Improved endocardial visualization with second harmonic imaging compared with fundamental two-dimensional echocardiographic imaging

Background Endocardial visualization is suboptimal by fundamental imaging i n of least 30% of patients. Second harmonic imaging was developed for visua lization of myocardial contrast agents. We have hypothesized that endocardi al visualization may improve with harmonic imaging compared with fundamenta l imaging. Methods and Results Accordingly, 40 consecutive patients with poor endocard ial Visualization by conventional echocardiography in at least 1 left ventr icular segment (22-segment model) in the 4 standard views randomly underwen t fundamental and harmonic imaging without contrast. The images were separa tely and randomly analyzed by 2 observers. Endocardial visualization was sc ored as 0, not visualized; i, poorly visible; and 2, well visualized. Endoc ardial visualization indexes were also calculated. More segments were assig ned a score of 0 (P < .001) and 1 (P < .001) by fundamental compared with h armonic imaging, whereas harmonic imaging demonstrated more segments with a score of 2 (P < .001) compared with fundamental imaging. Endocardial visua lization indexes were significantly better by harmonic imaging in the paras ternal long axis (P < .005), short axis (P < .001), and apical 4-(P < .0001 ) and 2-chamber views (P < .0001). Similar results were obtained by a secon d observer. Agreement between the 2 observers regarding improvement, deteri oration, or no change in score between harmonic and fundamental imaging was 88% (kappa = 0.76). Interobserver and intraobserver agreements for systoli c wall thickening scores also significantly improved with harmonic compared with fundamental imaging (P < .001). Conclusion second harmonic imaging is superior to fundamental imaging for e ndocardial visualization in patients with suboptimal fundamental imaging.