Incidence, angiographic features and outcomes of patients presenting with subtle ST-elevation myocardial infarction

ECG manifestations of occlusion of septal perforator of left anterior descending artery

The fourth universal definition of MI defines requires presence of j point elevation in two contiguous leads except v2-3 where the elevation should be equal to or >2 mm in men (2.5 mm in <40 years) and 1.5 mm in women.(1) We present two cases of patients who presented with electrocardiographic manifestations of occlusion of septal perforator of left anterior descending artery and discuss the salient feature of ECG in such patients. We also present the limitations of STEMI criteria given the dynamic nature of acute coronary occlusion and stress on early recognition of this MI.

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.

A clinical trial comparing complete revascularization at the time of primary percutaneous coronary intervention versus during the index hospital admission in patients with multi-vessel coronary artery disease and STEMI uncomplicated by cardiogenic shock

OBJECTIVE

In this study, we aimed to compare major adverse cardiac and cerebrovascular events (MACCE), defined as a composite of death, stroke, myocardial infarction and symptom-induced revascularization, and mortality within one year of randomization between two strategies; complete revascularization including non-culprit lesions percutaneous coronary intervention (PCI) during primary PCI (PPCI) versus complete revascularization during the same hospital admission in patients with multi-vascular coronary artery disease (MVD) presenting with ST-elevation myocardial infarction (STEMI) uncomplicated by cardiogenic shock.

METHODS

We randomized in a 1: 1 manner 100 patients with MVD and STEMI uncomplicated by cardiogenic shock who had undergone successful culprit-lesion PCI to either a strategy of complete revascularization with PCI of angiographically significant non-culprit lesions in the index PPCI procedure or to a strategy of complete revascularization during a second procedure that took place during the same hospital admission.

RESULTS

The first primary outcome was death within a timeframe of one year and the second a composite of MACCE within a year following complete revascularization. Of the total number of patients monitored, 4% in each of the two groups was associated with the first primary outcome (p=0.984) and the second primary outcome in 6% (p=0.970). There was no statistical difference between outcomes in the two groups.

CONCLUSION

Among patients with MVD and STEMI uncomplicated by cardiogenic shock, there was no difference regarding outcomes when using a strategy of complete revascularization of non-culprit lesions during PPCI or the same hospital admission.

Electrocardiographic Diagnosis of Acute Coronary Occlusion Myocardial Infarction in Ventricular Paced Rhythm Using the Modified Sgarbossa Criteria

STUDY OBJECTIVE

Ventricular paced rhythm is thought to obscure the electrocardiographic diagnosis of acute coronary occlusion myocardial infarction. Our primary aim was to compare the sensitivity of the modified Sgarbossa criteria (MSC) to that of the original Sgarbossa criteria for the diagnosis of occlusion myocardial infarction in patients with ventricular paced rhythm.

METHODS

In this retrospective case-control investigation, we studied adult patients with ventricular paced rhythm and symptoms of acute coronary syndrome who presented in an emergency manner to 16 international cardiac referral centers between January 2008 and January 2018. The occlusion myocardial infarction group was defined angiographically as thrombolysis in myocardial infarction grade 0 to 1 flow or angiographic evidence of coronary thrombosis and peak cardiac troponin I ≥10.0 ng/mL or troponin T ≥1.0 ng/mL. There were 2 control groups: the "non-occlusion myocardial infarction-angio" group consisted of patients who underwent coronary angiography for presumed type I myocardial infarction but did not meet the definition of occlusion myocardial infarction; the "no occlusion myocardial infarction" control group consisted of randomly selected emergency department patients without occlusion myocardial infarction.

RESULTS

There were 59 occlusion myocardial infarction, 90 non-occlusion myocardial infarction-angio, and 102 no occlusion myocardial infarction subjects (mean age, 72.0 years; 168 [66.9%] men). For the diagnosis of occlusion myocardial infarction, the MSC were more sensitive than the original Sgarbossa criteria (sensitivity 81% [95% confidence interval [CI] 69 to 90] versus 56% [95% CI 42 to 69]). Adding concordant ST-depression in V4 to V6 to the MSC yielded 86% (95% CI 75 to 94) sensitivity. For the no occlusion myocardial infarction control group of ED patients, additional test characteristics of MSC and original Sgarbossa criteria, respectively, were as follows: specificity 96% (95% CI 90 to 99) versus 97% (95% CI 92 to 99); negative likelihood ratio (LR) 0.19 (95% CI 0.11 to 0.33) versus 0.45 (95% CI 0.34 to 0.65); and positive LR 21 (95% CI 7.9 to 55) versus 19 (95% CI 6.1 to 59). For the non-occlusion myocardial infarction-angio control group, additional test characteristics of MSC and original Sgarbossa criteria, respectively, were as follows: specificity 84% (95% CI 76 to 91) versus 90% (95% CI 82 to 95); negative LR 0.22 (95% CI 0.13 to 0.38) versus 0.49 (95% CI 0.35 to 0.66); and positive LR 5.2 (95% CI 3.2 to 8.6) versus 5.6 (95% CI 2.9 to 11).

CONCLUSION

For the diagnosis of occlusion myocardial infarction in the presence of ventricular paced rhythm, the MSC were more sensitive than the original Sgarbossa criteria; specificity was high for both rules. The MSC may contribute to clinical decisionmaking for patients with ventricular paced rhythm.

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.

Time for a new paradigm shift in myocardial infarction

The ST-elevation myocardial infarction (STEMI)/non-STEMI paradigm per the current guidelines has important limitations. It misses a substantial proportion of acute coronary occlusions (ACO) and results in a significant amount of unnecessary catheterization laboratory activations. It is not widely appreciated how poor is the evidence base for the STEMI criteria; the recommended STEMI cutoffs were not derived by comparing those with ACO with those without and not specifically designed for distinguishing patients who would benefit from emergency reperfusion. This review aimed to discuss the origins, evidence base, and limitations of STEMI/non-STEMI paradigm and to call for a new paradigm shift to the occlusion MI (OMI)/non-OMI.

STEMI: A transitional fossil in MI classification?

An important task in emergency cardiology is distinguishing patients with acute coronary occlusion (ACO), who will benefit from emergent reperfusion therapy, from those without ongoing myocyte loss who can be managed with medical therapy and for whom potentially harmful invasive interventions can be deferred. The electrocardiogram is critical in this process. Although the ST-segment elevation myocardial infarction (STEMI)/non-STEMI paradigm is well-established, with "STEMI" representing ACO, its evidence base is poor, and this can have dire consequences. The universally recommended STEMI criteria do not accurately diagnose ACO; in fact, they miss more than one-fourth of the patients with ACO, and also result in a substantial burden of unnecessary catheterization laboratory activations. We here discuss why we believe it is time to change the current STEMI/non-STEMI paradigm.

DIagnostic accuracy oF electrocardiogram for acute coronary OCClUsion resuLTing in myocardial infarction (DIFOCCULT Study)

Background

Although ST-segment elevation (STE) has been used synonymously with acute coronary occlusion (ACO), current STE criteria miss nearly one-third of ACO and result in a substantial amount of false catheterization laboratory activations. As many other electrocardiographic (ECG) findings can reliably indicate ACO, we sought whether a new ACO/non-ACO myocardial infarction (MI) paradigm would result in better identification of the patients who need acute reperfusion therapy.

Methods

A total of 3000 patients were enrolled in STEMI, non-STEMI and control groups. All ECGs were reviewed by two cardiologists, blinded to any outcomes, for the current STEMI criteria and other subtle signs. A combined ACO endpoint was composed of peak troponin level, troponin rise within the first 24 h and angiographic appearance. The dead or alive status was checked from hospital records and from the electronic national database.

Results

In non-STEMI group, 28.2% of the patients were re-classified by the ECG reviewers as having ACO. This subgroup had a higher frequency of ACO, myocardial damage, and both in-hospital and long-term mortality compared to non-STEMI group. A prospective ACOMI/non-ACOMI approach to the ECG had superior diagnostic accuracy compared to the STE/non-STEMI approach in the prediction of ACO and long-term mortality. In Cox-regression analysis early intervention in patients with non-ACO-predicting ECGs was associated with a higher long-term mortality.

Conclusions

We believe that it is time for a new paradigm shift from the STEMI/non-STEMI to the ACOMI/non-ACOMI in the acute management of MI. (DIFOCCULT study; ClinicalTrials.gov number, NCT04022668.).

Body Surface Potential Mapping and Left Circumflex Occlusion: Unmasking the Hidden Acute Myocardial Infarction

See Article by Daly et al

A Simplified Formula Discriminating Subtle Anterior Wall Myocardial Infarction from Normal Variant ST-Segment Elevation

Benign variant (BV) ST-segment elevation (STE) is present in anterior chest leads in most individuals and may cause diagnostic confusion in patients presenting with chest pain. Recently, 2 regression formulas were proposed for differentiation of BV-STE from anterior ST-elevation myocardial infarction (MI) on the electrocardiogram, computation of which is heavily device-dependent. We hypothesized that a simpler visual-assessment-based formula, namely (R-wave amplitude in lead V4 + QRS amplitude in V2) - (QT interval in millimeters + STE60 in V3), will be noninferior to these formulas. Consecutive cases of proven left anterior descending occlusion were reviewed, and those with obvious ST elevation MI were excluded. First 200 consecutive patients with noncardiac chest pain and BV-STE were also enrolled as a control group. Relevant electrocardiographic parameters were measured. There were 138 anterior MI and 196 BV-STE cases. Our simple formula was superior to the 3- and noninferior to the 4-variable formulas. This new practical formula had an excellent area-under curve of 0.963 (95% confidence interval, 0.946 to 0.980, p<0.001). It also had a sensitivity, specificity and diagnostic accuracy of 86.9%, 92.3%, and 90.1%, respectively. In conclusion, a simple visual assessment-based formula can reliably differentiate STE MI from BV-STE. Also, our results emphasize that focusing only on STE for diagnosing acute coronary occlusion is extremely insensitive and even puts the term "STEMI" itself into question.

A tale of two formulas: Differentiation of subtle anterior MI from benign ST segment elevation

BACKGROUND

It may sometimes be difficult to differentiate subtle ST-segment elevation (STE) due to anterior myocardial infarction (MI) from benign variant (BV) STE. Recently, two related formulas were proposed for this purpose. However, they have never been tested in an external population.

MATERIALS AND METHODS

Consecutive patients from May 2017 to January 2018, who were admitted with the diagnosis of acute anterior STEMI, were enrolled. Electrocardiograms were systematically reviewed and only subtle ones were included. First 200 consecutive patients with noncardiac chest pain were also enrolled as a control group. Relevant electrocardiographic parameters were measured.

RESULTS

A total of 379 anterior MI and 200 BV-STE cases were enrolled during study period. A total of 241 patients in STEMI group were excluded for not matching subtleness criteria, four patients in control group were also excluded because of prior left-anterior descending artery intervention. The three-variable formula, with recommended cut-point of 23.5, had a sensitivity, specificity, and diagnostic accuracy of 73.9%, 86.7%, and 81.4%, respectively. The four-variable formula, with the published cut-point of 18.2, had a sensitivity, specificity, and diagnostic accuracy of 83.3%, 87.7%, and 85.9%, respectively.

CONCLUSION

Three- and four-variable formulas with recommended cutoffs have a reasonable sensitivity, specificity, and diagnostic accuracy in differentiating subtle STEMI with BV-STE. Although both perform well, the four-variable formula has a higher sensitivity, specificity, and diagnostic accuracy and should be preferred.

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 new 4-variable formula to differentiate normal variant ST segment elevation in V2-V4 (early repolarization) from subtle left anterior descending coronary occlusion - Adding QRS amplitude of V2 improves the model

INTRODUCTION

Precordial normal variant ST elevation (NV-STE), previously often called "early repolarization," may be difficult to differentiate from subtle ischemic STE due to left anterior descending (LAD) occlusion. We previously derived and validated a logistic regression formula that was far superior to STE alone for differentiating the two entities on the ECG. The tool uses R-wave amplitude in lead V4 (RAV4), ST elevation at 60 ms after the J-point in lead V3 (STE60V3) and the computerized Bazett-corrected QT interval (QTc-B). The 3-variable formula is: 1.196 x STE60V3 + 0.059 × QTc-B - 0.326 × RAV4 with a value ≥23.4 likely to be acute myocardial infarction (AMI).

HYPOTHESIS

Adding QRS voltage in V2 (QRSV2) would improve the accuracy of the formula.

METHODS

355 consecutive cases of proven LAD occlusion were reviewed, and those that were obvious ST elevation myocardial infarction were excluded. Exclusion was based on one straight or convex ST segment in V2-V6, 1 millimeter of summed inferior ST depression, any anterior ST depression, Q-waves, "terminal QRS distortion," or any ST elevation >5 mm. The NV-STE group comprised emergency department patients with chest pain who ruled out for AMI by serial troponins, had a cardiologist ECG read of "NV-STE," and had at least 1 mm of STE in V2 and V3. R-wave amplitude in lead V4 (RAV4), ST elevation at 60 ms after the J-point in lead V3 (STE60V3) and the computerized Bazett-corrected QT interval (QTc-B) had previously been measured in all ECGs; physicians blinded to outcome then measured QRSV2 in all ECGs. A 4-variable formula was derived to more accurately classify LAD occlusion vs. NV-STE and optimize area under the curve (AUC) and compared with the previous 3-variable formula.

RESULTS

There were 143 subtle LAD occlusions and 171 NV-STE. A low QRSV2 added diagnostic utility. The derived 4-variable formula is: 0.052*QTc-B - 0.151*QRSV2 - 0.268*RV4 + 1.062*STE60V3. The 3-variable formula had an AUC of 0.9538 vs. 0.9686 for the 4-variable formula (p = 0.0092). At the same specificity as the 3-variable formula [90.6%, at which cutpoint (≥23.4), 123 of 143 MI were correctly classified for 86% sensitivity], the sensitivity of the new formula at cutpoint ≥17.75 is 90.2%, with 129/143 correctly classified MI, identifying an additional 6 cases. The cutpoint with the highest accuracy (92.0%) was at a cutoff value ≥18.2, with 88.8% sensitivity, 94.7% specificity, and a positive and negative likelihood ratio of 16.9 (95% CI: 8.9-32) and 0.12 (95% CI: 0.07-0.19). At this cutpoint, it correctly classified an additional 11 cases (289 of 315, vs. 278 of 315): 127/143 for MI (an additional 4 cases) and 162/171 for NV-STE (an additional 7 cases).

CONCLUSION

On the ECG, a 4-variable formula was derived which adds QRSV2; it differentiates subtle LAD occlusion from NV-STE better than the 3-variable formula. At a value ≥18.2, the formula (0.052*QTc-B - 0.151*QRSV2 - 0.268*RV4 + 1.062*STE60V3) was very accurate, sensitive, and specific, with excellent positive and negative likelihood ratios. This formula needs to be validated.

Validation of the modified Sgarbossa criteria for acute coronary occlusion in the setting of left bundle branch block: A retrospective case-control study

BACKGROUND

The modified Sgarbossa criteria were proposed in a derivation study to be superior to the original criteria for diagnosing acute coronary occlusion (ACO) in left bundle branch block (LBBB). The new rule replaces the third criterion (5 mm of excessively discordant ST elevation [STE]) with a proportion (at least 1 mm STE and STE/S wave ≤-0.25). We sought to validate the modified criteria.

METHODS

This retrospective case-control study was performed by chart review in 2 tertiary care center emergency departments (EDs) and 1 regional referral center. A billing database was used at 1 site to identify all ED patients with LBBB and ischemic symptoms between May 2009 and June 2012. In addition, all 3 sites identified LBBB ACO patients who underwent emergent catheterization. We measured QRS amplitude and J-point deviation in all leads, blinded to outcomes. Acute coronary occlusion was determined by angiographic findings and cardiac biomarker levels, which were collected blinded to electrocardiograms. Diagnostic statistics of each rule were calculated and compared using McNemar's test.

RESULTS

Our consecutive cohort search identified 258 patients: 9 had ACO, and 249 were controls. Among the 3 sites, an additional 36 cases of ACO were identified, for a total of 45 ACO cases and 249 controls. The modified criteria were significantly more sensitive than the original weighted criteria (80% vs 49%, P < .001) and unweighted criteria (80% vs 56%, P < .001). Specificity of the modified criteria was not statistically different from the original weighted criteria (99% vs 100%, P = .5) but was significantly greater than the original unweighted criteria (99% vs 94%, P = .004).

CONCLUSIONS

The modified Sgarbossa criteria were superior to the original criteria for identifying ACO in LBBB.