Regional Wall Motion Index for Infarct and Noninfarct Regions after Reperfusion in Acute Myocardial Infarction: Comparison With Global Wall Motion Index

Abstract

A regional wall motion index has been derived from two-dimensional echocardiograms by use of a 16-segment model that was subdivided into anterior (nine segments) and infero-postero-lateral (seven segments) regions. This new method is compared with the use of a previously described global wall motion index for the analysis of serial echocardiograms after reperfusion in 23 patients who had acute myocardial infarction. Mean global index improved from 1.84 ± 0.46 to 1.56 ± 0.37 at 24 hours (p < 0.01) and to 1.50 ± 0.29 after 3 days to 7 days (p < 0.02), whereas mean regional index for infarct regions improved from 2.28 ± 0.73 to 1.82 ± 0.58 at 24 hours (p < 0.01) and to 1.70 ± 0.42 after 3 to 7 days (p < 0.01), with no significant change in the noninfarct index (1.34 ± 0.32 initially and 1.28 ± 0.36 after 3 to 7 days). Although both global and regional indexes effectively demonstrate early recovery of left ventricular function, (within 24 hours in many patients), the regional index for infarct regions is higher than the global index and effectively distinguishes between infarct and noninfarct segments. An overlap index in which an additional apical segment is included in the anterior region (10 segments) for anterior infarctions and in the infero-postero-lateral region (eight segments) for inferior infarctions results in a greater differentiation between infarct and noninfarct regions, with the mean initial noninfarct overlap index (1.17 ± 0.33) significantly less than the nonoverlap index. For infarct regions, however, there is no significant difference between overlap and nonoverlap indexes, and the nonoverlap method has the advantages of simplicity and wider applicability in the absence of known coronary anatomy or other clinical information. This new method of regional wall motion analysis appears to be a usefinl addition to previous methods for the assessment of left ventricular function after myocardial infarction.