Prognostic significance of precordial ST segment depression during inferior myocardial infarction in the thrombolytic era: results in 16,521 patients

New Electrocardiographic Score for Predicting the Site of Coronary Artery Occlusion in Inferior Wall Acute Myocardial Infarction

Background

An electrocardiogram (ECG) was used to determine the type of acute myocardial infarction (MI) and locate the culprit vessel. Inferior wall myocardial infarction (IWMI) patients with the right coronary artery (RCA) as the culprit vessel may have a worse clinical prognosis than the left circumflex artery (LCx). We aimed to develop a new, simple, accurate scoring system to localize the RCA.

Methods

From January 2018 to January 2020, patients were admitted to the Department of Cardiology of TEDA International Cardiovascular Hospital and the Second Hospital of Tianjin Medical University due to IWMI and coronary angiography confirmed that the infarct-related vessel was a single RCA or LCx. ECG of patients before percutaneous coronary intervention (PCI) was collected to quantitatively analyze the characteristics of ST-segment deviation in non-inferior wall leads (N-IWL) and establish the RCA score in N-IWL.

Results

149 patients were enrolled, including 83 in the RCA group and 66 in the LCx group. Finally, ST-segment depression (ST↓) lead I, aVR, V1, and V6, and ST↓≥ 1mm in lead V4 were found to be associated with the location of the RCA. The sensitivity, specificity, and area under the curve (AUC) of the N-IWL RCA scoring system were 77.1%, 72.7%, and 0.83, respectively. The diagnostic ability of the scoring system was better than that of other algorithms and scoring systems.

Conclusion

ECG helps identify the RCA in patients with IWMI before PCI. The N-IWL RCA score may help identify the culprit vessel as the RCA in patients with IWMI.

A comprehensive and easy-to-use ECG algorithm to predict the coronary occlusion site in ST-segment elevation myocardial infarction

BACKGROUND

Several electrocardiogram (ECG) criteria have been proposed to predict the location of the culprit occlusion in specific subsets of patients presenting with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to develop, through an independent validation of currently available criteria, a comprehensive and easy-to-use ECG algorithm, and to test its diagnostic performance in real-world clinical practice.

METHODS

We analyzed ECG and angiographic data from 419 consecutive STEMI patients submitted to primary percutaneous coronary intervention over a one-year period, dividing the overall population into derivation (314 patients) and validation (105 patients) cohorts. In the derivation cohort, we tested >60 previously published ECG criteria, using the decision-tree analysis to develop the algorithm that would best predict the infarct-related artery (IRA) and its occlusion level. We further assessed the new algorithm diagnostic performance in the validation cohort.

RESULTS

In the derivation cohort, the algorithm correctly predicted the IRA in 88% of cases and both the IRA and its occlusion level (proximal vs mid-distal) in 71% of cases. When applied to the validation cohort, the algorithm resulted in 88% and 67% diagnostic accuracies, respectively. In a real-world comparative test, the algorithm performed significantly better than expert physicians in identifying the site of the culprit occlusion (P = .026 vs best cardiologist and P < .001 vs best emergency medicine doctor).

CONCLUSIONS

Derived from an extensive literature review, this comprehensive and easy-to-use ECG algorithm can accurately predict the IRA and its occlusion level in all-comers STEMI patients.

Characteristics and mechanism of reciprocal ST-segment depression in acute ST segment elevation myocardial infarction: Reciprocal ST-segment depression and ST segment elevation myocardial infarction

At present, the mechanism of reciprocal ST-segment depression (RSTD) is unclear. ST-segment changes may be caused by the potential difference between the positive and negative electrodes, although this requires further investigation. The characteristics of RSTD and their relationship with ST-segment elevation in acute ST segment elevation myocardial infarction (STEMI) patients were analyzed. We replaced the negative electrode of the precordial leads of an inferior wall myocardial infarction patient and observed the changes in the ST-segment of the precordial leads. A total of 85 patients were included, of which 75 were patients with RSTD. All 45 patients with inferior myocardial infarction had limb lead RSTD, and 37 had anterior lead ST-segment depression. All ST-segment changes in STEMI can be explained by the proposed mechanism, and the value of ST segment depression in limb leads can be calculated by the value of ST segment elevation. In summary, the mechanism of RSTD in acute myocardial infarction may be that the action potential (AP) of the negative electrode of the lead weakens or disappears and the AP of the positive electrode may not be completely offset, resulting in ST-segment depression. Animal experimental studies are needed for further confirmation. When the negative electrode of the precordial lead is changed in acute inferior wall myocardial infarction patient, the ST-segment of the precordial lead changes accordingly. All the changes are consistent with our analysis.

Assessment of Selected Baseline and Post-PCI Electrocardiographic Parameters as Predictors of Left Ventricular Systolic Dysfunction after a First ST-Segment Elevation Myocardial Infarction

OBJECTIVE

To assess the performance of ten electrocardiographic (ECG) parameters regarding the prediction of left ventricular systolic dysfunction (LVSD) after a first ST-segment-elevation myocardial infarction (STEMI).

METHODS

We analyzed 249 patients (74.7% males) treated with primary percutaneous coronary intervention (PCI) included into a single-center cohort study. We sought associations between baseline and post-PCI ECG parameters and the presence of LVSD (defined as left ventricular ejection fraction [LVEF] ≤ 40% on echocardiography) 6 months after STEMI.

RESULTS

Patients presenting with LVSD (n = 52) had significantly higher values of heart rate, number of leads with ST-segment elevation and pathological Q-waves, as well as total and maximal ST-segment elevation at baseline and directly after PCI compared with patients without LVSD. They also showed a significantly higher prevalence of anterior STEMI and considerably wider QRS complex after PCI, while QRS duration measurement at baseline showed no significant difference. Additionally, patients presenting with LVSD after 6 months showed markedly more severe ischemia on admission, as assessed with the Sclarovsky-Birnbaum ischemia score, smaller reciprocal ST-segment depression at baseline and less profound ST-segment resolution post PCI. In multivariate regression analysis adjusted for demographic, clinical, biochemical and angiographic variables, anterior location of STEMI (OR 17.78; 95% CI 6.45-48.96; p < 0.001), post-PCI QRS duration (OR 1.56; 95% CI 1.22-2.00; p < 0.001) expressed per increments of 10 ms and impaired post-PCI flow in the infarct-related artery (IRA; TIMI 3 vs. <3; OR 0.14; 95% CI 0.04-0.46; p = 0.001) were identified as independent predictors of LVSD (Nagelkerke's pseudo R2 for the logistic regression model = 0.462). Similarly, in multiple regression analysis, anterior location of STEMI, wider post-PCI QRS, higher baseline number of pathological Q-waves and a higher baseline Sclarovsky-Birnbaum ischemia score, together with impaired post-PCI flow in the IRA, higher values of body mass index and glucose concentration on admission were independently associated with lower values of LVEF at 6 months (corrected R2 = 0.448; p < 0.00001).

CONCLUSIONS

According to our study, baseline and post-PCI ECG parameters are of modest value for the prediction of LVSD occurrence 6 months after a first STEMI.

ST-segment depression in left precordial leads in electrocardiogram of patients with acute inferior myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

The early identification of patients with acute inferior ST-segment elevation myocardial infarction (STEMI) with high risk features is particularly important. Acute inferior STEMI may be associated with ST-segment depression in the left precordial leads (V4-V6). This study assessed prognostic value of ST-segment depression in these left precordial leads during the admission of patients with acute inferior STEMI treated with primary percutaneous coronary intervention.

METHODS

This retrospective study enrolled 1,374 patients with acute inferior STEMI who underwent primary percutaneous coronary angioplasty between March 2011 and June 2014. The patients were divided into two groups: one group (n = 687) with left precordial ST-segment depression and the other (n = 687) without such ST-segment changes.

RESULTS

The patients with left precordial ST-segment depression were older and had higher incidence of hypertension, diabetes mellitus, and higher levels of troponin. In-hospital mortality was higher in patients with left precordial ST-segment depression. Advanced coronary artery disease was more observed in these patients.

CONCLUSION

In patients with acute inferior STEMI treated with primary coronary intervention, left precordial ST-segment depression during admission of ECG is associated with more advanced coronary artery disease, and worse in-hospital clinical outcomes.

Correlation of ST changes in leads V4-V6 to area of ischemia by CMR in inferior STEMI

OBJECTIVE

We aim to determine the correlation between ST-segment changes in leads V4-V6 and the extent of myocardial injury by cardiac magnetic resonance (CMR) in patients with inferior ST elevation (STE) myocardial infarction (iSTEMI).

DESIGN

Admission electrocardiogram and CMR data from the MITOCARE trial were used. Differences in mean myocardium at risk, infarct size, ejection fraction and myocardial segment involvement by CMR were compared in patients with first iSTEMI with STE, ST depression (STD) or no ST changes (NST) in V4-V6. Myocardial segment involvement was further evaluated by comparing proportion of patients in each group with ≥25% and ≥50% segment involvement.

RESULTS

Fifty-four patients were included. Patients with STE (n = 22) and STD (n = 16) in V4-V6 had significantly lower ejection fraction compared to NST (n = 16) (48% vs 48% vs 54%, p = .02). STE showed more apical, apical lateral and mid-inferolateral involvement but less basal inferior involvement than NST. STD exhibited greater basal inferoseptal involvement compared to STE. There were more patients with STE that had ≥25% and ≥50% apical lateral involvement compared with STD and NST groups. Patients with STD were more likely to have ≥25% and ≥50% basal inferoseptal involvement compared with STE and NST groups.

CONCLUSION

Our study suggests that in iSTEMI, ST changes in the precordial leads V4-V6 correlates with greater myocardial injury and distribution of myocardium at risk.

Prognostic Predictive Values of the Initial Electrocardiogram with St-Segment Elevation Acute Myocardial Infarction in Chinese Patients

Objective

To study the electrocardiogram (ECG) features that predict 30-day mortality of ST-segment elevation acute myocardial infarction (STEMI) in Chinese patients.

Method

This was a retrospective study. Patients presenting within twelve hours after the onset of chest pain with ECG features compatible with STEMI and the diagnosis confirmed after admission were included in the study. Data taken into account included age, sex and thrombolytic therapy in the emergency department. The hospital records of the patients were later retrieved from the computer. The initial ECG performed in the emergency department were reviewed.

Results

A total of 98 patients were included in the study. There was no statistically significant relationship between 30-day mortality and the type of myocardial infarction or the magnitude of the ST segment changes. Distortion of the terminal portion of the QRS complex and prior evidence of myocardial infarction (in another location different from the presenting one) showed statistically significant relationship with 30-day mortality, with odds ratio 10.364 (95% CI 1.715–62.620) and 12.731 (95% CI 2.317–69.962) respectively.

Conclusion

In newly diagnosed STEMI patients, if there is evidence of terminal distortion of the QRS complex or prior ECG changes of myocardial infarction, the 30-day mortality will be significantly higher.

Correlation of Reciprocal Changes and QRS Amplitude in ECG to Left Ventricular Dysfunction, Wall Motion Score and Clinical Outcome in First Time ST Elevation Myocardial Infarction

INTRODUCTION

Electrocardiogram (ECG) is the simplest tool for diagnosing ST Elevation Myocardial Infarction (STEMI). We can use a12 lead ECG for prognostication purposes also.

AIM

The aim of the study was to find out the role of ECG as a prognostic marker in terms of clinical outcome and wall motion abnormality.

MATERIALS AND METHODS

It was a prospective study done in PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India, from January 2014 to September 2014. Patients aged above 18 years admitted with first episode of ST EMI as per the inclusion and exclusion criteria were recruited for the study. Presence of reciprocal changes and QRS amplitude was measured from ECG. Presence of Left Ventricular Dysfunction (LVD) and wall motion score were calculated from ECG along with clinical outcome during first follow up visit. Statistical analysis was done using SPSS software. Probability was calculated using chi-square test, independent t-test and ANOVA analysis.

RESULTS

A total of 120 patients were recruited for the study of which six were excluded based on the exclusion criteria. Among 114 patients analysed, 55 had reciprocal changes; 38 of them developed LVD which was statistically significant (p=0.002). Of the 78 patients with Anterior Wall Myocardial Infarction (AWMI), 35 had reciprocal changes; 15 (42.9%) of them had NYHA Class 1 symptoms, 14 (40%) had Class II and 4 (11%) had class III symptoms at follow up. The association was statistically significant (p=0.001). Similar statistically significant association was found in patients with Inferior Wall Myocardial Infarction (IWMI) who had reciprocal changes and NYHA symptoms at follow up (p=0.004). The mean wall motion score in patients with AWMI and reciprocal changes was 24.83 ± 4.1; whereas, without reciprocal changes was 23.98 ± 3.6; the association was not statistically significant. The mean QRS amplitude of all patients with LVD was 33.25 ±16.34. The association between QRS amplitude and LVD was not statistically significant. The overall mean wall motion score was 24.86 ± 3.91. The association between QRS amplitude and wall motion score was statistically significant (r value = 0.210). The association between QRS amplitude and wall motion score was statistically significant when we analysed AWMI (r= -0.147, p=0.199) and IWMI (r= -0.359, p=0.031) separately.

CONCLUSION

ECG can be used as a tool for prognostication in acute STEMI. The presence of reciprocal changes in the ECG can signify poorer outcome on follow up. Lower QRS amplitude can be used as a predictor of larger infarct.

Interactions Between Reciprocal ST-Segment Downsloping During ST-Elevated Myocardial Infarction and Global Cardiac Perfusion and Functional Abnormalities

Reciprocal ST-segment downsloping on electrocardiogram is a frequent finding during ST-elevated myocardial infarction (STEMI), but its etiology is still disputed. We sought to evaluate the relation between reciprocal ST-segment downsloping during STEMI and major cardiac perfusion and functional parameters. One hundred eighty-five patients with STEMI underwent emergency coronary angiography. The presence of reciprocal ST-segment downsloping was assessed. At coronary angiography, the corrected TIMI frame count (cTFC) was computed both on culprit and remote vessels and the occurrence of "no/slow reflow" phenomenon after percutaneous coronary intervention (PCI) identified. The left ventricular wall motion score index ratio (discharge/admission values) at echocardiography and the slope of high-sensitivity troponin elimination were computed as measures of effective myocardial reperfusion. Reciprocal ST-segment downsloping was revealed in 91 patients (49%). They presented higher cTFC values on remote vessels than patients without reciprocal electrocardiographic abnormalities (44 ± 18 vs 37 ± 15 cineframes × second^-1, p = 0.004). The presence of remote ST-segment downsloping was also associated with a higher prevalence of "no/slow reflow" phenomenon (59% vs 40%, p = 0.013) as well as more abnormal values of wall motion score index ratio (p = 0.042) and high-sensitivity troponin slope (p = 0.012). At multivariate analyses, a higher cTFC on remote vessels predicted the occurrence of reciprocal ST-segment changes (p = 0.018) and the development of "no/slow reflow" phenomenon after PCI (p = 0.005). In conclusion, the presence of reciprocal ST-segment downsloping during STEMI clusters with significant perfusion and cardiac functional abnormalities, predicting the development of "no reflow" phenomenon after PCI.

Etiologies and predictors of ST-segment elevation myocardial infarction

Background and Objectives

Rapid diagnosis of ST-segment elevation myocardial infarction (STEMI) is essential for the appropriate management of patients. We investigated the prevalence, etiologies and predictors of false-positive diagnosis of STEMI and subsequent inappropriate catheterization laboratory activation in patients with presumptive diagnosis of STEMI.

Subjects and Methods

Four hundred fifty-five consecutive patients (62±13 years, 345 males) with presumptive diagnosis of STEMI between August 2008 and November 2010 were included.

Results

A false-positive diagnosis of STEMI was made in 34 patients (7.5%) with no indication of coronary artery lesion. Common causes for the false-positive diagnosis were coronary spasm in 10 patients, left ventricular hypertrophy in 5 patients, myocarditis in 4 patients, early repolarization in 3 patients, and previous myocardial infarction and stress-induced cardiomyopathy in 2 patients each. In multivariate logistic regression analysis, symptom-to-door time >12 hours {odds ratio (OR) 4.995, 95% confidence interval (CI) 1.384-18.030, p=0.014}, presenting symptom other than chest pain (OR 7.709, 95% CI 1.255-39.922, p=0.027), absence of Q wave (OR 9.082, CI 2.631-31.351, p<0.001) and absence of reciprocal changes on electrocardiography (ECG) (OR 17.987, CI 5.295-61.106, p<0.001) were independent predictors of false-positive diagnosis of STEMI.

Conclusion

In patients whom STEMI was planned for primary coronary intervention, the false-positive diagnosis of STEMI was not rare. Correct interpretation of ECGs and consideration of ST-segment elevation in conditions other than STEMI may reduce inappropriate catheterization laboratory activation.

Prognostic importance of electrocardiographic abnormalities in patients with acute noncardiac conditions

The electrocardiogram's (ECG) ability to aid in the diagnosis and risk stratification of patients with acute coronary syndromes is well established. We sought to investigate the prognostic significance of ECG abnormalities in patients with noncardiac conditions in the emergency department. Patients presenting to the emergency department who were evaluated for possible acute coronary syndrome were consecutively enrolled and an initial ECG was obtained (n = 1024). Only patients with noncardiac diagnoses were reviewed in this analysis (n=493) and 30-month follow-up was obtained. Sinus tachycardia, atrial fibrillation/flutter, ST depression, and left bundle branch block were associated with increased 30-month mortality. After controlling for history of coronary artery disease, age, sex, diabetes mellitus, hypertension, and renal insufficiency, sinus tachycardia and ST-segment depression ≥1 mm were independent predictors of 30-month mortality with a hazard ratio of 2.33 (95% confidence interval, 1.36-4.00; P = 0.002) and 2.49 (95% confidence interval, 1.10-5.67; P = 0.029), respectively. In conclusion, ST-segment depression and sinus tachycardia in patients presenting to the hospital with noncardiac conditions are independently associated with increased 30-month mortality.

Implications of ST-segment elevation in leads V5 and V6 in patients with reperfused inferior wall acute myocardial infarction

During inferior acute myocardial infarction, ST-segment elevation (ST↑) often occurs in leads V(5) to V(6), but its clinical implications remain unclear. We examined the admission electrocardiograms from 357 patients with a first inferior acute myocardial infarction who had Thrombolysis In Myocardial Infarction 3 flow of the right coronary artery or left circumflex artery within 6 hours after symptom onset. The patients were divided according to the presence (n = 76) or absence (n = 281) of ST↑ >2 mm in leads V(5) and V(6). Patients with ST↑ in leads V(5) and V(6) were subdivided into 2 groups according to the degree of ST↑ in leads III and V(6): ST↑ in lead III greater than in V(6) (n = 53) and ST↑ in lead III equal to or less than in V(6) (n = 23). The perfusion territory of the culprit artery was assessed using the angiographic distribution score, and a mega-artery was defined as a score of ≥0.7. ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than in V(6) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal to or less than in V(6) were associated with mega-artery occlusion and impaired myocardial reperfusion, as defined by myocardial blush grade 0 to 1. Right coronary artery occlusion was most common (96%) in the former, and left circumflex artery occlusion was most common (96%) in the latter, especially proximal left circumflex occlusion (74%). Multivariate analysis showed that ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than that in V(6) (odds ratio 4.81, p <0.001) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal or less than that in V(6) (odds ratio 5.96, p <0.001) were independent predictors of impaired myocardial reperfusion. In conclusion, ST↑ in leads V(5) and V(6) suggests a greater risk area and impaired myocardial reperfusion in patients with inferior acute myocardial infarction. Furthermore, comparing the degree of ST↑ in lead V(6) with that in lead III is useful for predicting the culprit artery.

Utilization of ST-segment deviation sum and change scores to identify acute myocardial infarction

OBJECTIVE

No information is currently available regarding the optimal cutoff values of the baseline ST-segment deviation sum (STDsum(baseline)) and 60-minute ST-segment deviation change (STDchange(60 min)) for predicting acute myocardial infarction (AMI).

METHODS

A retrospective study was performed in 783 admitted patients with chest pain who had suspected acute coronary syndrome and absence of left ventricular hypertrophy or bundle branch block on the initial electrocardiogram (ECG). The STDsum(baseline) was defined as the sum in millimeters (1 mm = 0.1 mV) of the absolute value of ST-segment deviations in all 12 leads at the initiation of continuous 12-lead ECG monitoring session. The STDchange(60 min) was defined as the absolute value of the difference between the baseline and 60-minute STDsum. Three cutoff values are reported and represent the smallest values in which the positive likelihood ratio (+LR) for AMI was greater than or equal to 5, 10, and 20, respectively.

RESULTS

Acute myocardial infarction occurred in 162 (20.7%) patients. The smallest cutoff value of the STDsum(baseline) for AMI with a +LR equal to or greater than 5, 10, and 20 was 9.6, 12.4, and 14.1 mm, respectively. In the subset of 699 patients without ST-segment elevation AMI on initial ECG, the smallest cutoff value of the STDchange(60 min) for AMI with a +LR equal to or greater than 5, 10, and 20 was 2.4, 3.5, and 7.9 mm, respectively.

CONCLUSIONS

Clinical studies need to be performed to determine if STDsum and STDchange, in conjunction with physician pretest probability of AMI, can be used to select patients who may benefit from emergent reperfusion therapy and other aggressive medical management strategies.

The utility of the standard 12-lead electrocardiogram in the prediction of proximal right coronary artery occlusion in acute inferior myocardial infarction

Prior studies have proposed several electrocardiogram criteria for identifying patients with acute inferior ST-segment elevation myocardial infarction (iSTEMI) caused by obstruction of the proximal part of the right coronary artery (RCA). We applied 11 of these criteria and three new ones to the admission electrocardiograms of 80 patients admitted with an acute iSTEMI in order to evaluate their utility. All patients received thrombolytic treatment and underwent coronary angiography during the hospitalization. Four previously described criteria (ST-segment depression in lead V1, ST-segment depression in leads V1-V3, maximum ST-segment depression in the precordial leads, and ST-segment depression in lead V3 of <or= 50% of the magnitude of ST-segment elevation in lead III) and two new used criteria (the absence of ST-segment depression in lead V1 in combination with ST-segment depression in lead V2 and the arithmetic sum of the ST-segment: III + V3 > 1) were useful in identifying patients with obstruction of the proximal part of the RCA. Among the six criteria, ST depression in V1-V3 had the highest specificity (77.2%) and positive predictive value (56.5%), and a new criterion-the arithmetic sum of the ST-elevation in V3/ST-elevation in III < 0.5--had the highest sensitivity (80.9%) and negative predictive value (86.7%). Six criteria were helpful in identifying patients with acute iSTEMI caused by obstruction of the proximal part of the RCA. One of these has not been previously reported and has the higher specificity and negative predictive value.

Immediate diagnosis of acute inferior wall myocardial infarction with electrocardiographic pattern of only R-wave loss in inferior leads: a case report

The 12-lead electrocardiogram is an easily obtained, non-invasive method to assist in the diagnosis of an acute myocardial infarction. Traditional electrocardiographic criteria for diagnosing inferior myocardial infarction emphasize abnormalities of the initial large Q wave or ST segment elevation in leads II, III, and aVF. We report a case that has acute R-wave loss in inferior leads as an initial manifestation of acute inferior wall myocardial infarction. The patient was stabilized by coronary angioplasty.

Clinical implications of precordial ST-segment elevation in acute inferoposterior myocardial infarction caused by proximal right coronary artery occlusion

BACKGROUND

The clinical significance of inferior wall acute myocardial infarction (MI) with combined ST-segment elevation in both anterior and inferior leads, compared with inferior leads alone, is unknown.

HYPOTHESIS

Despite having more leads with precordial ST-segment elevation, these patients may have a better outcome due to less posterior involvement, which tends to drag down the precordial ST-segment.

METHODS

A total of 158 postinferior MI patients with documented proximal right coronary artery occlusion were retrospectively studied. They were divided into three subgroups according to the magnitude of concurrent ST-segment deviation in lead V2: Group A (n = 19) had ST-segment elevation >/= 2.0 mm; Group B (n = 74) had ST-segment lay between + 2.0 mm and - 2.0 mm; and Group C (n = 65) had ST-segment depression >/= 2.0 mm. The clinical and electrocardiographic characteristics were then compared among these threes subgroups.

RESULTS

The baseline demography, prevalence of risk factors, and treatment received were of no difference among the subgroups. However, Group A patients had significantly lower peak creatinine phosphokinase level and more preserved left ventricular function than Group B and C. Moreover, they had lower total sum of inferior ST-segment magnitude, less ST-segment depression in V4-6, and more ST-segment elevation in V(4R) than Group C. Group C patients had highest in-hospital and one-year mortality although it did not reach statistical significance.

CONCLUSIONS

Precordial ST-segment elevation in inferior wall acute MI was associated with smaller infarct size and better left ventricular function, probably secondary to occlusion of a less dominant RCA, which did not result in a significant posterior infarction.

Usefulness of ST depression with T-wave inversion in leads V(4) to V(6) for predicting one-year mortality in non-ST-elevation acute coronary syndrome (from the Electrocardiographic Analysis of the Global Use of Strategies to Open Occluded Coronary Arteries IIB Trial)

ST-segment depression (ST-D) on the admission electrocardiogram of patients with non-ST-elevation acute coronary syndromes (NSTEACSs) is associated with higher mortality. However, few studies have evaluated the effect of location of ST-D and T-wave polarity on long-term prognosis of patients with NSTEACS. Electrocardiographic (ECG) and clinical data from 6,770 patients with NSTEACS randomly assigned in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO) IIB trial were analyzed retrospectively. One-year mortality was correlated with location of ST-D (leads I and aVL; II, III, and aVF; V1 to V3; or V4 to V6) and T-wave polarity. ST-D in any of the ECG locations was associated with higher mortality compared with patients without ST-D. Patients with ST-D and T-wave inversion in leads V4 to V6 had the highest 1-year mortality rate of all groups (16.2%), significantly higher compared with patients with ST-D without T-wave inversion in those leads (9.0%, p=0.001). Logistic regression analysis showed that age, hyperlipidemia, Killip class>I, history of myocardial infarction, history of heart failure, history of angina pectoris, systolic blood pressure, heart rate, sum of ST-D (odds ratio 1.061, 95% confidence interval 1.035 to 1.087, p<0.001), and ST-D with T-wave inversion in leads V4 to V6 (odds ratio 1.374, 95% CI 1.023 to 1.844, p=0.035) were independent predictors of 1-year mortality. Conversely, ST-D without T-wave inversion in leads V4 to V6 or other ECG presentations were not independent predictors of high 1-year mortality. In conclusion, ST-D with T-wave inversion in leads V4 to V6 on the admission electrocardiogram in patients with NSTEACS identifies those with higher 1-year mortality than for patients with any other ECG presentation.

Clinical, electrocardiographic, and biochemical data for immediate risk stratification in acute coronary syndromes

The recent evolution in therapeutic options for acute coronary syndromes (ACS) mandates early risk stratification in order to select the appropriate treatment strategy for individual patients. Simple clinical data derived from the patient's medical history and physical examination, a standard twelve-lead electrocardiogram (ECG), and determinations of biochemical markers of myocardial damage can be obtained in the emergency room and serve as a guide for deciding appropriate medical management and optimal use of available resources. Even the most important classification of the ACS is based upon a simple and dichotomous description of the ECG, where the presence of ST-segment elevation mandates an immediate attempt to restore coronary perfusion (either pharmacologically or mechanically), whereas its absence suggests pharmacological stabilization before further evaluation. Across the whole spectrum of ACS, clinical history data (such as older age, previous coronary events, and diabetes) and clinical variables (such as higher heart rate, lower blood pressure, and higher Killip class) are the most powerful prognostic determinants at multivariate analyses derived from large databases. The ECG adds significant and independent prognostic information using the analysis of qualitative (direction of ST-segment shift, associated T-wave inversion, and presence of conduction disturbances) and quantitative (number of leads involved, amount of ST- segment shifts, duration of QRS) characteristics. Biochemical markers of myocardial damage have also been identified as independent predictors of events. In addition, retrospective analyses of clinical trials have suggested that biochemical markers might serve as a guide to select pharmacological therapy. However, how to best combine electrocardiographic and biochemical data for immediate risk stratification remains to be further elucidated.

Abnormal intra-QRS potentials associated with percutaneous transluminal coronary angiography–induced transient myocardial ischemia

This article introduces a novel concept of abnormal intra-QRS potentials (AIQPs) associated with myocardial ischemia. AIQPs are microvolt-level potentials--subtle alterations in the QRS of the high-resolution electrocardiogram (ECG)--isolated from the unfiltered signal-averaged ECG (SAECG) by a method of mathematical modeling. The aims of the study were (1) to determine the characteristics of potentials in the SAECG related to ischemically altered activation during percutaneous transluminal coronary angiography (PTCA), (2) to determine their relationship with standard 12-lead ECG variables, and (3) to investigate whether AIQPs have a specific pathophysiologic basis in myocardial ischemia. Continuous high-resolution ECG data were acquired from 12 patients before, during, and after PTCA. SAECGs were computed every 60 seconds using an enhanced method of signal averaging. AIQP, ST-segment deviation, and changes in standard ECG QRS duration were measured in each 1-minute SAECG. AIQP amplitudes increased significantly during balloon inflation, compared with the preinflation state. AIQPs exhibited a greater prevalence (12 of 12 patients) than ST-segment deviation changes of more than 100 microV (7 of 12 patients), or measurable changes in standard QRS duration (4 of 12 patients). In patients with significant changes in 12-lead ECG variables during balloon inflation, AIQPs were strongly correlated with both ST-segment and QRS-duration changes. AIQP timing was correlated with the artery occluded, suggesting a specific, ischemia-influenced origin of the signal. AIQPs show promise as a time-localized, sensitive new ECG marker of ischemically altered ventricular activation.

The 12-lead electrocardiogram as a predictive tool of mortality after acute myocardial infarction: current status in an era of revascularization and reperfusion

Many recently published studies established the admission electrocardiogram as an excellent source of prognostic information in patients presenting with acute myocardial infarction. Using our search criteria, we identified a large number of articles but selected only the most relevant in each category. The best predictors of increased short-term mortality are ventricular tachycardia (odds ratio [OR] 6.1, 95% CI 4.6-8.3), ST-segment deviations (OR 5.1, 95% CI 4.6-8.3), high-degree atrioventricular block (OR 5.1, 95% CI 2.1-11.9), and long QRS duration (OR 4.2, 95% CI 1.8-10.4). For increased long-term mortality, the best predictors were ST-segment depression (OR 5.7, 95% CI 2.8-11.6), ST-segment elevation (OR 3.3, 95% CI 2.1-5.1), and left bundle-branch block (OR 2.8, 95% CI 1.8-4.3). In addition, our review discusses electrocardiographic markers of poor outcome that were not independent risk factors on multivariate analysis, conflicting findings, and knowledge gaps that can help plan future research efforts.

Acute coronary syndromes

Despite technologic advances in many diagnostic fields, the 12-lead ECG remains the basis for early identification and management of an acute coronary syndrome. This article reviews the use of the ECG in acute coronary syndromes.

ST-segment depression in lead aVR: a useful predictor of impaired myocardial reperfusion in patients with inferior acute myocardial infarction

STUDY OBJECTIVE

During inferior acute myocardial infarction (AMI), the ECG lead aVR is frequently ignored, and therefore its clinical significance remains unclear. We examined the relation between ST-segment deviation seen in lead aVR on ECGs obtained at hospital admission and myocardial reperfusion in patients who have experienced recanalized inferior AMIs.

DESIGN AND SETTING

Retrospective study.

PATIENTS

A total of 225 patients with inferior AMIs in whom Thrombolysis in Myocardial Infarction grade 3 flow was achieved within 6 h after symptom onset.

MEASUREMENTS AND RESULTS

Patients were classified as follows according to ST-segment deviation in lead aVR on an ECG obtained at hospital admission: group A, 103 patients with no ST-segment depression; group B, 80 patients with ST-segment depression of < or = 1.0 mm; and group C, 42 patients with ST-segment depression of > 1.0 mm. There were no differences in time from symptom onset to hospital admission or in the culprit lesion among the three groups. The degree of ST-segment elevation in leads II, III, aVF, V5, or V6, the degree of ST-segment depression in leads V1 to V4, and the sum of ST-segment deviation in these leads were lowest in group A and highest in group C. In groups A, B, and C, the incidence of impaired myocardial reperfusion, defined as myocardial blush grade 0/1, was 2%, 23%, and 67%, respectively (p < 0.001). The sensitivity and negative predictive values of ST-segment depression in lead aVR for impaired myocardial reperfusion were higher than those based on other ECG variables. Multivariate analysis showed that the degree of ST-segment depression in lead aVR was an independent predictor of impaired myocardial reperfusion (odds ratio 8.41; 95% confidence interval, 2.96 to 23.9; p < 0.001).

CONCLUSIONS

We conclude that the degree of ST-segment depression in lead aVR is a useful predictor of impaired myocardial reperfusion in patients who have experienced inferior AMIs.

Electrocardiographic findings in cardiogenic shock, risk prediction, and the effects of emergency revascularization: results from the SHOCK trial

OBJECTIVES

To evaluate electrocardiographic (ECG) parameters as predictors of 1-year mortality in patients developing cardiogenic shock after acute myocardial infarction (AMI), and to document associations between these ECG parameters and the survival benefit of emergency revascularization versus initial medical stabilization.

BACKGROUND

Emergency revascularization reduces the risk of mortality in patients developing cardiogenic shock after AMI. The prognostic value of ECG parameters in such patients is unclear, and it is uncertain whether emergency revascularization reduces the mortality risk denoted by ECG parameters.

METHODS

In a prospective substudy of 198 SHOCK (SHould we emergently revascularize Occluded Coronaries for cardiogenic shocK) trial patients, ECGs recorded within 12 hours of shock were interpreted by personnel blinded to the patients' treatment assignment and outcome.

RESULTS

The baseline heart rate was higher in non-survivors than in survivors (106 +/- 20 versus 95 +/- 24 beats/minute, P = .001). There was a significant association between the QRS duration and 1-year mortality in medically stabilized patients (115 +/- 28 ms in non-survivors versus 99 +/- 23 ms in survivors, P = .012), but not in emergently revascularized patients (110 +/- 31 versus 116 +/- 27 ms respectively, P = .343). The interaction between the QRS duration, mortality and treatment assignment was significant (P = .009). Among patients with inferior AMI, a greater sum of ST depression was associated with higher 1-year mortality in medically stabilized patients (P = .029), but not in emergently revascularized patients (P = .613, treatment interaction P = .025). On multivariate analysis, the independent mortality predictors were increasing age, elevated pulmonary capillary wedge pressure, heart rate, sum of ST depression in medically stabilized patients, and interaction (P = .016) between a prolonged QRS duration and treatment assignment. The adjusted hazard ratio for 1-year mortality per 20 ms increase in the QRS duration was 1.19 (95% CI 0.98-1.46) in medically stabilized patients and 0.81 (95% CI 0.63-1.03) in emergently revascularized patients.

CONCLUSION

ECG parameters identified patients with cardiogenic shock who were at high risk. Emergency revascularization eliminated the incremental mortality risk associated with cardiogenic shock in patients with a prolonged QRS duration, or inferior AMI accompanied by precordial ST depression. Prospective assessments of the magnitude of the treatment effect based on ECG parameters are required.

Electrocardiographic manifestations: acute inferior wall myocardial infarction

The 12-lead electrocardiogram (EKG) is an important tool in evaluating the patient with acute myocardial infarction (MI). Patients with acute inferior wall myocardial infarction (IWMI) represent a heterogeneous group in terms of morbidity, mortality, Emergency Department (ED) management, and site of occlusion in the culprit coronary artery. The standard 12-lead EKG, right-sided chest leads and posterior chest leads, in conjunction with clinical findings often provide the necessary information for the Emergency Physician (EP) to predict complications, morbidity and mortality. IWMI patients may have associated right ventricular infarction (RVI) or lateral and posterior wall extension. Each of these entities is associated with specific hemodynamic abnormalities and increased mortality. In addition, various atrioventricular (AV) blocks are commonly associated with IWMI. This article presents several cases of IWMI with EKGs and a discussion of EKG interpretation in the setting of IWMI.

The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis

The electrocardiogram is considered an essential part of the diagnosis and initial evaluation of patients with chest pain. This review summarises the information that can be obtained from the admission electrocardiogram in patients with ST elevation acute myocardial infarction, with emphasis on: (1) prediction of infarct size, (2) estimation of prognosis, and (3) the correlations between various electrocardiographic patterns and the localisation of the infarct and the underlying coronary anatomy.

Precordial ST-segment depression in inferior myocardial infarction is associated with slow flow in the non-culprit left anterior descending artery

BACKGROUND

Anterior precordial ST-segment depression (APSTD) is common in the setting of inferior myocardial infarction (IMI). The presence of APSTD correlates with increased risk of adverse outcomes in patients with acute IMI as well as more myocardium at risk as assessed by sestamibi, larger infarcts, lower ejection fractions, and more severe wall motion abnormalities in the infarct region. The ECG leads associated with APSTD (V1-V3) are generally thought to represent electrical activity subtended by the anterior myocardium, which is perfused by the left anterior descending artery (LAD). To determine whether APSTD is associated with abnormal blood flow in the uninvolved or non-culprit LAD, we assessed TIMI flow grades and corrected TIMI frame counts (CTFC) in both the culprit and non-culprit arteries of IMI patients.

METHODS

Data were drawn from the TIMI 10B trial of tenecteplase versus front-loaded tissue plasminogen activator in acute MI. Baseline ECGs were obtained within 12 hours of symptom onset, and angiography was performed 90 minutes following thrombolytic administration. A patient was considered to have precordial ST-segment depression if any ST-segment depression was present in any of leads V1-V3.

RESULTS

The majority of IMI's were due to right coronary artery occlusions, both in patients with APSTD (79.6%) and without APSTD (77.9%). In patients in whom the LAD was not the culprit artery but with APSTD were significantly less likely to have TIMI 3 flow at 90 minutes and more likely to have TIMI 2 flow. There was a trend toward slower CTFC in APSTD patients (27.2 +/- 13.4 vs. 22.6 +/- 8.5 frames/sec, p = 0.07).

CONCLUSIONS

Among patients with acute IMI associated with precordial ST-segment depression, flow in the non-culprit left anterior descending artery was slower than that in patients without APSTD. This finding may partially explain the occurrence of APSTD in IMI.

Moving toward a new definition of acute myocardial infarction for the 21st century: status of the ESC/ACC consensus conference. European Society of Cardiology and American College of Cardiology

The European Society of Cardiology and American College of Cardiology established their initial Joint Consensus Conference in July 1999 to develop a new definition of Acute Myocardial Infarction. This action was deemed necessary because of the development of new sensitive biochemical markers of myocardial necroses: Troponins T and I. There were 5 working groups, including one in Electrocardiography. The Conference adopted a definition that required only a history of "ischemic symptoms" and "a typical rise and fall" of at least one of the biochemical markers. The ECG Working Group strongly advised that a term distinctive from "myocardial infarction" such as "myocardial necrosette" be adopted as the diagnosis for an acute coronary event during which the peak biochemical marker level is below that which occurs when serial evolutionary ECG changes are observed. A pilot substudy from the GUSTO IIa Clinical Trial has identified the low end of the "ECG Change Range" to be: >2x the upper limit of normal for CK-MB, > 11 x for Troponin T, and >6 x for Troponin I.

Clinical significance of ST-segment elevation in lead V1 in patients with acute inferior wall Q-wave myocardial infarction

BACKGROUND

This study was designed to determine the clinical significance of ST-segment elevation in the precordial leads (leads V1 and V2) in acute Q-wave inferior wall myocardial infarction.

METHODS AND RESULTS

One hundred fifty-eight consecutive patients with acute Q-wave inferior wall myocardial infarction were classified into 3 groups on the basis of the initial ST-change in V1 (group 1 = 29 patients with ST elevation, group 2 = 97 patients with ST depression, and group 3 = 32 patients with no ST-segment change). The right coronary artery was the infarct-related artery in all the patients in group 1. Although there was no significant difference between groups 1 and 2, the number of left ventricular asynergic segments was larger and the incidence of major in-hospital arrhythmias was higher in groups 1 and 2 compared with group 3. Patients in group 1 had a significantly higher incidence of proximal lesion (86%) and right ventricular infarction (69%) than the other 2 groups did. When ST elevation in leads V1 and V2 was considered, 14 of 15 patients (93%) with ST elevation only in V1 had right ventricular infarction, whereas 6 of 14 patients (43%) with ST elevation in both V1 and V2 had right ventricular infarction (P =.011).

CONCLUSIONS

ST-segment elevation in V1 on admission in patients with acute Q-wave inferior wall myocardial infarction indicates a right coronary artery lesion associated with a larger infarct size and a higher incidence of major in-hospital arrhythmias.

Risk stratification in patients with inferior acute myocardial infarction treated by percutaneous coronary interventions: the role of admission troponin T

BACKGROUND

Cardiac troponin T (cTnT) elevations on admission indicate a high-risk subgroup of patients with ST-segment elevation acute myocardial infarction (AMI). This finding has been attributed to less effective reperfusion after thrombolytic therapy. The aim of this study was to determine the role of admission cTnT on the efficacy of percutaneous coronary interventions (PCIs) in inferior AMI.

METHODS AND RESULTS

One hundred fifty-nine consecutive patients with inferior ST-segment AMI were enrolled and followed up for a mean of 448 days. Patients were stratified by cTnT on admission. A cTnT >/=0.1 microg/L was found in 58% of patients. These patients had longer time intervals from onset of symptoms to therapy (P:<0. 001) and higher 30-day (10.8% versus 1.5%, P:=0.027) and long-term (17.2% versus 4.5%, P:=0.023) cardiac mortalities. Rates of the combined end point of death, nonfatal reinfarction, and need for repeated target vessel revascularization procedures were not different in cTnT groups (log rank, 0.69; P:=0.41). PCI was attempted in 93.3% of cTnT-positive and 98.5% cTnT-negative patients (P:=0.24) but was less frequently successful in patients with cTnT >/=0.1 microg/L (77.9% versus 96.9%, P:<0.001). Coronary stenting reduced 30-day and long-term cardiac mortality, particularly among cTnT-positive patients. In a multivariate analysis, cTnT indicated an approximately 5-fold-higher risk (adjusted OR, 4.6; 95% CI, 0.79 to 27.11; P:=0.089) and was a strong albeit not independent risk predictor.

CONCLUSIONS

In inferior AMI, a positive admission cTnT is associated with lower success rates of direct PCI and higher rates of cardiac events over the short and long term. These patients benefit from coronary stenting.

Value of the initial electrocardiogram in patients with inferior-wall acute myocardial infarction for prediction of multivessel coronary artery disease

BACKGROUND

Patients with inferior-wall acute myocardial infarction (AMI) who have ST-segment depression in the left precordial leads (LSTD+) on the initial electrocardiogram were reported to have more diffuse coronary artery disease (CAD) than had those without this finding (LSTD-). This suggests that LSTD+ patients may need extensive revascularization interventions more often than do LSTD- patients. However, this has not yet been confirmed.

OBJECTIVE

To compare the coronary angiographic findings and treatment strategies for patients with inferior-wall AMI according to the LSTD pattern.

METHODS

The clinical outcomes and the angiographic findings for 238 consecutive patients aged < or = 75 years who had been admitted to our hospital between 1 February 1995 and 1 February 1997 with inferior-wall AMI were retrospectively analyzed. The patients were divided into two groups according to the pattern of precordial ST-segment depression: LSTD+, ST-segment depression in leads V4-V6; and LSTD-, absence of this finding. All patients were treated according to current practice guidelines including with thrombolysis and revascularization interventions.

RESULTS

The final study population included 217 patients; 83 were LSTD+ and 134 were LSTD-. All underwent coronary angiography within 30 days of the infarction. Compared with LSTD- patients, LSTD+ patients tended to be older (mean age 62.7 +/- 11.7 versus 58.3 +/- 9.6 years, P = 0.004), and had higher incidences of hypertension (39.8 versus 24.6%, P = 0.019) previous myocardial infarction (45.8 versus 20.1%, P = 0.0001) and congestive heart failure (21.7 versus 3.7%, P = 0.00008). Three-vessel CAD was much more common, and single-vessel CAD much less common, in the LSTD+ than in LSTD- group (62.7 versus 13.4% and 8.4 versus 50.7%, P < 0.00001 for both). Coronary-artery-bypass surgery and multivessel percutaneous coronary interventions (PCI) were used in treating 65.1% of the LSTD+ versus only 6.0% of the LSTD- patients (P < 0.00001), whereas single-vessel PCI was used in treating 71.6% of the LSTD- patients versus only 24.1% of the LSTD+ patients (P < 0.00001). Thus, the LSTD- pattern predicted single-vessel disease and single-vessel PCI only, whereas the LSTD+ pattern was predictive of multivessel CAD and of use of coronary-artery-bypass surgery or multivessel PCI (predictive values of 94.0 and 65.1%, respectively).

CONCLUSIONS

Among patients with inferior-wall AMI, left precordial ST-segment depression predicts a very high prevalence of multivessel CAD and use of extensive revascularization interventions. The absence of this finding predicts nondiffuse CAD and lack of a need for extensive revascularization.

Prognostic significance of ST segment depression in lateral leads I, aVL, V5 and V6 on the admission electrocardiogram in patients with a first acute myocardial infarction without ST segment elevation

OBJECTIVES

We sought to investigate the short-term prognostic value of the admission electrocardiogram (ECG) in patients with a first acute myocardial infarction (MI) without ST segment elevation.

BACKGROUND

ST segment depression on hospital admission predicts a worse outcome in patients with a first acute MI, but the prognostic information provided by the location of ST segment depression remains unclear.

METHODS

In 432 patients with a first acute MI without Q waves or > or = 0.1 mV of ST segment elevation, we evaluated the ability of the initial ECG to predict in-hospital death.

RESULTS

The presence, magnitude and extent of ST segment depression were associated with an increased mortality, but the only electrocardiographic variable that was significant in predicting death after adjusting for baseline predictors was ST segment depression in two or more lateral (I, aVL, V5, or V6) leads (odds ratio 3.5, 95% confidence interval 1.2 to 10.6). Patients with lateral ST segment depression (n = 91, 21%) had higher rates of death (14.3% vs. 2.6%, p < 0.001), severe heart failure (14.3% vs. 4.1%, p < 0.001) and angina with electrocardiographic changes (20.0% vs. 11.6%, p = 0.04) than did the remaining patients, even though they had similar peak creatine kinase, MB fraction levels (129 +/- 96 vs. 122 +/- 92 IU/liter, p = NS). In contrast, ST segment depression not involving the lateral leads did not predict a poor outcome. Among patients who were catheterized, those with lateral ST segment depression had a lower left ventricular ejection fraction (57 +/- 12% vs. 66 +/- 13%, p = 0.001) and more frequent left main coronary artery or three-vessel disease than did the remaining patients (60% vs. 22%, p < 0.001).

CONCLUSIONS

In patients with a first non-ST segment elevation acute MI, ST segment depression in the lateral leads on hospital admission predicts a poor in-hospital outcome.

[Prognostic significance of advanced atrioventricular block in patients with acute myocardial infarction]

BACKGROUND

Advanced atrioventricular block (AB) during acute myocardial infarction (AMI), characterizes a high-risk subgroup of patients. Our aim was to determine the prognostic significance of AB and its possible peculiarities in relation to infarction localization and/or the thrombolytic therapy.

PATIENTS AND METHODS

The prospective study involved 1,239 patients with AMI. We studied clinical characteristics, as well as indexes of infarct size, short and long-term complications.

RESULTS

AB was present in 85 (6.8%) patients and was more often associated with: previous treatment with diuretics, diabetes, inferior localisation, higher number of ECG leads with elevated ST segment, and higher peak of CK. The AB was associated with a higher mortality: in-hospital (27% vs 10.6%; p < 0.01)) and after one-year (31.7% vs 19.4%; p < 0.05). Patients with AB had a different in-hospital mortality depending on anterior or inferior infarct localization (66% vs 18.5%; p < 0.001, respectively). In patients receiving thrombolytic treatment (n = 681), the duration of AB was shorter and in-hospital mortality was lower (13.7% vs 47%, p < 0.11) than that occurred in patients without this treatment (n = 558). AB had independent value for predicting in-hospital mortality (OR: 3.56; 95% CI: 1.84-6.90) and one-year mortality (OR: 2.77; 95% CI: 1.52-5.04).

CONCLUSIONS

AB is associated with larger infarcts and higher incidence of complications. The prognosis is especially poor when it is presented associated with anterior infarction and/or in patients without thrombolytic treatment. AB is a variable with independent prognostic value on the mortality.

Persistent ST segment depression in precordial leads V5-V6 after Q-wave anterior wall myocardial infarction is associated with restrictive physiology of the left ventricle

OBJECTIVES

To examine the relationship between the persistence of ST segment depression in leads V5-V6 after Q-wave anterior wall myocardial infarction (MI) and the filling pattern of the left ventricle (LV).

BACKGROUND

Precordial ST segment depression predominantly in leads V5-V6 is associated with increased in-hospital morbidity and mortality after acute myocardial ischemia, perhaps due to reduced diastolic distensibility of the LV.

METHODS

We prospectively studied 19 patients after Q-wave anterior wall MI (>6 months). All patients underwent 12-lead ECG recording, symptom-limited treadmill exercise testing with single photon emission computed tomography thallium-201 imaging, transthoracic Doppler echocardiography, cardiac catheterization and measurement of circulating atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels. Patients were classified based on the presence of ST segment depression in leads V5-V6: Group I = ST segment depression <0.1 mV (n = 10); Group II = ST segment depression > or =0.1 mV (n = 9).

RESULTS

Patients in Group II had greater LV end diastolic pressures (32.4 +/- 6.5 mm Hg vs. 14.8 +/- 6.1 mm Hg; p = 0.0001), higher plasma ANP (44.4 +/- 47.1 pg/ml vs. 10.7 +/- 14 pg/ml; p = 0.04) and BNP levels (89.4 +/- 62.7 pg/ml vs. 23.6 +/- 33.1 pg/ml; p = 0.01), greater left atrium area (20.6 +/- 3.1 cm2 vs. 17.8 +/- 2.4 cm2; p = 0.05), lower peak atrial (A), higher early (E) mitral inflow velocities, a higher E/A ratio and a lower deceleration time (167 +/- 44 ms vs. 220 +/- 40 ms; p = 0.05). Lung thallium uptake during exercise was more common in Group II (78% vs. 10%, p = 0.04).

CONCLUSIONS

Persistent ST segment depression in leads V5-V6 in survivors of Q-wave anterior wall MI is associated with increased LV filling pressure and a restrictive LV filling pattern.

Risk stratification after acute myocardial infarction in the reperfusion era

Historically, risk stratification for survivors of acute myocardial infarction (AMI) has centered on 3 principles: assessment of left ventricular function, detection of residual myocardial ischemia, and estimation of the risk for sudden cardiac death. Although these factors still have important prognostic implications for these patients, our ability to predict adverse cardiac events has significantly improved over the last several years. Recent studies have identified powerful predictors of adverse cardiac events available from the patient history, physical examination, initial electrocardiogram, and blood testing early in the evaluation of patients with AMI. Numerous studies performed in patients receiving early reperfusion therapy with either thrombolysis or primary angioplasty have emphasized the importance of a patent infarct related artery for long-term survival. The predictive value of a variety of noninvasive and invasive tests to predict myocardial electrical instability have been under active investigation in patients receiving early reperfusion therapy. The current understanding of the clinically important predictors of clinical outcomes in survivors of AMI is reviewed in this article.

Prognostic value of maximum ST-vector magnitude during the first 24 h of vectorcardiographic monitoring in patients with unstable angina pectoris

AIMS

To assess the prognostic importance of alternate ways of quantifying myocardial ischaemia by continuous ST analysis, the maximum ST vector magnitude and the area under the ST vector magnitude trend curve during the first 24 h of continuous ST monitoring.

METHODS AND RESULTS

During a 22-month period from 1991 to 1993, 195 patients admitted to our CCU with suspected unstable angina pectoris, were included in the study. During the first 24 h the patients were monitored for ischaemic episodes with computerized vectorcardiography, using a MIDA 1000 system. Twenty seven (14%) of the 195 patients died or had a non-fatal myocardial infarction within 1 year and the maximum ST vector magnitude among those patients was, on average, 201 microV compared with 118 microV in patients who survived 1 year free of myocardial infarction (P<0.01). The area under the ST vector magnitude trend curve was, on average, 1598 microVmin compared with 164 microVmin (P<0.01). By multivariate analysis, the maximum ST vector magnitude emerged as a superior predictor of death or myocardial infarction, compared with the area under the ST vector magnitude trend curve and the number of ST vector magnitude and ST change vector magnitude episodes. The maximum ST vector magnitude and age were independent predictors of death or non-fatal myocardial infarction within 1 year.

CONCLUSION

Maximum ST vector magnitude during the first 24 h of vectorcardiographic monitoring seems to be a strong predictor of subsequent death or non-fatal myocardial infarction.

Influence of thrombolytic therapy on inferior acute myocardial infarction with concomitant anterior ST segment depression

The purposes of this study were to analyze the prognostic significance of precordial ST segment depression and to determine whether thrombolytic therapy is effective for all patients with inferior acute myocardial infarction (AMI) or whether there is a different effectiveness for patients with concomitant anterior ST segment depression persisting for 24 hours or longer. Medical charts of 176 patients were studied. On the basis of ECG the patients were subclassified into three groups according to the presence, persistence, or absence of significant ST segment depression: Group 1: anterior ST segment depression persisting for less than 24 hours (45.4%); Group 2: anterior ST segment depression persisting for more than 24 hours (17.6%); Group 3: no anterior ST segment depression (37%). Age, Killip class, peak creatine kinase, hospital deaths, left ventricular ejection fraction, regional wall motion score, postinfarction angina, and ventricular/supraventricular arrhythmia of all patients were studied. Parameters of the three groups were compared: worse results were found in group 1 and the worst in group 2. This result is independent of thrombolytic therapy. Finally, the same parameters of thrombolyzed and nonthrombolyzed groups were compared: no statistically significant difference was observed. Among thrombolyzed patients the number of those with ST depression lasting more than 24 hours is lower than in nonthrombolyzed patients. It can be assumed that thrombolytic therapy in inferior AMI determines a shifting of patients from a worse prognosis group (ST segment depression persisting for more than 24 hours) to a better prognosis group (ST segment depression persisting for less than 24 hours).