Comparison of native and contrast-enhanced harmonic echocardiography for visualization of left ventricular endocardial border

Our study was designed to compare the utility of fundamental and second har monic imaging (SH) for visualization of the left ventricular (LV) endocardi al border. SH is a new imaging modality using non linear acoustic response, which may provide better endocardial border delineation. Standard apical v iews were studied in 42 patients using fundamental frequency (FF), SH witho ut contrast (1.6- to 1.8-MHz and 2.1- to 2.5-MHz transmission frequencies), and SH after an intravenous injection of 2.5 g of Levovist. The quality of endocardial delineation in 16 standard segments was scored from 0 to 2. Th e endocardial visualization index was calculated as a mean of the scores. S H with and without contrast significantly improved LV endocardial border de tection (endocardial visualization index 1.25 +/- 0.53, 1.64 +/- 0.67, 1.55 +/- 0.69, and 1.73 +/- 0.28 for fundamental, lower, and higher frequency h armonic and contrast-harmonic mode, respectively, (p < 0.005). Improvement was found in all LV segments. The number of invisible segments decreased fr om 142 (FF) to 54, 112, and 61 tin lower, higher, and contrast SH mode, res pectively, p < 0.001). Endocardial delineation in the apical segments using SH was optimal after contrast injection. In the basal LV area, contrast-en hanced images were less informative because of signal attenuation. Thus, SH significantly improves visualization of the LV endocardial border. Contras t enhancement with Levovist improves imaging of the apical segments but has no additional advantage in the basal segments. SH emerges as first-line mo dality for studies of LV function. (C) 1999 by Excerpta Medica, Inc.