patient with de Winter syndrome: a case report

Background

De Winter syndrome accounts for approximately 2% of all patients with acute anterior myocardial infarction admitted to the emergency department, and is characterized by severe stenosis of the left anterior descending coronary artery (LAD). The ECG changes are not recognized by ECG software, and poor understanding of the syndrome among physicians may lead to misdiagnosis, delayed reperfusion, and mortality.

Case presentation

A 51-year-old male patient presented with a newly developed ECG pattern suggestive of de Winter Syndrome. Coronary angiography revealed anterior myocardial infarction. Based on the ECG and clinical manifestations, the patient was diagnosed with de Winter syndrome and underwent timely percutaneous coronary intervention to revascularize the left anterior descending artery (LAD). The patient showed good outcomes and no complications at 4 months after the operation.

Conclusions

This case highlights the importance of being aware of the possibility of de Winter syndrome in patients with symptoms of myocardial infarction but atypical ECG in order to conduct early revascularization and treatments.

Heat map visualization for electrocardiogram data analysis

BACKGROUND

Most electrocardiogram (ECG) studies still take advantage of traditional statistical functions, and the results are mostly presented in tables, histograms, and curves. Few papers display ECG data by visual means. The aim of this study was to analyze and show data for electrocardiographic left ventricular hypertrophy (LVH) with ST-segment elevation (STE) by a heat map in order to explore the feasibility and clinical value of heat mapping for ECG data visualization.

METHODS

We sequentially collected the electrocardiograms of inpatients in the First Affiliated Hospital of Shantou University Medical College from July 2015 to December 2015 in order to screen cases of LVH with STE. HemI 1.0 software was used to draw heat maps to display the STE of each lead of each collected ECG. Cluster analysis was carried out based on the heat map and the results were drawn as tree maps (pedigree maps) in the heat map.

RESULTS

In total, 60 cases of electrocardiographic LVH with STE were screened and analyzed. STE leads were mainly in the V₁, V₂ and V₃ leads. The ST-segment shifts of each lead of each collected ECG could be conveniently visualized in the heat map. According to cluster analysis in the heat map, STE leads were clustered into two categories, comprising of the right precordial leads (V₁, V₂, V₃) and others (V₄, V₅, V₆, I, II, III, aVF, aVL, aVR). Moreover, the STE amplitude in 40% (24 out of 60) of cases reached the threshold specified in the STEMI guideline. These cases also could be fully displayed and visualized in the heat map. Cluster analysis in the heat map showed that the III, aVF and aVR leads could be clustered together, the V₁, V₂, V₃ and V₄ leads could be clustered together, and the V₅, V₆, I and aVL leads could be clustered together.

CONCLUSION

Heat maps and cluster analysis can be used to fully display every lead of each electrocardiogram and provide relatively comprehensive information.

De Winter T-wave Electrocardiogram Pattern Due to Thromboembolic Event: A Rare Phenomenon

De winter pattern on the ECG is associated with occlusion of proximal left anterior descending artery. It is an atypical presentation of acute myocardial infarction due to LAD occlusion. We report a case due to thromboembolic occlusion of LAD after chemical cardioversion. It is imperative for cardiologists and physicians to instantly identify the De Winter pattern on ECG to appropriately triage these patients without delay.

Occluded or Not?

This report describes the case of a 48-year-old man whose electrocardiogram after cardiopulmonary resuscitation showed up-sloping ST-segment depression at the J point in precordial leads combined with tall symmetrical T waves. This electrocardiographic pattern corresponded to de Winter syndrome and is related to proximal left anterior descending coronary artery occlusion. (Level of Difficulty: Beginner.)

Cancellation of the Cardiac Catheterization Lab After Activation for ST-Segment-Elevation Myocardial Infarction

BACKGROUND

Prehospital ECG-based cardiac catheterization laboratory (CCL) activation for ST-segment-elevation myocardial infarction reduces door-to-balloon times, but CCL cancellations (CCL^X) remain a challenging problem. We examined the reasons for CCL^X, clinical characteristics, and outcomes of patients presenting as ST-segment-elevation myocardial infarction activations who receive emergent coronary angiography (EA) compared with CCL^X.

METHODS AND RESULTS

We reviewed all consecutive CCL activations between January 1, 2012, and December 31, 2014 (n=1332). Data were analyzed comparing 2 groups stratified as EA (n=466) versus CCL^X (n=866; 65%). Reasons for CCL^X included bundle branch block (21%), poor-quality prehospital ECG (18%), non-ST-segment-elevation myocardial infarction ST changes (18%), repolarization abnormality (13%), and arrhythmia (8%). A multivariate logistic regression model using age, peak troponin, and initial ECG findings had a high discriminatory value for determining EA versus CCL^X (C statistic, 0.985). CCL^X subjects were older and more likely to be women, have prior coronary artery bypass grafting, or a paced rhythm ( P<0.0001 for all). All-cause mortality did not differ between groups at 1 year or during the study period (mean follow-up, 2.186±1.167 years; 15.8% EA versus 16.2% CCL^X; P=0.9377). Cardiac death was higher in the EA group (11.8% versus 3.0%; P<0.0001). After adjusting for clinical variables associated with survival, CCL^X was associated with an increased risk for all-cause mortality during the study period (hazard ratio, 1.82; 95% CI, 1.28-2.59; P=0.0009).

CONCLUSIONS

In this study, prehospital ECG without overreading or transmission lead to frequent CCL^X. CCL^X subjects differ with regard to age, sex, risk factors, and comorbidities. However, CCL^X patients represent a high-risk population, with frequently positive cardiac enzymes and similar short- and long-term mortality compared with EA. Further studies are needed to determine how quality improvement initiatives can lower the rates of CCL^X and influence clinical outcomes.

Diagnosis of acute myocardial infarction in the presence of left bundle branch block

OBJECTIVE

Patients with suspected acute myocardial infarction (AMI) in the setting of left bundle branch block (LBBB) present an important diagnostic and therapeutic challenge to the clinician.

METHODS

We prospectively evaluated the incidence of AMI and diagnostic performance of specific ECG and high-sensitivity cardiac troponin (hs-cTn) criteria in patients presenting with chest discomfort to 26 emergency departments in three international, prospective, diagnostic studies. The final diagnosis of AMI was centrally adjudicated by two independent cardiologists according to the universal definition of myocardial infarction.

RESULTS

Among 8830 patients, LBBB was present in 247 (2.8%). AMI was the final diagnosis in 30% of patients with LBBB, with similar incidence in those with known LBBB versus those with presumably new LBBB (29% vs 35%, p=0.42). ECG criteria had low sensitivity (1%-12%) but high specificity (95%-100%) for AMI. The diagnostic accuracy as quantified by the receiver operating characteristics (ROC) curve of hs-cTnT and hs-cTnI concentrations at presentation (area under the ROC curve (AUC) 0.91, 95% CI 0.85 to 0.96 and AUC 0.89, 95% CI 0.83 to 0.95), as well as that of their 0/1-hour and 0/2-hour changes, was very high. A diagnostic algorithm combining ECG criteria with hs-cTnT/I concentrations and their absolute changes at 1 hour or 2 hours derived in cohort 1 (45 of 45(100%) patients with AMI correctly identified) showed high efficacy and accuracy when externally validated in cohorts 2 and 3 (28 of 29 patients, 97%).

CONCLUSION

Most patients presenting with suspected AMI and LBBB will be found to have diagnoses other than AMI. Combining ECG criteria with hs-cTnT/I testing at 0/1 hour or 0/2 hours allows early and accurate diagnosis of AMI in LBBB.

TRIAL REGISTRATION NUMBER

APACE: NCT00470587; ADAPT: ACTRN12611001069943; TRAPID-AMI: RD001107;Results.

Renal Failure Impact on the Outcomes of ST-Segment Elevation Myocardial Infarction Patients Due to a Left Main Coronary Culprit Lesion Treated Using a Primary Percutaneous Coronary Intervention

BACKGROUND

Patients with ST-segment elevation myocardial infarction (STEMI) and primary percutaneous coronary intervention (PPCI) on a left main culprit lesion have very high mortality rates. The interaction of chronic kidney disease (CKD) with such a catastrophic acute event on the background of their highly complex atherosclerotic lesions is not well established. Therefore, we sought to evaluate in these patients the influence of the estimated glomerular filtration rate (eGFR) on short- and long-term mortality.

METHODS

We retrospectively analyzed renal function in 81 patients with STEMI and PPCI on a left main culprit lesion from two tertiary centers.

RESULTS

Patients were divided in two groups according to an eGFR cut-off of 60 mL/min/1.73 m2: 40 patients with CKD and 41 without CKD. Patients with renal failure were older, had more diabetes, and had experienced more frequent myocardial infarction MIs. CKD patients had a higher baseline-SYNTAX score (p = 0.015), higher residual-SYNTAX score (p < 0.001), and lower SYNTAX revascularization index-SRI (p = 0.003). Mortality at 30-day, 1-year, and 3-year follow-ups were not significantly different between the two groups. However, when analyzed as a continuous variable, eGFR emerged as a predictor of 1-year mortality, both in univariate analysis (OR = 0.97, 95% CI: 0.95-0.99, p = 0.005) and in multivariate analysis, after adjusting for cardiogenic shock and Thrombolysis in Myocardial Infarction TIMI 0/1 flow (OR = 0.975, 95% CI: 0.95-0.99, p = 0.021).

CONCLUSIONS

In STEMI with PPCI on a left main culprit lesion, renal failure was associated with more complex coronary lesions and less complete revascularization, and turned out to be an independent predictor of mortality at 1-year follow-up.

False activation of the cardiac catheterization laboratory: The price to pay for shorter treatment delay

Introduction

In patients with acute ST elevation myocardial ischemia (STEMI), national efforts have focused on reducing door-to-balloon (D2B) times for primary percutaneous coronary intervention (PCI). This emphasis on time-to-treatment may increase the rate of inappropriate cardiac catheterization laboratory (CCL) activations and unnecessary healthcare utilization. To achieve lower D2B times, community hospitals and EMS systems have enabled emergency medical technicians (EMTs) and emergency department (ED) physicians to activate the CCLs without immediately consulting a cardiologist.

Objective

The purpose of this study is to determine the rate and main causes of inappropriate activation of the CCL which will aid in finding solutions to reduce this occurrence.

Method

This is a retrospective study, based on an electronic medical system review of all inappropriate CCL activation who presented to Providence Hospital and Medical Centers (PHMC) in Michigan, from January 2015 to July 2016.

Results

The CCL was activated 375 times for suspected STEMI. The false STEMI activation was identified in 47 patients which represents 12.5% of total CCL activation. The vast majority of this false activation was due to non-diagnostic electrocardiogram (ECG) that did not meet the STEMI criteria.

Conclusion

The subjective interpretation of the ECG by EMTs and ED physicians tend to show a wide variability, which may lead to higher-than-anticipated false activation rates of up to 36% in one study. Some studies had reported that up to 72% of inappropriate activations were caused by ECG misinterpretations. These false activations have ramifications that lead to both clinical and financial costs.

Evaluation of acute anterior myocardial infarction cases with de-Winter T waves by coronary angiography images

INTRODUCTION

Acute myocardial infarction (AMI) is the leading cause of mortality worldwide and with immediate invasive strategy, the extent of myocardial injury can be reduced. In recent studies, de-Winter T waves were defined as a sign of proximal left anterior descending artery (LAD) occlusion. In this electrocardiography (ECG) pattern, no ST elevation is seen, but an upsloping ST segment depression (>1mm) beginning from J-point, and symmetrical, long and significant T waves are seen in precordial leads.

CASE REPORTS

We present three patients who were admitted to emergency department with symptoms of chest pain. Their ECGs revealed de-Winter T waves, therefore, coronary angiography was performed. Total LAD occlusion was observed in all patients, and stents were implanted to the culprit lesion.

CONCLUSION

We aim to emphasize the importance of de-Winter T waves since physicians should recognize this ECG pattern immediately in emergency situations to provide appropriate treatment to STEMI patients.

New Predictors of Early and Late Outcomes after Primary Percutaneous Coronary Intervention in Patients with ST-Segment Elevation Myocardial Infarction and Unprotected Left Main Coronary Artery Culprit Lesion

Objectives

The study evaluated the correlation between baseline SYNTAX Score, Residual SYNTAX Score, and SYNTAX Revascularization Index and long-term outcomes in ST-elevation myocardial infarction (STEMI) patients with primary percutaneous coronary intervention (PCI) on an unprotected left main coronary artery lesion (UPLMCA).

Background

Previous studies on primary PCI in UPLMCA have identified cardiogenic shock, TIMI 0/1 flow, and cardiac arrest, as prognostic factors of an unfavourable outcome, but the complexity of coronary artery disease and the extent of revascularization have not been thoroughly investigated in these high-risk patients.

Methods

30-day, 1-year, and long-term outcomes were analyzed in a cohort of retrospectively selected, 81 consecutive patients with STEMI, and primary PCI on UPLMCA.

Results

Cardiogenic shock (p=0.001), age (p=0.008), baseline SYNTAX Score II (p=0.006), and SYNTAX Revascularization Index (p=0.046) were independent mortality predictors at one-year follow-up. Besides cardiogenic shock (HR 3.28, p<0.001), TIMI 0/1 flow (HR 2.17, p=0.021) and age (HR 1.03, p=0.006), baseline SYNTAX Score II (HR 1.06, p=0.006), residual SYNTAX Score (HR 1.03, p=0.041), and SYNTAX Revascularization Index (HR 0.9, p=0.011) were independent predictors of mortality at three years of follow-up. In patients with TIMI 0/1 flow, the presence of Rentrop collaterals was an independent predictor for long-term survival (HR 0.24; p=0.049).

Conclusions

In this study, the complexity of coronary artery disease and the extent of revascularization represent independent mortality predictors at long-term follow-up.

Improving Electrocardiography Diagnostic Accuracy in Emergency Medical Services Personnel

Background

Accuracy of electrocardiogram (ECG) interpretation is important for identification of ST-elevation myocardial infarction (STEMI) by Emergency Medical Services (EMS) personnel who recognize STEMI in the field and activate the coronary catheterization laboratory. According to previous research, there is improvement in diagnosis of STEMIs for healthcare providers who read an average of > 20 ECGs per week. This study evaluated the effectiveness of online ECG modules on improving diagnostic accuracy.

Methods

EMS personnel received 25 ECGs per week to interpret via an online program. Diagnostic accuracy was assessed for improvement via completion of an ECG evaluation package before and after the intervention. Job satisfaction data were collected to determine the impact of the educational initiative.

Results

A total of 64 participants completed the study. Overall, there was an improvement in ECG diagnostic accuracy from 50.8% to 61.2% (95% confidence interval [CI], 7.7-13.2; P < 0.0001). Specifically, there was significant improvement in the diagnosis of STEMI (8.5%; 95% CI, 4.9-12.3; P < 0.003) and supraventricular tachycardia (39.0%; 95% CI, 17.2-60.8; P < 0.008), with a trend toward improvement in all other diagnoses. These effects were sustained to 3 months (9.6%; 95% CI, 6.4-12.7; P < 0.0001). Improvement was seen regardless of employment experience and training. There was no significant impact on job satisfaction.

Conclusions

ECG exposure remains an important factor in improving the accuracy of ECG diagnosis in EMS personnel. Online education modules provide an easily accessible way of improving ECG interpretation with the opportunity for positive downstream effects on patient outcomes and resource use.

Should de Winter T-Wave Electrocardiography Pattern Be Treated as ST-Segment Elevation Myocardial Infarction Equivalent with Consequent Reperfusion? A Dilemmatic Experience in Rural Area of Indonesia

Background

Although de Winter T-wave electrocardiography pattern is rare, it signifies proximal left anterior descending artery occlusion and is often unrecognized by physicians. The aim of this case report was to highlight the dilemma in the management of a patient with de Winter T-wave pattern in the hospital without interventional cardiology facility.

Case Presentation

A 65-year-old male presented with typical chest pain since 2 hours before admission, and ECG showed sinus rhythm of 57 bpm and >1 mm upsloping ST depression with symmetric tall T in lead V_2-3 characteristic of de Winter T-wave ECG pattern. He was given dual antiplatelet therapy, nitrate, statin, and anticoagulant. He refused referral to interventional cardiology available hospital. 3 hours after admission, the electrocardiography transformed into Q-waves consistent with final stages of acute STEMI and ST-segment elevation that barely meets the threshold in the guideline, and thrombolytic was administered and successful. There is a suggestion that de Winter T-wave electrocardiography should be treated as ST-segment myocardial infarction equivalent and should undergo coronary angiography; however, not every hospital has the luxury of interventional cardiology facility. The other modality for reperfusion is thrombolysis; however, without a clear guideline and scarcity of study, we prefer to resort to conservative treatment. “Fortunately,” transformation into ST-segment elevation helps us to determine the course of action which is reperfusion using thrombolytic.

Conclusions

de Winter T-wave ECG pattern is not mentioned in any guidelines regarding acute coronary syndromes, and there are no clear recommendations. Physicians in rural area without interventional cardiology facility face a dilemma with the lack of evidence-based guideline. Fibrinolytic may be appropriate in those without contraindications with strong chest pain consistent with acute coronary occlusion, less than 3 hours of symptoms, and convincing de Winter T-wave ECG pattern for a rural non-PCI hospital far away from PCI capable hospital.

New Insights Into the Use of the 12-Lead Electrocardiogram for Diagnosing Acute Myocardial Infarction in the Emergency Department

The 12-lead electrocardiogram (ECG) remains the most immediately accessible and widely used initial diagnostic tool for guiding management in patients with suspected myocardial infarction (MI). Although the development of high-sensitivity cardiac troponin assays has improved the rule-in and rule-out and risk stratification of acute MI without ST elevation, the immediate management of the subset of acute MI with acute coronary occlusion depends on integrating clinical presentation and ECG findings. Careful interpretation of the ECG might yield subtle features suggestive of ischemia that might facilitate more rapid triage of patients with subtle acute coronary occlusion or, conversely, in identification of ST-elevation MI mimics (pseudo ST-elevation MI patterns). Our goal in this review article is to consider recent advances in the use of the ECG to diagnose coronary occlusion MIs, including the application of rules that allow MI to be diagnosed on the basis of atypical ECG manifestations. Such rules include the modified Sgarbossa criteria allowing identification of acute MI in left bundle branch block or ventricular pacing, the 3- and 4-variable formula to differentiate normal ST elevation (formerly called early repolarization) from subtle ECG signs of left anterior descending coronary artery occlusion, the differentiation of ST elevation of left ventricular aneurysm from that of acute anterior MI, and the use of lead aVL in the recognition of inferior MI. Improved use of the ECG is essential to improving the diagnosis and appropriate early management of acute coronary occlusion MIs, which will lead to improved outcomes for patients who present with acute coronary syndrome.

A Novel Electrocardiographic Sign of an ST-Segment Elevation Myocardial Infarction-Equivalent: De Winter Syndrome

Patients with de Winter syndrome, also termed anterior ST-segment elevation myocardial infarction (STEMI)-equivalent, represent 2% of all patients with acute anterior myocardial infarctions admitted to emergency departments (EDs). STEMI-equivalents do not present with classical electrocardiogram (ECG) changes but exhibit a critical stenosis of the left anterior descending (LAD) coronary artery. This is under-recognized by clinicians and is therefore associated with high morbidity and mortality. Here, we report a rare case of a novel, typical, STEMI-equivalent ECG pattern without obvious ST-segment elevation in a 34-year-old female who presented to our ED with substantial chest pain and a large, acute, transmural anterior myocardial infarction caused by acute occlusion of the LAD coronary artery. However, she presented as a non-STEMI case. A definite diagnosis of de Winter syndrome was made on the basis of clinical and ECG findings.

False Activations for ST-Segment Elevation Myocardial Infarction

First-medical-contact-to-device (FMC2D) times have improved over the past decade, as have clinical outcomes for patients presenting with ST-elevation myocardial infarction (STEMI). However, with improvements in FMC2D times, false activation of the cardiac catheterization laboratory (CCL) has become a challenging problem. The authors define false activation as any patient who does not warrant emergent coronary angiography for STEMI. In addition to clinical outcome measures for these patients, STEMI systems should collect data regarding the total number of CCL activations, the total number of emergency coronary angiograms, and the number revascularization procedures performed.

Effectiveness of a Prehospital Wireless 12-Lead Electrocardiogram and Cardiac Catheterization Laboratory Activation for ST-Elevation Myocardial Infarction

The aim of the study was to determine the prevalence of false-positive and inappropriate cardiac catheterization laboratory (CCL) activation in patients suspected with ST-elevation myocardial infarction (STEMI) diverted to a percutaneous coronary intervention (PCI) facility after paramedics wireless 12-lead electrocardiogram transmission to an emergency physician at an online medical control center. This retrospective study collected data from medical records of patients with suspected STEMI from 2006 to 2014. It included demographics, coronaropathic risk factors, cardiac biomarkers, time from the first medical contact to treatment, and final diagnosis. Primary outcome was the rate of false-positive and inappropriate CCL activation. As secondary outcomes, we compared patient characteristics between cases of appropriate and inappropriate CCL activation, and we assessed the presence of cardiac biomarkers, time from first medical contact to start of PCI, and final diagnosis. Overall, 673 patients with suspected STEMI were included in the analysis. A total of 640 patients (95%) had coronarography, of which 10% (62 of 640) did not have a culprit coronary artery (false positive). Angiography was canceled for 5% (33 of 673) of patients. The total false-positive and inappropriate CCL activation rate was 14% (95 of 673). Average time from the first medical contact to the start of PCI was 47 ± 18.1 minutes. Unwanted CCL activations were more likely to involve men aged >65 years and patients with a history of coronary artery disease. In conclusion, our system of transmitted prehospital electrocardiography and STEMI interpretation by emergency physicians at an online medical control center showed a total false-positive and inappropriate CCL activation rate of 14% over the 8-year study period.