Galen S. Wagner

Myocardial infarction redefined - A consensus document of The Joint European Society of Cardiology/American College of Cardiology Committee f or the redefinition of myocardial infarction

This document was developed by a consensus conference initiated by Kristian Thygesen, MD, and Joseph S. Alpert, MD, after formal approval by Lars Rydén, MD, President of the European Society of Cardiology (ESC), and Arthur Garson, MD, President of the American College of Cardiology (ACC). All of the participants were selected for their expertise in the field they represented, with approximately one-half of the participants selected from each organization. Participants were instructed to review the scientific evidence in their area of expertise and to attend the consensus conference with prepared remarks. The first draft of the document was prepared during the consensus conference itself. Sources of funding appear in Appendix A. The recommendations made in this document represent the attitudes and opinions of the participants at the time of the conference, and these recommendations were revised subsequently. The conclusions reached will undoubtedly need to be revised as new scientific evidence becomes available. This document has been reviewed by members of the ESC Committee for Scientific and Clinical Initiatives and by members of the Board of the ESC who approved the document on April 15, 2000.*

Prognostic value of a coronary artery jeopardy score

The prognostic value of a coronary artery jeopardy score was evaluated in 462 consecutive nonsurgically treated patients with significant coronary artery disease, but without significant left main coronary stenosis. The jeopardy score is a simple method for estimating the amount of myocardium at risk on the basis of the particular location of coronary artery stenoses. In patients with a previous myocardial infarction, higher jeopardy scores were associated with a lower left ventricular ejection fraction. When the jeopardy score and the number of diseased vessels were considered individually, each descriptor effectively stratified prognosis. Five year survival was 97% in patients with a jeopardy score of 2 and 95, 85, 78, 75 and 56%, respectively, for patients with a jeopardy score of 4, 6, 8, 10 and 12. In multivariable analysis when only jeopardy score and number of diseased vessels were considered, the jeopardy score contained all of the prognostic information. Thus, the number of diseased vessels added no prognostic information to the jeopardy score. The left ventricular ejection fraction was more closely related to prognosis than was the jeopardy score. When other anatomic factors were examined, the degree of stenosis of each vessel, particularly the left anterior descending coronary artery, was found to add prognostic information to the jeopardy score. Thus, the jeopardy score is a simple method for describing the coronary anatomy. It provides more prognostic information than the number of diseased coronary arteries, but it can be improved by including the degree of stenosis of each vessel and giving additional weight to disease of the left anterior descending coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Defining Left Bundle Branch Block in the Era of Cardiac Resynchronization Therapy

Cardiac resynchronization therapy (CRT) has emerged as an attractive intervention to improve left ventricular mechanical function by changing the sequence of electrical activation. Unfortunately, many patients receiving CRT do not benefit but are subjected to device complications and costs. Thus, there is a need for better selection criteria. Current criteria for CRT eligibility include a QRS duration ≥ 120 ms. However, QRS morphology is not considered, although it can indicate the cause of delayed conduction. Recent studies have suggested that only patients with left bundle branch block (LBBB) benefit from CRT, and not patients with right bundle branch block or nonspecific intraventricular conduction delay. The authors review the pathophysiologic and clinical evidence supporting why only patients with complete LBBB benefit from CRT. Furthermore, they review how the threshold of 120 ms to define LBBB was derived subjectively at a time when criteria for LBBB and right bundle branch block were mistakenly reversed. Three key studies over the past 65 years have suggested that 1/3 of patients diagnosed with LBBB by conventional electrocardiographic criteria may not have true complete LBBB, but likely have a combination of left ventricular hypertrophy and left anterior fascicular block. On the basis of additional insights from computer simulations, the investigators propose stricter criteria for complete LBBB that include a QRS duration ≥ 140 ms for men and ≥ 130 ms for women, along with mid-QRS notching or slurring in ≥ 2 contiguous leads. Further studies are needed to reinvestigate the electrocardiographic criteria for complete LBBB and the implications of these criteria for selecting patients for CRT.

Evaluation of a QRS scoring system for estimating myocardial infarct size. I. Specificity and observer agreement.

We evaluated a simplified version of a previously developed QRS scoring system for estimating infarct size using observations of Q- and R-wave durations and R/Q and R/S amplitude ratios in the standard 12-lead ECG. Groups of subjects with a minimal likelihood of having myocardial infarcts and minimal likelihood of having common noninfarction sources of QRS modification were studied to establish the specificity of each of the 37 criteria. Only two criteria required modification to achieve 95% specificity. These 37 criteria form the basis of a 29-point QRS scoring system. A 98% specificity was achieved when a score of more than 2 points was required to identify a myocardial infarct. Fifty patients were studied to determine the intra- and interobserver agreement with this scoring system. Each criterion achieved at least 91% intra- and interobserver agreement. These impressive levels of specificity and observer agreement must be matched by high sensitivity of the scoring system and a good correlation between the point score and infarct size in patients with proven infarcts if the point score is to be useful for detecting and sizing infarcts. Sensitivity and correlation between point score and infarct size are evaluated in later studies in this series. The standard ECG is inexpensive and can be obtained repetitively and noninvasively; its QRS complex may be an important means of estimating the size, presence and location of myocardial infarcts.

Correlation of postmortem anatomic findings with electrocardiographic changes in patients with myocardial infarction: retrospective study of patients with typical anterior and posterior infarcts.

This retrospective study correlates electrocardiographic and histopathologic findings in 24 patients with single wellcircumscribed infarcts to determine 1) whether ECG terms commonly used to describe the location of myocardial infarcts are significant, and 2) whether the extent of infarct can be determined using QRS characteristics. Transverse sections of the hearts were photographed. Based on histologic sections, the infarct was outlined on the photograph and each section was planimetered via a sonic digitizer into a computer that was programmed to divide the left ventricle into 8 radial sectors and also into basal, mesial, and apical thirds. The percentage of infarct in each of these areas was then calculated.Of the 24 hearts evaluated 12 had posterior infarcts and 12 had anterior infarcts. Posterior infarcts principally involved the basal and mesial levels, whereas the anterior infarcts were more extensive in the apical and mesial thirds, with relative or total sparing of the base. Posterior infarcts were associated with Q waves in leads II, III and aVF in 11 instances. The other posterior infarct was associated with markedly diminished R waves in leads II, III and aVF in the presence of a horizontal axis. All anterior infarcts were associated with Q waves or markedly diminished R waves in the right precordial leads. Eight of the anterior infarcts exhibited circumferential apical involvement and all eight were associated with Q waves or markedly diminished R waves in the left precordial leads.This study documents the electrocardiographic identification of anterior, posterior, and apical infarcts by correlation with pathologic anatomy.

Prognostic value of ST segment depression in acute coronary syndromes: insights from PARAGON-A applied to GUSTO-IIb ☆

Objectives Our objectives were to develop a risk-stratification model addressing the importance of the magnitude and distribution of ST segment depression in predicting long-term outcomes and to validate the model in an analogous patient population. Background Although patients without ST segment elevation presenting with acute coronary syndromes represent an increasingly frequent population admitted to coronary care units, little attention has been paid to quantifying their ST segment abnormalities. Methods ST segment depression was categorized into three groups: 1) no ST segment depression; 2) 1-mm ST segment depression in two contiguous leads; and 3) ST segment depression > or =2 mm in two contiguous leads. A logistic regression model was developed using Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON-A) data to assess the prognostic value of the extent and distribution of ST segment depression in predicting one-year mortality. The model was validated using the non-ST segment elevation population in Global Use of Strategies To Open occluded arteries in acute coronary syndromes (GUSTO-IIb). Results ST segment depression was the strongest predictor of one-year mortality, accounting for 35% of the models predictive power. Patients with ST segment depression > or =2 mm were approximately 6 times (odds ratio [OR] 5.73, 95% confidence interval [CI] 2.8 to 11.6) more likely to die within one year than patients with no ST segment depression. On validation, the model showed good discriminatory power (c-index = 0.75). Patients with ST segment depression > or =2 mm in more than one region were almost 10 times more likely to die within one year than patients with no ST segment depression. Conclusions These data provide new evidence supporting the powerful prognostic value of the baseline electrocardiogram and, in particular, the magnitude and distribution of ST segment depression in predicting unfavorable events.

Evaluation of asynergy as an indicator of myocardial fibrosis.

SUMMARYThe presence and location of asynergy within the ventriculograms of 24 patients were compared with the quantity and site of fibrosis found in the left ventricle during postmortem examination. Asynergy was detected both qualitatively, by visual inspection, and quantitatively, by tracing end-systolic and end-diastolic outlines of the left ventricle with a sonic digitizer-computer system. The perimeters of fibrotic areas were traced during postmortem study with a sonic digitizer from photos of heart slices.For the RAO view, the qualitative and quantitative methods in the 24 hearts agreed on the presence or absence of asynergy in 58 of 72 (82%) of the anterior, posterior, and apical walls. In 12 of 14 (86%) walls in which the two methods disagreed, the presence or absence of quantitatively, but not qualitatively, determined asynergy correctly indicated the presence or absence of fibrosis within the wall. Of the 44 walls containing fibrosis, 35 (76%) demonstrated asynergy qualitatively while 42 (95%) exhibited asynergy quantitatively. Mean fibrosis increased with increasing severity of quantitatively determined asynergy: normal wall motion, 0.4% fibrosis; hypokinesis, 6.3%; akinesis, 14.3%; and dyskinesis, 30.1%. For the LAO view, neither qualitatively nor quantitatively determined asynergy in the lateral and septal walls was as closely related to fibrosis as In the RAO view. The ejection fraction was linearly correlated with the percent fibrosis of the entire left ventricle (r = -0.88).This study provides evidence that quantitatively determined asynergy in the RAO ventriculogram can serve as an indicator of fibrosis within the left ventricle.

Relationships among ventricular arrhythmias, coronary artery disease, and angiographic and electrocardiographic indicators of myocardial fibrosis.

SUMMARYThis study was performed to determine the relationships among angiographic, hemodynamic, clinical, and electrocardiographic data and premature ventricular contractions (PVCs). Arrhythmias were analyzed by 24 hour Holter monitor in 244 patients evaluated for chest pain by coronary angiography and left ventriculography. Using a categorical linear model, the presence of myocardial fibrosis as indicated by both abnormal left ventricular contraction (LVC) and abnormal initial QRS on electrocardiogram was found to be the only independent predictor of both frequent and complex ventricular arrhythmias (P < .0001). All other descriptors, including the number of diseased vessels (.75% obstruction), were dependent upon abnormal LVC in their association with PVCs. When the right anterior oblique view of the left ventriculogram was divided into nine segments to allow automated quantitative analysis of LVC, the prevalence of frequent PVCs was directly related to the number of abnormally contracting segments. Of patients with 0 abnormal segments, 11% had > 2 PVC/hr, in contrast to 44%, 73% and 100% of patients with 1-3, 4-6, and 7-9 abnormal wall segments, respectively (P < 0.01). A similar quantitative relationship was found between premature ventricular contractions and abnormal initial forces indicating previous myocardial infarction on the electrocardiogram.

Quantitative analysis of the admission electrocardiogram identifies patients with unstable coronary artery disease who benefit the most from early invasive treatment

OBJECTIVES The aim of the present study was to evaluate whether the effect of an early invasive treatment strategy differed between patients sub-grouped according to their severity of myocardial ischemia, as evaluated by quantitative electrocardiographic (ECG) analysis at the time of presentation. The present study is a sub-study of the previously published Fast Revascularization during InStability in Coronary artery disease trial (FRISC-II). BACKGROUND An early invasive treatment strategy has been shown to be the preferable treatment for non-ST-segment elevation acute coronary syndromes (ACS). The population of patients with unstable coronary artery disease is heterogeneous regarding both the underlying pathology and prognosis. Early risk stratification is important to select patient subgroups that will benefit the most from a given treatment. METHODS In 2,201 patients with non-ST-segment elevation ACS, the ischemic burden at hospital admission was determined by quantitative measurements of ST-T-segment deviations on the ECG. The patients were subsequently sub-grouped in tertiles based on the amount of ST-segment deviation. The primary end point for this analysis was death or myocardial infarction (MI) within one year after study inclusion. RESULTS The invasive treatment strategy produced a reduction of approximately 50% in death or MI among the patients with intermediate or major ST-segment deviation. The findings were independent of age, gender, or troponin T status. The patients with confounding factors precluding ST analysis had a poor outcome regardless of the treatment strategy. CONCLUSIONS Ischemic burden on the admission ECG identifies patients with ACS who benefit the most from an invasive treatment strategy. When the standard ECG is scrutinized with complete quantitative measurements, it provides independent information on prognosis and benefit of treatment.

Admission standard electrocardiogram for early risk stratification in patients with unstable coronary artery disease not eligible for acute revascularization therapy: A TRIM substudy☆☆☆★★★

OBJECTIVES The purpose of this study was to determine the prognostic capacity of a single electrocardiogram (ECG) obtained early after admission to the hospital in patients suspected of non-Q-wave myocardial infarction and unstable angina pectoris. METHODS Six hundred twenty-nine patients from the TRIM study were included. The patients were divided into subgroups on the basis of ST-segment changes in the inclusion ECG. Death, acute myocardial infarction, or refractory angina (despite treatment) were registered during a follow-up period of 30 days. RESULTS Patients with ST depression had a significantly higher event rate compared with patients with other ECG changes or with normal ECG results. The difference in event rates between patients with ST depression and patients without ST depression regarding the composite of death and acute myocardial infarction was highly significant (P =.0008). A significant association between the magnitude of the ST-segment depression (in millimeters) and the risk of cardiac events was also demonstrated. Multivariate analysis proved ST depression early after admission to be an independent predictor of high risk. CONCLUSION In patients with unstable coronary artery disease, ST-segment depression at admission is a strong predictor of early (30 days) cardiac events and the extent of ST depression carries important prognostic information as well.