RESUMO
BACKGROUND: Left ventricular ejection fraction (LVEF) is considered to be an index of LV function. However, LVEF in chronic mitral regurgitation (MR) is overestimated due to a "systolic unloading effect" into the left atrium and leads to underestimation of the degree of LV dysfunction preoperatively. The purpose of this study was to evaluate the exact degree of preoperative LV dysfunction by LVEF, according to the MR grade. METHODS: Transesophageal echocardiography (on transgastric short axis view) was performed to compare LVEF at the Pre- and Post-MVR periods, in 39 patients with chronic MR: group I, MR grade III (n = 16) and group II, MR grade IV (n = 23). RESULTS: LVEF at Pre- and Post-MVR were 63.8 +/- 6.1% and 54.8 +/- 6.0%, respectively, and the LVEF difference between Pre- and Post-MVR was 9.0 +/- 3.5 by number (14.1 +/- 5.3% by ratio) in group I. LVEF at Pre- and Post-MVR were 68.1 +/- 7.2% and 51.7 +/- 6.0%, respectively, and the LVEF difference between Pre- and Post-MVR was 16.4 +/- 4.2 by number (24.0 +/- 5.2% by ratio) in group II. CONCLUSIONS: For the exact evaluation of preoperative LV function in patients with chronic MR, we have to subtract 9.0 by number (14.1% by ratio) from the preoperative LVEF in MR grade III and 16.4 by number (24.0% by ratio) from the preoperative LVEF in MR grade IV.