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SUMMARY 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 THE DIAGNOSIS OF MYOCARDIAL INFARCTION has been complicated by the large number of terms that are used to specify the location of infarction based on electrocardiographic (ECG) interpretation. These include anterior, septal, lateral, high lateral, inferior, posterior, diaphragmatic, apical, basal, transmural and subendocardial. The accuracy of these distinctions remains unclear despite prior studies correlating electrocardiographic and postmortem findings."'21A wide variety of interventions, both medical and surgical, that may affect the quantity of irreversibly damaged myocardium are currently being examined. Thus there is a need for noninvasively determined descriptors of the extent of infarcted myocardium. Although exacting criteria for quantifying infarct size electrocardiographically have been proposed,22 these criteria have not been validated by anatomic observation.Because of these considerations we have developed a technique to accurately localize and determine the extent of infarcts in postmortem hearts. The purpose of the present study was to employ this technique to correlate anatomic findings with the ECG under optimal diagnostic conditions by including only those hearts with single, wellcircumscribed, anterior or posterior infarcts. 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. Methods Study PopulationHearts of deceased patients who had been evaluated in either the Duke Cardiac Care Unit or Cardiac Cath...

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