Electrocardiogram patterns in acute left main coronary artery occlusion

Navigating Electrocardiographic Risk Stratification and Therapeutic Strategies in Acute Coronary Syndrome Without ST-Segment Elevation

Of the patients suffering acute proximal left anterior descending (LAD) artery occlusion, a small but not insignificant minority does not manifest the classical ST-segment elevation myocardial infarction (STEMI) electrocardiographic (ECG) patterns. They manifest junctional upsloping ST-segment depression followed by tall, symmetrical T waves in the precordial leads instead, known as the de Winter pattern. Such patients may suffer a nearly transmural infarct if not managed promptly with percutaneous coronary intervention (PCI). Therefore, they should be treated as suffering a STEMI equivalent. The patient presented here suffered a total proximal "wrap-around" LAD artery in-stent occlusion manifesting the de Winter ECG pattern. The latter, was correctly and promptly recognized and the patient was managed successfully with emergency PCI achieving a good outcome. Discussion pertains to the morphology of ST-segment depression (STD) and the polarity and magnitude of the T waves accompanying STD which provide prognostic information and facilitate risk stratification in patients presenting with non-ST-segment elevation acute coronary syndrome. The pathophysiology underlying the de Winter ECG pattern and the appropriate therapeutic strategy are also discussed. The Littmann concept is also discussed, providing a reliable explanation for the ST-segment elevation observed in a misplaced lead V1.

Severe hypokalemia mimicking classical electrocardiographic pattern of left Main coronary artery disease: A case report and a focused review of the literature

Several electrocardiographic alterations due to hypokalemia have been described, but the electrocardiographic presentation meeting criteria for occlusion of the left main coronary artery is very rare. We describe a case of hypokalemia simulating it.

Acute pulmonary embolism with electrocardiogram showing subtotal left main coronary artery occlusion: A case report

When the electrocardiogram of acute pulmonary embolism is similar to that of acute myocardial infarction, it is difficult to distinguish between the two diseases quickly and effectively. We present the case of a 50-year-old man with acute pulmonary embolism. His electrocardiogram showed subtotal occlusion of the left main coronary artery with ST segment depression in I, II, aVF, V3 to V6, ST segment elevation in aVR, V1 and S1Q3T3. Invasive coronary angiography did not show coronary artery stenosis, then pulmonary angiography was performed quickly which showed massive bilateral acute pulmonary embolism. Electrocardiogram cannot effectively distinguish acute pulmonary embolism from subtotal occlusion of the left main coronary artery. For patients with hemodynamic instability, if ultrasound cannot be performed in time, the combination of invasive coronary angiography and pulmonary angiography can be an option to distinguish acute pulmonary embolism from subtotal occlusion of the left main coronary artery and to treat.

Acute coronary syndrome with single‑lead ST segment elevation: A rare presentation of multivessel coronary artery disease

We report the case of a 73-year-old male admitted for epigastric pain and syncope with increased troponin level and a rare electrocardiogram (a single‑lead ST-elevation). Coronary angiography showed multi-vessel coronary artery disease. The patient underwent coronary angioplasty with drug-eluting stenting on left anterior descending coronary artery and drug eluting ballooning on first diagonal ostium. Coronary revascularization was completed with a staged stenting on left circumflex artery and right coronary artery. In rare cases of acute coronary syndrome, even isolated ST single lead anomalies may underlie multivessel coronary disease.

Electrocardiographic QRS Findings Upon Admission Can Predict Prognosis of Acute Myocardial Infarction Caused by Occlusion of Left Main Coronary Artery

BACKGROUND

Acute myocardial infarction (AMI) caused by left main coronary artery (LMCA) occlusion is associated with a severe clinical course and catastrophic consequences.

HYPOTHESIS

We sought to clarify ECG predictors of prognosis in AMI caused by LMCA occlusion.

METHODS

We examined 20 consecutive patients with AMI caused by LMCA occlusion that was treated by primary stenting. The patients were assigned to either a group that survived (S) and was discharged from hospital, or a group that did not survive (NS) and died in hospital. We compared ECG findings upon admission, angiographic findings, laboratory data and clinical outcomes.

RESULTS

The rate of having Thrombolysis In Myocardial Infarction (TIMI) grade > 2 coronary flow before PCI and of achieving TIMI grade 3 after PCI was significantly lower in the NS than the S group (14.3% vs. 83.3%, p = 0.003 and 35.7% vs. 100%, p = 0.008). The ECG findings showed longer QRS interval in the NS than in the S group (150.5 ± 37.9 vs. 105.2 ± 15.4, p = 0.022). A QRS interval ≥ 120 msec predicted in-hospital mortality with sensitivity, specificity and positive and negative predictive values of 78.5%, 100%, 100% and 66.7%, respectively, in this population.

CONCLUSIONS

The QRS duration upon admission was a good predictor of in-hospital mortality among patients with AMI caused by LMCA occlusion. This ECG sign could be useful in the emergency clinical setting.

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.

Entire process of electrocardiogram recording of Wellens syndrome: A case report

BACKGROUND

Wellens syndrome is an electrocardiogram (ECG) pattern seen in high-risk patients with unstable angina pectoris. It is characterized by inverted or biphasic T-waves that change into positive or pseudo-normalized waves at precordial leads when the patient experiences an angina attack; however, the mechanism for this condition remains unclear.

CASE SUMMARY

A 47-year-old male patient experienced repeated, unprovoked episodes of chest pain for > 20 d, with worsening during the previous day. On the day of admission, he experienced episodes of paroxysmal chest pain lasting more than 30 min, in addition to radiating pain to the left arm and exertional dyspnea. The patient presented to the emergency department with no chest pain or other discomfort at that time. ECG at presentation showed sinus tachycardia and T-wave changes, which were identified as Wellens syndrome when combined with previous ECG findings. ECGs and myocardial enzymology examinations were normal when angina was present, but the ECG showed inverted or biphasic T-waves when angina was absent. After percutaneous coronary intervention, the ECGs demonstrated inverted or biphasic T-waves in the anterior precordial leads on days 0, 1, and 2, but normal T-waves on day 3. The ECGs showed no subsequent ischemic ST-T-wave changes.

CONCLUSION

The Wellens syndrome pseudo-normalized T-waves likely reflect development of unstable angina pectoris into the hyperacute phase of ST-segment elevation myocardial infarction.

Electrocardiographic findings in true acute left main coronary total occlusion a subanalisys from ATOLMA registry

INTRODUCTION

Acute total occlusion of the left main coronary artery (ATOLMA) usually leads to a catastrophic presentation. Prediction of ATOLMA by electrocardiogram (ECG) may contribute to early detection and reperfusion. Limited data have been reported previously. This study aims to identify the admission 12‑leads ECG features that can predict the presence of ATOLMA and in-Hospital mortality in these patients.

METHODS

The admission ECGs findings in 24 patients from the previously reported ATOLMA multicenter registry were compared to the ECGs findings in 15 patients with an acute subtotal occlusion of the left main (ASOLMA) and to 15 patients with anterior ST-elevation myocardial infarction of the proximal left anterior descending (LADp-STEMI).

RESULTS

Some ECG features at presentation can predict an ATOLMA: QRS left axis deviation (-61.17 ± 9 degrees); ST-segment elevation in aVL (1.9 ± 0.65 mm); absence of ST-segment elevation in V1 (0.0 ± 0.6 mm); bifascicular block (58%); fragmented QRS (62.5%); prolongation of QTc interval (465 ± 19 ms) and of QRS interval (136 ± 12 mm). The multivariate analysis found that the independent predictors to distinguish ATOLMA from ASOLMA were aVL ST-segment deviation (OR 5.6(95% CI 1.5-21), p = 0.01) and absence of V1 ST-segment elevation (OR 27(95% CI 1.4-52), p = 0.01); and from LADp-STEMI was QRS width (OR 1.1(95% CI 1.02-1.2), p = 0.02). Fragmented QRS was the only independent predictor of in-hospital mortality in ATOLMA (OR 0.125(95% CI 0.01-0.81), p = 0.03).

CONCLUSIONS

aVL ST-segment elevation, the absence of V1 ST-segment elevation, left axis deviation, the presence of bifascicular block, and prolongation of QRS and QTc interval are predictors of ATOLMA. Fragmented QRS predicts in-hospital mortality in ATOLMA.

Chest pain showing precordial ST-segment elevation in a 96-year-old woman with right coronary artery occlusion: A case report

BACKGROUND

Typically, right coronary artery (RCA) occlusion causes ST-segment elevation in inferior leads. However, it is rarely observed that RCA occlusion causes ST-segment elevation only in precordial leads. In general, an electrocardiogram is considered to be the most important method for determining the infarct-related artery, and recognizing this is helpful for timely discrimination of the culprit artery for reperfusion therapy. In this case, an elderly woman presented with chest pain showing dynamic changes in precordial ST-segment elevation with RCA occlusion.

CASE SUMMARY

A 96-year-old woman presented with acute chest pain showing precordial ST-segment elevation with dynamic changes. Myocardial injury markers became positive. Coronary angiography indicated acute total occlusion of the proximal nondominant RCA, mild atherosclerosis of left anterior descending artery and 75% stenosis in the left circumflex coronary artery. Percutaneous coronary intervention was conducted for the RCA. Repeated manual thrombus aspiration was performed, and fresh thrombus was aspirated. A 2 mm × 15 mm balloon was used to dilate the RCA with an acceptable angiographic result. The patient’s chest pain was relieved immediately. A postprocedural electrocardiogram showed alleviation of precordial ST-segment elevation. The diagnosis of acute isolated right ventricular infarction caused by proximal nondominant RCA occlusion was confirmed. Echocardiography indicated normal motion of the left ventricular anterior wall and interventricular septum (ejection fraction of 54%), and the right ventricle was slightly dilated. The patient was asymptomatic during the 9-mo follow-up period.

CONCLUSION

Cardiologists should be conscious that precordial ST-segment elevation may be caused by occlusion of the nondominant RCA.

The prognostic significance of a positive or isoelectric T wave in lead aVR in patients with acute coronary syndrome and ischemic ECG changes in the presenting ECG - Long-term follow-up data of the TACOS study

BACKGROUND

A positive T wave in lead aVR (aVRT+) is an independent prognostic predictor of cardiovascular mortality in the general population as well as in cardiovascular disease.

SUBJECTS AND METHODS

We evaluated the prognostic impact of aVRT+ in an ECG recorded as close to hospital discharge as possible in acute coronary syndrome patients (n = 527). We divided the patients into three categories based on the findings in the admission ECG: ST elevation, global ischemia and other ST/T changes.

RESULTS

In the whole study population, and in all the three ECG subgroups, the 10-year all-cause mortality rate was higher in the aVRT+ group than in the aVRT- group. In Cox regression analysis, the age and gender adjusted hazard ratio (HR) for aVRT+ to predict all-cause mortality in the whole study population was 1.43 (95% confidence interval [CI] 1.12-1.83; p = 0.004). To predict cardiovascular mortality, the age and gender adjusted HR for aVRT+ was 1.54 (95% CI 1.14-2.07; p = 0.005) in the whole study population and 2.07 (95% CI 1.07-4.03; p = 0.032) in the category with other ST/T changes.

CONCLUSION

In ACS patients with or without ST elevation, but with ischemic ST/T changes in their presenting ECG, a positive or isoelectric T wave in lead aVR in an ECG recorded in the subacute in-hospital stage is associated with all-cause and cardiovascular mortality during long-term follow-up. Clinicians should pay attention to this simple ECG finding at hospital discharge.

Why complicate an important task? An orderly display of the limb leads in the 12-lead electrocardiogram and its implications for recognition of acute coronary syndrome

Background

In the standard ECG display, limb leads are presented in a non-anatomical sequence: I, II, III, aVR, aVL, aVF. The Cabrera system is a display format which instead presents the limb leads in a cranial/left-to-caudal/right sequence, i.e. in an anatomically sequential order. Lead aVR is replaced in the Cabrera display by its inverted version, −aVR, which is presented in its logical place between lead I and lead II.

Main text

In this debate article possible implications of using the Cabrera display, instead of the standard, non-contiguous lead display, are presented, focusing on its use in patients with possible acute coronary syndrome. The importance of appreciating reciprocal limb-lead ECG changes and the diagnostic and prognostic value of including aVR or lead −aVR in ECG interpretation in acute coronary syndrome is covered. Illustrative cases and ECGs are presented with both the standard and contiguous limb lead display for each ECG.

A contiguous lead display is useful when diagnosing acute coronary syndrome in at least 3 ways: 1) when contiguous leads are present adjacent to each other, identification of ST elevation in two contiguous leads is simple; 2) a contiguous lead display facilitates understanding of lead relationships as well as reciprocal changes; 3) it makes the common neglect of lead aVR unlikely.

Conlusions

It is logical to display the limb leads in their sequential anatomical order and it may have advantages both in diagnostics and ECG learning.

Successful resuscitation with extracorporeal membrane oxygenation support for refractory ventricular fibrillation caused by left main coronary artery occlusion

Refractory ventricular fibrillation with cardiac arrest caused by occlusion of the left main coronary artery may rapidly become fatal. In this report, we describe the case of a 70-year-old male who presented to emergency department with chest pain. Electrocardiogram showed ST-segment elevation in leads aVR and aVL and ST-segment depression in leads v3, v4, v5, v6, 2, 3, and aVF. Occlusion of the left main coronary artery was suspected. While waiting for percutaneous coronary intervention, the patient experienced sudden refractory ventricular fibrillation with cardiac arrest. In the emergency department, resuscitation of a patient with refractory ventricular fibrillation caused by occlusion of the left main coronary artery and ongoing cardiopulmonary resuscitation is a clinical challenge. Resuscitation with extracorporeal membrane oxygenation support was initiated approximately 35 min after prolonged conventional cardiopulmonary resuscitation. Emergency coronary angiography showed almost total occlusion of the left main coronary artery. Percutaneous coronary intervention with a stent restored coronary perfusion. The patient was discharged on day 6 without serious sequelae or neurological deficits.

Electrocardiographic changes in patients with acute myocardial infarction caused by left main trunk occlusion

BACKGROUND

Left main trunk (LMT) occlusion is a rare angiographic finding. The primary purpose was to investigate the ECG pattern of patients with angiographic confirmation of LMT as culprit lesion.

METHODS

Forty-eight patients (32 men; mean age 73 years) with angiographic total (21 patients; 44%) or subtotal (27 patients; 56%) occlusion of the LMT were analyzed. Twenty patients (42%) were found to have concomitant coronary lesions. Eighteen patients (38%) required intra-aortic balloon pump support.

RESULTS

A significant left axis deviation was observed in 26 cases (54%) and an intraventricular conduction delay in 32 patients (67%). The average QRS width and QTc interval were 122 and 433 ms, respectively. ST-segment elevation in lead aVR occurred in 32 patients (67%). ST-segment elevation in leads V2-5 and in leads I and aVL [classic left anterior descending (LAD) type] was frequently observed (18 cases; 35%). In six patients (13%), a partial LAD type was observed with ST-segment elevation in leads I and aVL, but not in peripheral leads. The remaining patients showed ST-segment elevation only in peripheral leads (12 cases), in inferior leads III + aVF (six cases), whereas six patients had no ST-segment elevation. Diffuse ST-segment depression only (>6 leads) was observed in 15 cases (31%). Eighteen patients (38%) died during hospitalization.

CONCLUSION

ST-segment elevation in lead aVR or a LAD-type pattern can be associated with LMT disease. Other relevant aspects are the presence of cardiogenic shock at admission, the left axis deviation and marked prolongation of QTc interval and QRS width.

Acute total occlusion of the left main coronary artery treated with percutaneous intervention and simultaneous implantation of intra-aortic balloon pump

Electrocardiographic findings at first medical contact and direct transfer to the catheterization laboratory are important in acute total occlusion of the left main coronary artery. Simultaneous emergency angioplasty and intra‐aortic balloon pump implantation might be beneficial in overcoming the patient's most critical hemodynamic instability.

Electrocardiographic characteristics associated with in-hospital outcome in patients with left main acute coronary syndrome: For contriving a new risk stratification score

AIM

The aim of this study was to evaluate electrocardiographic characteristics associated with in-hospital prognosis in patients with left main acute coronary syndrome.

METHODS AND RESULTS

A total of 89 left main acute coronary syndrome subjects were selected from 3357 consecutive acute coronary syndrome patients (2.7%). Patients of this study were divided into two groups; those who survived and those who died. Patients' characteristics and electrocardiogram on admission were then retrospectively analyzed between the two groups. In-hospital mortality was 28.1%. The prevalence and degree of ST-segment elevation at lead aVL were significantly higher in the deceased group than in the survival group ( p<0.001). However, those at lead aVR did not show significant differences between the two groups. Moreover, the width of the QRS-complex was significantly wider (lead V3; p<0.001), and the level of five minus the absolute value of five minus number of ST-segment elevation (5-|5-ST|; due to the highest in-hospital mortality (70%) in the five-lead ST-segment elevation group) was significantly larger in the deceased group than in the survival group ( p<0.001). The odds ratios that predicted in-hospital cardiac death were 1.03 for width of the QRS-complex at lead V3 (95% confidence interval (CI); 1.01-1.06; p=0.003), 1.74 for 5-|5-ST| (95% CI; 1.03-3.00; p=0.040), and 1.44 for ST-segment elevation at lead aVL (95% CI; 0.93-2.23; p=0.100).

CONCLUSIONS

ST-segment elevation at lead aVL rather than aVR, width of the QRS-complex at lead V3 and number of ST-segment elevation were the prognostic predictors for in-hospital mortality in patients with left main acute coronary syndrome. Electrocardiographic characteristics should be assessed in addition to the established risk score in patients with left main acute coronary syndrome.

Incidence, treatment strategies and outcomes of acute coronary syndrome with and without ongoing myocardial ischaemia: results from the CZECH-3 registry

BACKGROUND

Patients with acute coronary syndrome with signs of ongoing myocardial ischaemia at first medical contact should be indicated for immediate invasive treatment.

AIM

To assess the incidence, treatment strategies and outcomes of acute coronary syndrome in a large unselected cohort of patients with respect to the signs of ongoing myocardial ischaemia.

METHODS

The CZECH-3 registry included 1754 consecutive patients admitted for suspected acute coronary syndrome to 43 hospitals during a 2-month period in the autumn of 2015. Acute coronary syndrome with ongoing myocardial ischaemia was defined by the presence of persistent/recurrent chest pain/dyspnoea and at least one of the following: persistent ST-segment elevation or depression, bundle branch block, haemodynamic or electric instability due to suspected ischaemia. Major adverse cardiac events (death, reinfarction, stroke, unexpected revascularisation, stent thrombosis) and severe bleeding according to Bleeding Academic Research Consortium criteria were evaluated at 30 days.

RESULTS

Acute coronary syndrome was ruled out during the hospital stay in 434 (24.7%) patients. Out of 1280 patients with confirmed acute coronary syndrome, 732 (57%) had clinical signs of ongoing myocardial ischaemia at first medical contact. Coronary angiography was performed in 94.7% of patients with confirmed acute coronary syndrome with ongoing myocardial ischaemia and 89% of patients with confirmed acute coronary syndrome without ongoing myocardial ischaemia (P<0.001). The major adverse cardiac event rate was 9.8% for patients with confirmed acute coronary syndrome with ongoing myocardial ischaemia and 5.5% for patients without ongoing myocardial ischaemia (P=0.005), the 30-day severe bleeding rate was 1.6% and 1.5% (P=1.0). Patients with ongoing myocardial ischaemia admitted to regional hospitals had higher major adverse cardiac event rates compared with patients admitted directly to cardiocentres with percutaneous coronary intervention capability (13.3% vs. 8.2%, P=0.034).

CONCLUSIONS

Ongoing myocardial ischaemia was present in more than half of patients hospitalised with acute coronary syndrome. These very high-risk patients may benefit from direct admission to percutaneous coronary intervention-capable centres.

Pitfalls in Electrocardiographic Diagnosis of Acute Coronary Syndrome in Low-Risk Chest Pain

Less than half of patients with a chest pain history indicative of acute coronary syndrome have a diagnostic electrocardiogram (ECG) on initial presentation to the emergency department. The physician must dissect the ECG for elusive, but perilous, characteristics that are often missed by machine analysis. ST depression is interpreted and often suggestive of ischemia; however, when exclusive to leads V1–V3 with concomitant tall R waves and upright T waves, a posterior infarction should first and foremost be suspected. Likewise, diffuse ST depression with elevation in aVR should raise concern for left main- or triple-vessel disease and, as with the aforementioned, these ECG findings are grounds for acute reperfusion therapy. Even in isolation, certain electrocardiographic findings can suggest danger. Such is true of the lone T-wave inversion in aVL, known to precede an inferior myocardial infarction. Similarly, something as ordinary as an upright and tall T wave or a biphasic T wave can be the only marker of ischemia. ECG abnormalities, however subtle, should give pause and merit careful inspection since misinterpretation occurs in 20–40% of misdiagnosed myocardial infarctions.

Predictive Value of Exercise Stress Test-Induced ST-Segment Changes in Leads V1 and avR in Determining Angiographic Coronary Involvement

BACKGROUND

The significance of electrocardiographic changes during exercise tolerance testing for distinguishing occluded artery is not well known. We tried to determine the role of ST elevation in leads aVR and V1 during exercise in detecting stenosis of left main coronary artery and proximal left anterior descending artery.

METHODS

ST segment changes during exercise in 230 patients, who underwent diagnostic angiography, were documented. The association of ST elevation in lead aVR, V1 , leads aVR + V1 , and STE in leads aVR + V1 with ST depression in other leads with pattern of coronary stenosis were investigated.

RESULTS

Left main and proximal left anterior artery stenosis were more common in patients with ST elevation in lead aVR (P < 0.001 for both). Similar association was found in the presence of ST elevation in lead V1 . The presence of ST elevation ≥1 mm in lead aVR had a sensitivity of 100% and 94.3% for detecting left main and left anterior descending artery stenosis, respectively. The specificity was 33.5% and 26.6%, respectively. ST elevation in leads aVR + V1 had a sensitivity of 74.4% and 65.9% and a specificity of 68.5% and 64.4% for detecting left main and left anterior descending arteries stenosis, respectively.

CONCLUSION

ST elevation in lead aVR is highly sensitive for left main and proximal left anterior descending artery lesions. Using ST elevation in lead V1 in addition to lead aVR as a positive finding increases the specificity with a further decrease in sensitivity.

Prehospital diagnosis of patients with acute myocardial infarction

Primary percutaneous intervention (PPCI) is the preferred treatment in patients with ST elevation myocardial infarction (STEMI) if this can be performed in a timely manner. The

[Typical atypical ECGs and anterior wall infarction : Subtle signs of an acute coronary artery occlucion]

The ECG is a very important diagnostic tool if an acute coronary syndrome is suspected. It should be performed immediately when medical staff contacts the patient. If an ST elevation myocardial infarction (STEMI) is diagnosed, immediate reperfusion of the occluded vessel should be the primary goal. Therefore, even subtle signs of an anterior wall infarction diagnosed by the ECG which lead to suspicion of complete occlusion of a coronary artery should be known and diagnosed by all physicians who may have contact with these types of patients. The ECG variations presented in this article can be used as a sample for medical personnel who are not familiar with these changes and do not routinely interpret ECGs.

Clinical Predictors for Delayed or Inappropriate Initial Diagnosis of Type A Acute Aortic Dissection in the Emergency Room

BACKGROUND

Initial diagnosis of acute aortic dissection (AAD) in the emergency room (ER) is sometimes difficult or delayed. The aim of this study is to define clinical predictors related to inappropriate or delayed diagnosis of Stanford type A AAD.

METHODS

We conducted a retrospective analysis of 127 consecutive patients with type A AAD who presented to the ER within 12 h of symptom onset (age: 69.0 ± 15.4 years, male/female = 49/78). An inappropriate initial diagnosis (IID) was considered if AAD was not included in the differential diagnosis or if chest computed tomography or echocardiography was not performed as initial imaging tests. Clinical variables were compared between IID and appropriate diagnosis group. The time to final diagnosis (TFD) was also evaluated. Delayed diagnosis (DD) was defined as TFD > third quartile. Clinical factors predicting DD were evaluated in comparison with early diagnosis (defined as TFD within the third quartile). In addition, TFD was compared with respect to each clinical variable using a rank sum test.

RESULTS

An IID was determined for 37% of patients. Walk-in (WI) visit to the ER [odds ratio (OR) 2.6, 95% confidence interval (CI) = 1.01-6.72, P = 0.048] and coronary malperfusion (CM, OR = 6.48, 95% CI = 1.14-36.82, P = 0.035) were predictors for IID. Overall, the median TFD was 1.5 h (first/third quartiles = 0.5/4.0 h). DD (>4.5 h) was observed in 27 cases (21.3%). TFD was significantly longer in WI patients (median and first/third quartiles = 1.0 and 0.5/2.85 h for the ambulance group vs. 3.0 and 1.0/8.0 h for the WI group, respectively; P = 0.003). Multivariate analysis revealed that WI visit was the only predictor for DD (OR = 3.72, 95% CI = 1.39-9.9, P = 0.009). TFD was significantly shorter for appropriate diagnoses than for IIDs (1.0 vs. 6.0 h, respectively; P < 0.0001).

CONCLUSIONS

WI visit to the ER and CM were predictors for IID, and WI was the only predictor for DD in acute type A AAD in the community hospital.

Effects of different LAD-blocked sites on the development of acute myocardial infarction and malignant arrhythmia in a swine model

OBJECTIVE

To explore the effects of various left anterior descending (LAD) artery-blocked sites on the development of acute myocardial infarction (AMI) and malignant arrhythmia in a swine model.

METHODS

Twenty-two pigs underwent occlusion of the coronary artery with balloon angioplasty were randomly divided into three groups according to the blocked site of the balloon: middle-site-blocked LAD group, bottom-third-blocked LAD group and control group. Then, the development of AMI and malignant arrhythmia, including ventricular tachycardia and ventricular fibrillation during the process of model creation, were recorded. Changes of the hemodynamics, blood gas analysis, electrocardiography, and myocardial enzymes were analyzed in each group before and after occlusion.

RESULTS

Middle-site-LAD blockage resulted in a larger infarction size and the corresponding incidence of ventricular fibrillation was significantly higher than that of the bottom-third-blocked group (P<0.05). After the occlusion, the QTc interval of the Middle-site-blocked LAD group was significantly longer than that in the other groups (P<0.01). Moreover, mean arterial blood pressure (MAP), left ventricular ejection fraction (LVEF), and partial pressure of oxygen (PaO2) were significantly lower, but partial pressure of carbon dioxide (PaCO2) increased, in the Middle-site-blocked-LAD group compared with that in the bottom-third-blocked group (P<0.01). Compared with the control group, the two LAD-blocked groups showed significantly higher levels of Mb, CK-MB, LDH, AST and cTnT (P<0.01) four hours after the artery occlusion. However, these indexes were not significantly different between the two LAD-blocked groups (P>0.05).

CONCLUSIONS

Location of LAD blockages in swine models may affect the development of AMI and malignant arrhythmia.

Significance of lead aVR in acute coronary syndrome

The 12-lead electrocardiogram (ECG) is a crucial tool in the diagnosis and risk stratification of acute coronary syndrome (ACS). Unlike other 11 leads, lead aVR has been long neglected until recent years. However, recent investigations have shown that an analysis of ST-segment shift in lead aVR provides useful information on the coronary angiographic anatomy and risk stratification in ACS. ST-segment elevation in lead aVR can be caused by (1) transmural ischemia in the basal part of the interventricular septum caused by impaired coronary blood flow of the first major branch originating from the left anterior descending coronary artery; (2) transmural ischemia in the right ventricular outflow tract caused by impaired coronary blood flow of the large conal branch originating from the right coronary artery; and (3) reciprocal changes opposite to ischemic or non-ischemic ST-segment depression in the lateral limb and precordial leads. On the other hand, ST-segment depression in lead aVR can be caused by transmural ischemia in the inferolateral and apical regions. It has been recently shown that an analysis of T wave in lead aVR also provides useful prognostic information in the general population and patients with prior myocardial infarction. Cardiologists should pay more attention to the tracing of lead aVR when interpreting the 12-lead ECG in clinical practice.

Acute coronary syndromes presenting with transient diffuse ST segment depression and st segment elevation in lead aVR not caused by "acute left main coronary artery occlusion": description of two cases

BACKGROUND

Diffuse ST-segment depression in the inferior + anterolateral leads with ST-segment elevation in lead aVR has been described as characteristic of diffuse circumferential subendocardial ischemia caused by acute subtotal occlusion of the left main coronary artery.

METHODS

Here we describe two patients admitted for acute neurological disorders who developed transient diffuse ST-segment depression in the inferior + anterolateral leads with ST-segment elevation in lead aVR, associated with elevation of cardiac troponin-I.

RESULTS

In both cases subsequent coronary angiography did not show significant left main stenosis or "left main equivalent" narrowings.

CONCLUSIONS

As both patients had acute neurological disorders, a possible association between the two conditions is discussed.

A Case of Acute Myocardial Infarction With ST-Segment Elevation in a Lead Augmented Right Vector Caused by a Left Main Coronary Artery Vasospasm

Diagnosing and selecting an appropriate treatment strategy for left main coronary artery (LMCA) obstruction is very important. Although this disease is not frequently encountered, it can cause severe hemodynamic deterioration resulting in a less favorable prognosis without a suitable management approach. Another aspect of LMCA that we must not overlook is coronary artery spasm, which can be an infrequent but important cause of acute coronary syndrome. Although it is rare, LMCA can cause critical complications. In this study, we report the case of a 35-year-old female who was admitted to the hospital with a diagnosis of acute myocardial infarction with ST-segment elevation in the aVR lead caused by a left main coronary spasm that was examined on intravascular ultrasound.

Improved detection of acute myocardial infarction in patients with chest pain and significant left main stem coronary stenosis

BACKGROUND

Non-invasive diagnosis of acute myocardial infarction (AMI) associated with significant left main stem (LMS) stenosis remains challenging.

METHODS

Consecutive patients presenting with acute ischaemic-type chest pain from 2000 to 2010 were analysed. Entry criteria: 12-lead ECG and Body Surface Potential Map (BSPM) at presentation, cardiac troponin T (cTnT) ≥12 h and coronary angiography during admission. cTnT ≥0.03 µg/l defined AMI. ECG abnormalities assessed: STEMI by Minnesota criteria; ST elevation (STE) aVR ≥0.5 mm; ST depression (STD) ≥0.5 mm in ≥2 contiguous leads (CL); T-wave inversion (TWI) ≥1 mm in ≥2 CL. BSPM STE was ≥2 mm in anterior, ≥1 mm in lateral, inferior, right ventricular or high right anterior and ≥0.5 mm in posterior territories. Significant LMS stenosis was ≥70%.

RESULTS

Enrolled were 2810 patients (aged 60 ± 12 years; 71% male). Of these, 116 (4.1%) had significant LMS stenosis with AMI occurring in 92 (79%). STEMI by Minnesota criteria occurred in 13 (11%) (sensitivity 12%, specificity 92%), STE in lead aVR in 23 (20%) (sensitivity 23%, specificity 92%), TWI in 38 (33%) (sensitivity 34%, specificity 71%) and STD in 51 (44%) (sensitivity 49%, specificity 75%). BSPM STE occurred in 85 (73%): sensitivity 88%, specificity 83%, positive predictive value 95% and negative predictive value 65%. Of those with AMI, 74% had STE in either the high right anterior or right ventricular territories not identified by the 12-lead ECG. C-Statistic for AMI diagnosis using BSPM STE was 0.800 (P < 0.001).

CONCLUSION

In patients with significant LMS stenosis presenting with chest pain, BSPM STE has improved sensitivity (88%), with specificity 83%, over 12-lead ECG in the diagnosis of AMI.

The presence of ST-elevation in lead aVR predicts significant left main coronary artery stenosis in cardiogenic shock resulting from myocardial infarction: the Manitoba cardiogenic shock registry

INTRODUCTION

Electrocardiographic (ECG) predictors of significant angiographic left main coronary artery stenosis (LMCS>50%) have been described in acute myocardial infarction using ST-segment elevation in lead aVR (aVR-STE). However, there is a paucity of data on its association with LMCS>50% in the setting of cardiogemic shock (CGS).

METHODS

We investigated 210 consecutive, unselected, patients from Sept. 2002-2006 with CGS due to acute myocardial infarction undergoing cardiac catheterization. Of those, 191 patients with interpretable ECG tracings for aVR-STE analysis formed our study sample. aVR-STE was defined as ST-segment elevation≥1mm in aVR while LMCS>50% on coronary angiogram was defined as any left main lesion that demonstrated >50% lumen narrowing or equivalent by direct visualization or quantitative coronary angiography analysis.

RESULTS

There was 59% survival to discharge of this predominantly male cohort (median age 68±12years; 31% females). Fifty three (28%) cases had aVR-STE while 27 (14%) had LMCS>50%. Of those, 16 patients who had aVR-STE also had LMCS>50% (sensitivity 59%, specificity 77%, positive predictive value 30%, negative predictive value 92% for predicting LMCS>50%). Multivariate analysis revealed that aVR-STE was the only significant predictor of LMCS>50% was (p=0.014; Odds Ratio=3.06; 95% Confidence Interval 1.26-7.47).

CONCLUSION

In CGS due to acute myocardial infarction, aVR-STE>1mm proves to be an important predictor of LMCS>50%. Such data could be helpful in further risk stratification for optimal management during CGS.

ST-segment deviation in lead aVR on admission is not associated with left ventricular function at predischarge in first anterior wall ST-segment elevation acute myocardial infarction

Previous studies have shown that the analysis of ST-segment deviation in lead aVR on admission provides useful information on angiographic coronary anatomy and risk stratification in acute coronary syndromes. However, the association between ST-segment deviation in lead aVR on admission and left ventricular (LV) function has not been fully investigated in anterior wall acute ST-segment elevation myocardial infarction. In this study, 237 patients with first anterior wall acute ST-segment elevation myocardial infarction were examined. The patients were divided into the following 3 groups according to ST-segment deviation in lead aVR on admission: 85 with ST-segment elevation ≥0.5 mm (group A), 106 without ST-segment deviation (group B), and 46 with ST-segment depression ≥0.5 mm (group C). LV ejection fractions at predischarge were compared among the 3 groups. Among the 3 groups, there were significant differences in the prevalences of proximal left anterior descending coronary artery (LAD) occlusion (group A 75.3%, group B 56.6%, group C 45.7%, p = 0.002), long LAD (group A 27.1%, group B 31.1%, group C 56.5%, p = 0.002), and good collaterals to the LAD (group A 40.0%, group B 25.4%, group C 17.4%, p = 0.01). LV ejection fractions at predischarge did not differ among the 3 groups (group A 56.4 ± 12.5%, group B 56.9 ± 12.7%, group C 53.3 ± 12.2%, p = 0.26). On a multiple regression analysis, establishment of Thrombolysis In Myocardial Infarction grade 3 flow, proximal LAD occlusion, and long LAD were associated with the LV ejection fraction at predischarge. In conclusion, ST-segment deviation in lead aVR on admission is not associated with LV function at predischarge in first anterior wall acute ST-segment elevation myocardial infarction.

Cannabis, collaterals, and coronary occlusion

A 51-year-old gentleman, who regularly smoked cannabis, presented with chest pain and diaphoresis. He was haemodynamically stable. ECG showed ST depression, inferiorly, and 1 mm ST elevation in lead aVR. Emergent coronary angiography showed thrombotic occlusion of the left main coronary artery (LMCA), the dominant RCA provided Rentrop grade II collaterals to the LAD. The LMCA was successfully reopened by deployment of a bare-metal stent. Animal heart models suggest that endogenous cannibinoids may cause ischaemic preconditioning. This case suggests that the severity of ischaemia, and hence ECG changes and haemodynamic consequences following an acute occlusion of the LMCA, can be ameliorated by coronary collateralisation and possibly by preconditioning of the myocardium.

Evaluating the Role of a Triage Electrocardiogram Protocol at an Urban Emergency Department

Objective

Our emergency department (ED) performs triage ECG for a variety of complaints to identify patients in need of treatment escalation. The aim of this study was to evaluate the existing triage ECG protocol as a means of treatment decision making.

Methods

This prospective observational study was conducted in an urban ED over one week. We recruited all patients aged 18 years and above with an undiagnosed complaint requiring a triage ECG based on the existing departmental protocol. As part of the protocol, an experienced emergency doctor then reviewed the ECG to determine the need for treatment escalation. Explicit data collection was performed using our electronic database. The outcome measures were proportions of triage treatment escalations, reasons for escalation and disposition status. Analysis was by descriptive statistics.

Results

739 patients were recruited from a total attendance of 3228. The rate of triage ECG was 23%. There were 22 (3%) triage escalations. Usually each escalation resulted from a combination of reasons. These included important ECG changes (77%), abnormal vital signs (5%) and ongoing symptoms (95%).

Conclusions

The triage ECG protocol resulted in important escalations in a small proportion of presentations. Future research is needed to refine guidelines on the use of triage ECG for different ED complaints.