GyroLock: Stabilizing the Heart With Control Moment Gyroscope (CMG)—From Concept to First In Vivo Assessments

We present herein an original solution to actively stabilize the epicardium in the context of beating-heart coronary artery bypass grafting. Our solution uses a control moment gyroscope to generate the compensation torque and an accelerometer for sensing. This approach makes the designed system completely independent from the stabilizing instrument, as well as independent from any external measurement. We compare two control approaches in a simulation: The first one uses a Kalman filter with a harmonic disturbance model, and the second one uses an adaptive algorithm. Results highlight the superiority of the adaptive control for our application. The first in vivo assessments are presented, showing the efficiency of the principle under real conditions. Using only accelerometric measurements, targeted cardiac motion harmonics are reduced on the order of 68%. With an optical sensor, the reduction exceeds 90%. This constitutes an improvement compared with prior solutions, despite the presence of nonnegligible uncertainties and distant sensing.