Comparison of two methods for mechanical activation detection using high frame rate ultrasound imaging

Noninvasive, clinical tools for detection of regional myocardial mechanical activation of the left ventricle are needed. The feasibility of using high frame rate echocardiography for this purpose has previously been investigated, and several methods are now published in the literature. In this study, we have evaluated two different methods for mechanical activation detection for feasibility, simplicity, time consumption and accuracy against two invasive reference standards. An animal model including three anesthetized, open chest dogs with implanted combined sonomicrometry and electromyography (EMG) crystals was used. Data was acquired while the animals were being paced from specified locations of the heart. The mechanical activation patterns were investigated using isochrone maps generated from the ultrasound data and manual measurements of the delay in mechanical activation from the septum to the lateral wall. The coefficients of determination between the activation delay measured with ultrasound vs EMG and sonomicrometry were all above R
²
= 0.84, indicating a strong correlation for both methods. This study shows that there are benefits and limitations to each method.