Consistency of left ventricular ejection fraction measurements in the early time course of STEMI

Background: Assessment of left ventricular (LV) function and volume after ST-segment elevation myocardial infarction (STEMI) is recommended to guide clinical decision within and after hospitalization. Early after STEMI, initial LV reshaping and hypokinesia may affect analysis of LV function. A comparative evaluation of left ventricular ejection fraction (LVEF) and stroke volume (SV) by different imaging modalities to assess LV function early after STEMI has not been performed so far. Methods: LV function was assessed by LVEF and SV using serial imaging within 24h and 5 days after STEMI with cineventriculography (CVG), 2-dimensional echocardiography (2DE), 2D and 3D cardiovascular magnetic resonance (2D/3D) in 82 patients. Respective parameters were compared between modalities and to 3D gold standard CMR. Results: 2D analyses of LVEF using CVG and 2DE as well as 2D CMR yielded uniform results within 24h and 5 days of STEMI. SV assessment between CVG and 2DE at day 1 after STEMI was comparable, whereas values for SV were higher using 2D CMR on all occasions (p<0.01 all). This was due to higher LVEDV measurements. LVEF by 2D versus 3D CMR was comparable, 3D CMR yielded consistently higher volumetric values. This was not influenced by infarct location or infarct size. Conclusions Early after STEMI, 2D analysis of LVEF yielded robust results across all imaging techniques implying that CVG, 2DE, and 2D CMR can be used interchangeably in this setting. SV measurements to assess cardiac function differed substantially between imaging techniques due to higher intermodality-differences of absolute volumetric measurements.