Elevated Frame Rates During Exercise Echocardiography Improve Speckle Tracking Success Rate and Augment Deformation Values.

Abstract

Background: Although 2D speckle-tracking echocardiography (STE) is important for the clinical quantification of myocardial function it remains unknown whether increased frame rates during exercise STE augment tracking success and absolute deformation values. Method: 19 participants (15 male and 4 female; age 26.7±4.8) underwent step-wise exercise testing on a recumbent bicycle. Exercise started at 50 W, increasing by 30 W every 3 min until a target heart rate of 130-140 bpm was reached. During last 90 seconds of each exercise stage, echocardiographic sequences for offline quantification of longitudinal strain (LS), peak twist, untwisting velocity, basal rotation and apical rotation were acquired with high (HFPS), medium (MFPS), and low frame rates (LFPS). Differences in tracking success were determined using chi-square test and the impact of different frames rates on absolute deformation values were compared using mixed-model-analysis. Results: Utilization of HFPS significantly improved tracking success for parasternal short-axis images. LS acquired at HFPS was highest at baseline and across all exercise stages. Similar trends were observed for twist, peak untwisting velocity and apical rotation, while basal rotation showed no differences. Mixed model analysis revealed a significant effect of frame rate setting on LS (p<0.05) and untwisting velocity (p<0.05). Conclusion: In contrast to recommendations by leading organizations advocating for frame rates between 40 and 80 fps during resting conditions, with a proportional increase as heart rate rises, our findings suggest that consistently maintaining the frame rate at the highest feasible level is preferable for achieving optimal tracking success and accuracy in STE.