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

Abstract

BACKGROUND: Endocardial visualization is suboptimal by fundamental imaging in at least 30% of patients. Second harmonic imaging was developed for visualization of myocardial contrast agents. We have hypothesized that endocardial visualization may improve with harmonic imaging compared with fundamental imaging. METHODS AND RESULTS: Accordingly, 40 consecutive patients with poor endocardial visualization by conventional echocardiography in at least 1 left ventricular segment (22-segment model) in the 4 standard views randomly underwent fundamental and harmonic imaging without contrast. The images were separately and randomly analyzed by 2 observers. Endocardial visualization was scored as 0, not visualized; 1, poorly visible; and 2, well visualized. Endocardial visualization indexes were also calculated. More segments were assigned a score of 0 (P <. 001) and 1 (P <.001) by fundamental compared with harmonic imaging, whereas harmonic imaging demonstrated more segments with a score of 2 (P <.001) compared with fundamental imaging. Endocardial visualization indexes were significantly better by harmonic imaging in the parasternal 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 second observer. Agreement between the 2 observers regarding improvement, deterioration, or no change in score between harmonic and fundamental imaging was 88% (kappa = 0. 76). Interobserver and intraobserver agreements for systolic wall thickening scores also significantly improved with harmonic compared with fundamental imaging (P <.001). CONCLUSION: Second harmonic imaging is superior to fundamental imaging for endocardial visualization in patients with suboptimal fundamental imaging.