The Interventional Centre, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Physiol Meas. 2009 Dec;30(12):1429-44. doi: 10.1088/0967-3334/30/12/010. Epub 2009 Nov 12.
In this study we have investigated the accuracy of an accelerometer sensor designed for the measurement of cardiac motion and automatic detection of motion abnormalities caused by myocardial ischaemia. The accelerometer, attached to the left ventricular wall, changed its orientation relative to the direction of gravity during the cardiac cycle. This caused a varying gravity component in the measured acceleration signal that introduced an error in the calculation of myocardial motion. Circumferential displacement, velocity and rotation of the left ventricular apical region were calculated from the measured acceleration signal. We developed a mathematical method to separate translational and gravitational acceleration components based on a priori assumptions of myocardial motion. The accuracy of the measured motion was investigated by comparison with known motion of a robot arm programmed to move like the heart wall. The accuracy was also investigated in an animal study. The sensor measurements were compared with simultaneously recorded motion from a robot arm attached next to the sensor on the heart and with measured motion by echocardiography and a video camera. The developed compensation method for the varying gravity component improved the accuracy of the calculated velocity and displacement traces, giving very good agreement with the reference methods.
在这项研究中，我们研究了一种旨在测量心脏运动并自动检测由心肌缺血引起的运动异常的加速度计传感器的准确性。加速度计附着在左心室壁上，在心动周期中相对于重力方向改变其方向。这导致测量的加速度信号中的重力分量发生变化，从而导致心肌运动计算中的误差。从测量的加速度信号中计算出左心室心尖区域的圆周位移、速度和旋转。我们开发了一种数学方法，根据心肌运动的先验假设，将平移和重力加速度分量分开。通过与编程为像心脏壁一样运动的机器人手臂的已知运动进行比较，研究了测量运动的准确性。还在动物研究中研究了准确性。将传感器测量值与附着在传感器旁边的机器人手臂同时记录的运动以及超声心动图和摄像机测量的运动进行了比较。针对重力分量变化的补偿方法提高了计算速度和位移轨迹的准确性，与参考方法非常吻合。
