147 Evaluation of left ventricular function assessed by 2D strain in severe mitral regurgitation with normal ejection fraction

Abstract

Surgery decision in severe mitral regurgitation (MR) depends on left ventricular ejection fraction ( LVEF ). However better markers are needed to detect early LV dysfunction. We sought to determine the ability of 2D strain assessed by speckle tracking imaging (STI) to detect subclinical LV dysfunction in severe chronic MR. We studied 11 patients (8 men, 69 ± 10 years) who had severe organic MR with a LVEF ≥ 55%, and 10 healthy controls (HC). STI was performed to measure longitudinal strain (LS) in 4 and 2 chambers views, in apical long axis view, and to assess global longitudinal strain (GLS). The etiology of MR was degenerative in 10 patients and congenital in 1 patient. MR was severe in all patients (EROA = 66±23 mm 2 ). Comparing HC vs patients, left atrial area was significantly lower (16,6±2 cm 2 vs 35±10 cm 2 ; p<0,001). There was no difference in LVEF (65,6±6% vs 63,8±3,6% ; p=ns), in end-diastolic volumes (64,5±19 ml/m 2 vs 61,5±17 ml/m 2 ; p=ns), or in GLS (-20±1,1% vs -21±3,6% ; p=ns). In the patient group, we could distinguish one group with increased GLS (n=7, GLS = -23,5±1,3% ; p<0,01 vs HC), and one with a trend for a lowered GLS (n=4, GLS = -16,6 ±0,5%; p=0,125), but this was probably due to a lack of statistical power (n=4). 3 patients in the second group were in atrial fibrillation showing the impact of MR on left cavities. Inter-observer variability was good (r=0,89). LS was significantly lower in septoapical segment in HC vs patients (-21,6 ±3,5% vs -28,6±4,8% ; p<0,0001), as well as in anteroseptobasal (-16±3,4% vs -20,9±4,5% ; p<0,01) and anteroseptomedian (-18,7±2,8% vs -24,9±5,3% ; p<0,01) segments. In patients with chronic organic MR and LVEF ≥ 55%, two populations may be highlighted by 2D-strain: one with significantly increased GLS and one with a trend for a lowered GLS. More studies are required to evaluate causes and clinical consequences.