High-Frequency Echocardiography　- Transformative Clinical and Research Applications in Humans, Mice, and Zebrafish

Echocardiography is an invaluable tool for characterizing cardiac structure and function in vivo. Technological advances in high-frequency ultrasound over the past 3 decades have increased spatial and temporal resolution, and facilitated many important clinical and basic science discoveries. Successful reverse translation of established echocardiographic techniques, including M-mode, B-mode, color Doppler, pulsed-wave Doppler, tissue Doppler and, most recently, myocardial deformation imaging, from clinical cardiology into the basic science laboratory has enabled researchers to achieve a deeper understanding of myocardial phenotypes in health and disease. With high-frequency echocardiography, detailed evaluation of ventricular systolic function in a range of small animal models is now possible. Furthermore, improvements in frame rate and the advent of diastolic strain rate imaging, when coupled with the use of select pulsed-wave Doppler parameters, such as isovolumic relaxation time and E wave deceleration, have enabled nuanced interpretation of ventricular diastolic function. Comparing pulsed-wave Doppler indices of atrioventricular inflow during early and late diastole with parameters that describe the simultaneous myocardial deformation (e.g., tissue Doppler é and á, global longitudinal strain rate and global longitudinal velocity) may yield additional insights related to myocardial compliance. This review will provide a historical perspective of the development of high-frequency echocardiography and consider how ongoing innovation will help future-proof this important imaging modality for 21st century translational research.