The Intervention Centre, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Department of Informatics, University of Oslo, Oslo, Norway.
Sci Rep. 2020 Nov 18;10(1):20088. doi: 10.1038/s41598-020-76637-7.
Measurements of the left ventricular (LV) pressure trace are rarely performed despite high clinical interest. We estimated the LV pressure trace for an individual heart by scaling the isovolumic, ejection and filling phases of a normalized, averaged LV pressure trace to the time-points of opening and closing of the aortic and mitral valves detected in the individual heart. We developed a signal processing algorithm that automatically detected the time-points of these valve events from the motion signal of a miniaturized accelerometer attached to the heart surface. Furthermore, the pressure trace was used in combination with measured displacement from the accelerometer to calculate the pressure-displacement loop area. The method was tested on data from 34 animals during different interventions. The accuracy of the accelerometer-detected valve events was very good with a median difference of 2 ms compared to valve events defined from hemodynamic reference recordings acquired simultaneously with the accelerometer. The average correlation coefficient between the estimated and measured LV pressure traces was r = 0.98. Finally, the LV pressure-displacement loop areas calculated using the estimated and measured pressure traces showed very good correlation (r = 0.98). Hence, the pressure-displacement loop area can be assessed solely from accelerometer recordings with very good accuracy.
尽管临床对左心室（LV）压力曲线的测量具有高度兴趣，但实际应用中却很少进行测量。我们通过将标准化平均 LV 压力曲线的等容、射血和充盈阶段分别缩放至在个体心脏中检测到的主动脉瓣和二尖瓣的开启和关闭时间点，从而为个体心脏估计 LV 压力曲线。我们开发了一种信号处理算法，该算法可从附着在心脏表面的微型加速度计的运动信号自动检测这些阀事件的时间点。此外，还可以结合加速度计测量的位移来使用压力曲线计算压力-位移环面积。该方法在 34 个动物的不同干预过程中进行了测试。与同时使用加速度计获得的血流动力学参考记录中定义的阀事件相比，加速度计检测到的阀事件的准确性非常好，中位数差异为 2 毫秒。估计和测量的 LV 压力曲线之间的平均相关系数为 r=0.98。最后，使用估计和测量的压力曲线计算的 LV 压力-位移环面积具有非常好的相关性（r=0.98）。因此，仅使用加速度计记录即可非常准确地评估压力-位移环面积。
