Comparison of measurement of left ventricular ejection fraction by Tc-99m sestamibi first-pass angiography with electron beam computed tomography in patients with anterior wall acute myocardial infarction

The goal of this study wets to compare measurements of left ventricular (LV ) election fraction (EF) by First-pass radionuclide angiography ("first-pas s angiography") using technetium-99m (Tc-99m) sestamibi with those by contr ast-enhanced electron beam computed tomography ("electron beam tomagraphy") as a reference technique in patients with on anterior wall acute myocardia l infarction (AMI). Twenty-five patients with first Q-wave anterior wall AM I underwent paired electron beam tomographic and first-pass angiographic st udies (mean, 1 day apart). Fourteen patients had 2 sets of measurements of the LVEF obtained by both methods (separated by at least 6 weeks), for a to tal of 39 paired measurements. LVEF by electron beam tomography was calcula ted from absolute systolic and diastolic LV chamber volumes. LV volumes by electron beam tomography were 199 +/- 51 ml at end-diastole and 111 a 42 mi at end-systole. Mean LVEF was 45 +/- 11% by first-pass tomography and 46 /- 9% by electron beam tomography. The linear correlation coefficient betwe en both methods was 0.82 (p < 0.0001), with slope = 1.0, y-intercept = -1.1 , and SEE = 6.1. The mean difference between the 2 methods was -0.7 +/- 6.0 EF units (p = 0.75). The correlation between the differences and means of both methods was 0.34 (p = 0.04), indicating a trend for first-pass angiogr aphy to overestimate LVEF in the higher range. LVEFs measured by first-pass angiography in patients with abnormal LV geometry and contraction patterns caused by anterior wall AMI agree well with those measured by electron bea m tomography in the clinically relevant range. (C) 1999 by Excerpta Medica, Inc.